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Increase Muscle: 5 Genes and 7 Biomarkers to Track

Introduction

You train consistently. You eat enough protein. You recover as well as life allows. And still, the results feel slower than they should — or slower than what others seem to get with less effort. That gap between effort and outcome is real, and it is rarely about motivation or discipline.

Most muscle-building advice is written for a statistical average that describes no one in particular. Standard rep ranges, generic protein targets, and one-size-fits-all training splits are built around population means. They work reasonably well for many people and fall short for others. If your biology deviates from that mean in key ways — and most people's does — generic advice will always underdeliver, and you will keep wondering what you are missing.

What changes the equation is measuring rather than guessing. Two people can follow the same program and get dramatically different results because their hormonal environment, their recovery capacity, and the way their genes influence muscle fiber composition and anabolic signaling are not the same. Tracking the right biomarkers reveals where your internal chemistry is working against you. Understanding the relevant genetic variants tells you what your body's tendencies look like — so you can train with rather than against your inherited biology.

This article takes both angles. The primary section covers the seven most informative biomarkers for muscle growth — what they measure, how to test them affordably, and what to do when a number is off. A separate section covers the five genes most relevant to muscle potential, with specific plans for each variant. You will also find a consolidated reference table, a summary of the most actionable podcast content on this subject, and evidence-supported complementary approaches that most training advice overlooks entirely.

7 Biomarkers That Reveal Your Muscle-Building Environment

Building muscle is a question of biology as much as effort. Training provides the stimulus; your internal environment determines how powerfully that stimulus is amplified — or suppressed. These seven biomarkers are the most informative windows into that environment. Getting them measured is not about optimization for its own sake. It is about finding out whether the internal conditions actually match the external work.

Biomarker 1: Total and Free Testosterone

Why it matters

Testosterone is the primary anabolic hormone responsible for increasing muscle protein synthesis, activating satellite cells, and building the tissue that training breaks down. Even levels that fall inside the "normal" lab reference range can be functionally low when they sit at the bottom of that range. What matters is not just the total amount in circulation but how much of it the body can actually use. Most circulating testosterone is bound to sex hormone-binding globulin (SHBG) and albumin. Free testosterone — the unbound fraction — is what muscle cells access directly. A person can show adequate total testosterone but a functionally low free testosterone due to high SHBG, which rises with chronic stress, certain dietary patterns, and aging.

How to measure it

Blood draw, ideally fasted and between 7–10 AM when levels peak. Request total testosterone, free testosterone, and SHBG together. Cost: $40–100 out of pocket; often covered with a documented clinical reason. Optimal targets for men: total testosterone 600–900 ng/dL, free testosterone in the upper third of the reference range. Women's optimal ranges differ substantially and should be interpreted alongside symptoms.

If the score is suboptimal: the plan without supplements

Sleep is the highest-leverage free intervention available. Research published in JAMA Internal Medicine found that restricting healthy young men to five hours of sleep per night for one week reduced daytime testosterone by 10–15% (Leproult and Van Cauter, 2011). That is a significant and fully reversible change achievable without any product. Prioritizing 7–9 hours of consolidated sleep is not optional — it is the foundation of the hormonal environment.

Beyond sleep, heavy compound resistance training (squat, deadlift, press, row) produces acute testosterone spikes and, over months, supports higher baseline levels. Reducing body fat (excess adipose tissue increases aromatase activity, converting testosterone to estrogen), limiting alcohol (which directly suppresses Leydig cell function), and managing chronic psychological stress (elevated cortisol blunts testosterone production at the HPG axis) are all high-return free actions.

If the score is suboptimal: the plan with supplements or equipment

Zinc (15–25 mg/day with food) and magnesium glycinate (200–400 mg before sleep) are the two micronutrients most consistently associated with testosterone support, particularly in those who are deficient. Cycle zinc off every 10–12 weeks to prevent copper displacement. Vitamin D3 (2,000–5,000 IU daily with K2) is associated with meaningfully higher testosterone in vitamin D-deficient individuals, which includes a substantial portion of the population in northern latitudes or indoor-heavy lifestyles.

Ashwagandha (KSM-66 extract, 300–600 mg/day) has demonstrated statistically significant testosterone increases in multiple randomized controlled trials, with the most pronounced effects in men with high cortisol or suboptimal baseline testosterone. Cycle 8 weeks on, 2–4 weeks off. Side effects are minimal at standard doses; rare cases of liver enzyme elevation with prolonged use make cycling the safer approach. If levels remain suboptimal after 3–6 months of lifestyle optimization, testosterone replacement therapy under qualified medical supervision is a legitimate and data-supported next conversation for symptomatic individuals with confirmed low levels.

Biomarker 2: IGF-1 (Insulin-like Growth Factor 1)

Why it matters

IGF-1 is produced primarily by the liver in response to growth hormone signaling. It is the downstream effector responsible for much of growth hormone's anabolic action: promoting muscle protein synthesis, activating satellite cells (the stem cells of muscle tissue), and stimulating mTOR, the central molecular switch for hypertrophy. Low IGF-1 means the training signal arrives but the amplification system runs on low power. IGF-1 also declines steadily with age beginning in the mid-twenties — one of the key biological reasons muscle gains become progressively harder to sustain over time, independent of training habits.

How to measure it

Single blood draw; timing is not critical because IGF-1 is stable throughout the day, unlike pulsatile growth hormone. Cost: $50–120 out of pocket. Optimal adult range: approximately 150–300 ng/mL, with values in the upper portion associated with better lean mass preservation. Levels consistently above 350–400 ng/mL are not desirable — very high IGF-1 is associated with elevated cancer risk in observational data and should not be targeted.

If the score is suboptimal: the plan without supplements

Resistance training with moderate-to-high volume and compound loading is the most effective stimulus for IGF-1 production. Multiple-set protocols targeting major muscle groups produce stronger GH and IGF-1 responses than low-volume work at equivalent intensity. Sleep quality is again central: the majority of growth hormone — which drives liver IGF-1 production — is released during slow-wave sleep. Adequate dietary protein at or above 1.8 g/kg/day directly supports liver IGF-1 synthesis; chronic under-eating dramatically suppresses the entire GH-IGF-1 axis independent of training quality.

If the score is suboptimal: the plan with supplements or equipment

Creatine monohydrate (3–5 g/day, no loading phase required) supports the training quality that drives IGF-1 and independently activates mTOR signaling in muscle cells, making it relevant regardless of where IGF-1 sits. For persistently low IGF-1 that does not respond to lifestyle optimization, growth hormone-stimulating peptides (CJC-1295, ipamorelin) represent the most targeted pharmacological option. These require prescription and medical supervision, carry risks including water retention and insulin resistance at higher doses, and are reserved for confirmed GH deficiency or significant age-related decline — not first-line interventions.

Biomarker 3: Cortisol and the Cortisol-to-Testosterone Ratio

Why it matters

Cortisol is catabolic — it breaks down tissue, mobilizes energy, and suppresses anabolic signaling. In short acute bursts around training, it is necessary and adaptive. In chronic elevation, it dismantles the anabolic environment that training is trying to build: muscle protein breakdown accelerates and synthesis slows. The cortisol-to-testosterone ratio captures this tension more precisely than either marker alone. When cortisol is high relative to testosterone, the body is in a net catabolic state regardless of training volume. Some performance practitioners consider this ratio the single most informative hormonal indicator of whether training is building or eroding tissue at any given point.

How to measure it

Blood draw at 8 AM, fasted (cortisol follows a circadian rhythm, peaking in early morning). For a more complete picture, four-point saliva cortisol testing tracks the full diurnal curve across morning, noon, afternoon, and evening. Cost: $30–70 for blood cortisol; $80–150 for a saliva panel. The DUTCH test ($300–400) is a premium option adding urinary cortisol metabolites and a more detailed hormonal picture. Optimal fasted morning cortisol: 10–20 mcg/dL.

If the score is suboptimal: the plan without supplements

Sleep is the dominant variable — no supplement fully counteracts chronically compressed or fragmented sleep on the cortisol front. Regular deload weeks (one lower-intensity week every 4–6 weeks during hard training blocks) give the HPA axis room to reset and are dramatically underused by people who train seriously. Brief morning cold exposure (60–90 second cold shower) initially spikes cortisol but, with regular practice, trains the stress-response system toward lower baseline cortisol over time.

Reducing training volume during periods of high life stress — rather than maintaining intensity out of habit — is one of the most practically important applications of tracking this marker. More training during a high-stress period compounds the hormonal problem rather than providing relief from it.

If the score is suboptimal: the plan with supplements or equipment

Phosphatidylserine (400–600 mg/day, taken 30 minutes before training) has randomized controlled trial evidence for blunting exercise-induced cortisol, particularly relevant during high-volume training phases. Cycle 8 weeks on, 2–4 weeks off. Ashwagandha (addressed above) also shows consistent cortisol-lowering data across multiple human trials. Rhodiola rosea (400–600 mg standardized extract, taken before training) shows cortisol modulation in human studies with a good safety profile; cycle similarly. Heart rate variability wearables (Oura ring, WHOOP) provide daily readiness data that serves as a practical proxy for cortisol burden and training readiness without requiring a blood draw.

Biomarker 4: DHEA-S

Why it matters

Dehydroepiandrosterone sulfate (DHEA-S) is the most abundant circulating steroid hormone in the body and a direct precursor to both testosterone and estrogen. Produced by the adrenal glands, it peaks in the mid-twenties and declines by approximately 80% by age 75 — one of the most dramatic and consistent markers of biological aging. Low DHEA-S is associated with reduced lean mass, increased adiposity, lower bone density, and a diminished anabolic response to resistance training. It is frequently absent from standard bloodwork, which is a significant oversight given how directly it influences the hormonal substrate supporting muscle development.

How to measure it

Blood draw, stable throughout the day. Cost: $25–60. Optimal adult range for men: approximately 200–350 mcg/dL, age-adjusted; women: 100–250 mcg/dL. Many standard labs flag values as "normal" that a functional practitioner would treat as meaningfully low in a performance or body composition context — trend over time matters alongside any single snapshot.

If the score is suboptimal: the plan without supplements

Deep sleep, stress management, and limiting chronic alcohol exposure are the primary free strategies. DHEA is an adrenal output, and the adrenals are sensitive to chronic HPA axis load — which is why chronic stress and poor sleep suppress DHEA consistently. High-intensity interval training (HIIT) performed two to three times per week has been shown to stimulate adrenal function and partially support DHEA levels, particularly in older adults.

If the score is suboptimal: the plan with supplements or equipment

DHEA is available over the counter in the United States (prescription required in most of Europe). Typical starting doses: 25–50 mg/day for men, 10–25 mg/day for women, taken in the morning to align with the natural DHEA secretion rhythm. 7-Keto DHEA — a non-androgenic metabolite that does not convert to sex hormones — is the preferred alternative for women or men concerned about androgenic or estrogenic conversion effects. Both should be cycled (10–12 weeks on, 4 weeks off) and monitored with periodic bloodwork checking testosterone, estradiol, and PSA (in men) during supplementation.

Biomarker 5: Fasting Insulin and HOMA-IR

Why it matters

Insulin is anabolic when functioning correctly — it shuttles amino acids into muscle cells, activates mTOR, and suppresses muscle protein breakdown. When cells become resistant to insulin, this shuttle system fails: muscle cells respond inadequately to insulin's signals, amino acid uptake drops, and the anabolic environment degrades quietly. Mild-to-moderate insulin resistance is far more common than most people assume and can be present for years before fasting glucose crosses any diagnostic threshold. The HOMA-IR calculation — derived from fasting glucose and fasting insulin — is one of the most informative and underused early-detection tools available.

How to measure it

Fasted blood draw (12 hours). Request fasting insulin specifically — standard metabolic panels do not include it. HOMA-IR formula: (fasting glucose in mmol/L × fasting insulin in mU/L) ÷ 22.5; online calculators handle the math. Cost: $30–60 for fasting insulin; fasting glucose is included in most standard panels. Optimal HOMA-IR: below 1.5. Values above 2.0 indicate meaningful insulin resistance; above 2.5 warrants focused intervention.

If the score is suboptimal: the plan without supplements

Walking for 10–15 minutes after meals is one of the most practical and underappreciated insulin-sensitizing strategies — it produces measurable post-meal glucose reduction and requires no equipment. Resistance training itself is among the most potent insulin sensitizers available: it increases GLUT4 transporter density in muscle cell membranes, enabling glucose uptake that partially bypasses the insulin receptor. Time-restricted eating (an 8–10 hour eating window) consistently improves fasting insulin in clinical studies. Front-loading calories toward morning and midday aligns with circadian insulin sensitivity peaks documented in randomized trial data.

If the score is suboptimal: the plan with supplements or equipment

Berberine (500 mg, two to three times daily with meals) has multiple randomized trials supporting insulin sensitization at a magnitude comparable to pharmaceutical interventions in some head-to-head studies. Start at 500 mg once daily to assess GI tolerance, then increase gradually. Cycle 10–12 weeks on, 4 weeks off. Magnesium glycinate (200–400 mg/day) improves insulin sensitivity in those who are deficient. A continuous glucose monitor (CGM) worn for two to four weeks provides real-time data on how specific foods, training timing, and sleep affect glucose regulation individually — one of the most personalized and educational health experiments available for under $100.

Biomarker 6: Creatine Kinase (CK)

Why it matters

Creatine kinase is an enzyme released by damaged muscle cells. Post-training CK elevation is normal and expected — it is part of the damage-repair signal that drives adaptation. The problem arises when CK remains chronically elevated between sessions, signaling that the body is perpetually in a repair state rather than a growth state. When recovery never catches up to the training stimulus, net muscle protein balance stays flat or negative. Tracking resting CK gives an objective measure of whether training load and recovery capacity are actually aligned — something subjective perception consistently fails to detect accurately.

How to measure it

Standard blood panel. Cost: typically included in a comprehensive metabolic panel or $20–40 separately. Test at least 48–72 hours after the last intense session to obtain a true resting baseline. Normal resting range: approximately 50–200 U/L for men, 30–150 U/L for women. Post-exercise spikes to several thousand U/L can be physiologically normal after very intense sessions; it is the persistently elevated resting baseline that signals a recovery problem.

If the score is suboptimal: the plan without supplements

Increasing rest days between sessions targeting the same muscle groups, reducing training intensity during high-stress life periods, and improving sleep are the primary free levers. Low-intensity active recovery (walking, mobility work, easy swimming) on rest days improves circulatory clearance of inflammatory byproducts without adding additional muscle damage. Contrast hydrotherapy — alternating 1–2 minutes of hot and 30–60 seconds of cold water exposure for four to five cycles — reduces inflammatory markers and accelerates CK clearance in controlled studies, and costs nothing beyond a functional shower.

If the score is suboptimal: the plan with supplements or equipment

Tart cherry juice or concentrate (480 mL/day, or a concentrated capsule equivalent) has consistent RCT evidence for reducing exercise-induced muscle damage markers including CK and accelerating return to baseline strength. Best used in the three to five days around very intense training periods rather than continuously. Omega-3 fatty acids (2–4 g EPA+DHA/day) reduce systemic inflammation and lower exercise-induced CK in controlled trials. Percussion massage devices and compression garments both show measurable effects on post-exercise CK clearance in human studies and require only a one-time equipment investment.

Biomarker 7: Serum Myostatin

Why it matters

Myostatin is a protein produced by muscle cells that functions as a biological brake on muscle growth. It limits satellite cell activation, inhibits muscle protein synthesis, and prevents muscles from growing beyond a certain genetically influenced ceiling. People with naturally lower myostatin tend to gain muscle more easily and sustain higher lean mass with equivalent training. Those with chronically elevated myostatin face a ceiling on hypertrophy that training alone often cannot overcome efficiently. Serum myostatin measurement is not yet routine clinical practice, but it is increasingly available through specialized and functional medicine labs.

How to measure it

Specialized lab test, available through functional medicine practitioners and some sports medicine clinics. Cost: $80–200. Interpretation requires clinical context — relative position within reference ranges and trends over repeated measurements matter more than any single absolute value.

If the score is suboptimal: the plan without supplements

Progressive overload resistance training consistently downregulates myostatin expression in muscle tissue — one of the most robustly documented adaptations to mechanical loading in the hypertrophy literature. Eccentric-phase emphasis appears to produce the strongest myostatin suppression per session. High protein intake (above 2 g/kg/day) and a sustained positive energy balance support a favorable myostatin-to-follistatin balance. Adequate sleep enables the anabolic hormone cycling that keeps myostatin regulated over time.

If the score is suboptimal: the plan with supplements or equipment

Creatine monohydrate (3–5 g/day) has shown myostatin-lowering effects in several human studies, adding a mechanism to its well-documented performance benefits. Epicatechin — a flavonoid concentrated in dark chocolate and green tea, also available as a supplement at 50–200 mg/day — has human pilot data suggesting it inhibits myostatin and upregulates follistatin, myostatin's natural antagonist. Evidence is promising but remains limited to small trials; treat it as an emerging strategy with a favorable safety profile. Cycle 8 weeks on, 4 weeks off. Blood flow restriction (BFR) training — using specialized inflatable cuffs to restrict venous outflow during low-load resistance exercise — produces hypertrophy signals disproportionate to the mechanical load, partly through myostatin-related pathway modulation. BFR cuffs are available for $100–300 with a well-established safety record when applied correctly.

Beyond where your biomarkers sit today, understanding your genetic tendencies adds a layer of context that explains why certain numbers look the way they do — and which training choices are most likely to produce results given your inherited biology.

What Your DNA Reveals About Your Muscle Potential

Genetics does not determine outcomes in any rigid way. But it does set tendencies — some people start with a higher biological ceiling for muscle mass, respond more strongly to specific training stimuli, or face particular bottlenecks that others do not encounter. Knowing which category applies to you makes it easier to stop working against your biology and start working with it.

The genetic landscape of muscle physiology has advanced considerably over the past two decades. Researchers like Ali Torkamani at the Scripps Research Translational Institute have helped map how genomic variants affect athletic adaptation and long-term health trajectories. Practitioners like Gary Brecka in the functional performance space have highlighted how specific gene variants — including those governing methylation, nutrient processing, and muscle fiber composition — shape individual responses to training and supplementation in ways that standard protocols never account for. Both perspectives point toward the same conclusion: genetics is context, not destiny, but ignoring that context is a costly mistake.

Gene 1: ACTN3 (R577X) — Muscle Fiber Composition

What it may affect

Alpha-actinin-3 is a structural protein expressed exclusively in fast-twitch (Type II) muscle fibers — the fibers most responsible for explosive power, strength output, and the primary growth response to heavy resistance training. The R577X variant (rs1815739) determines whether this protein is produced at all. Individuals with the RR genotype produce functional alpha-actinin-3; those with the XX genotype — present in approximately 18% of the global population — produce none. Research establishing this association, including Yang et al., 2003, American Journal of Human Genetics, found that elite power athletes were significantly more likely to carry the R allele, while endurance athletes skewed toward the XX genotype.

For hypertrophy specifically, RR individuals may have a modest advantage in responding to power-focused and short-rest protocols. XX individuals show slightly better endurance fiber efficiency but reduced fast-twitch fiber capacity — which translates to a somewhat blunted response to maximal-effort, low-rep training relative to RR counterparts.

If this gene may limit progress: the plan without supplements

XX individuals benefit most from higher-volume training with controlled eccentric phases, which drives hypertrophy effectively across fiber types regardless of fast-twitch protein composition. Pairing hypertrophy blocks with sprint intervals (4–6 × 20–30 meter efforts, twice weekly) recruits and develops fast-twitch fibers specifically. Plyometric training (jump squats, broad jumps, box step-ups) performed twice weekly progressively improves fast-twitch motor unit recruitment over time, partially compensating for the absence of alpha-actinin-3.

If this gene may limit progress: the plan with supplements or equipment

Beta-alanine (3.2–6.4 g/day in split doses to reduce tingling) buffers lactic acid in fast-twitch fibers and may partially compensate for reduced fast-twitch fiber efficiency in XX individuals. Creatine monohydrate (3–5 g/day) directly supports the phosphocreatine system that fast-twitch fibers rely on for short-duration maximal efforts — particularly relevant for XX individuals. Surface EMG biofeedback equipment allows real-time visualization of target muscle activation during training and can identify and improve fast-twitch recruitment patterns in compound movements over six to eight weeks of consistent use.

Gene 2: MSTN (Myostatin Gene) — The Muscle Ceiling

What it may affect

The MSTN gene encodes myostatin — the same protein tracked as Biomarker 7 above. Genetic variants that reduce myostatin expression or function are among the most dramatic examples of gene-driven differences in muscle mass in the scientific literature. Loss-of-function variants have been documented in humans, producing individuals with extraordinary lean mass from early childhood with no identified adverse health effects. More common population-level variants influence where an individual's myostatin setpoint sits on the spectrum.

Individuals with MSTN variants associated with higher myostatin expression face a stronger biological brake on hypertrophy. This is likely one of the most underappreciated genetic explanations for why some people plateau earlier than others at identical training ages — they are not training incorrectly; they are fighting a stronger internal suppressor.

If this gene may limit progress: the plan without supplements

Since myostatin is downregulated by progressive mechanical loading, increasing training frequency and volume progressively is the primary free strategy. Three to five resistance sessions per week with consistent progressive overload, emphasizing eccentric-focused movements, produces the strongest myostatin suppression documented in human exercise studies. High protein intake (above 2 g/kg/day) supports the follistatin-to-myostatin balance over time.

If this gene may limit progress: the plan with supplements or equipment

Epicatechin (50–200 mg/day) and creatine monohydrate (3–5 g/day) are covered in detail under Biomarker 7. Blood flow restriction (BFR) training — applying specialized inflatable cuffs at 40–60% arterial occlusion pressure for legs or 40–50% for arms during low-load resistance training — produces hypertrophy signals disproportionate to the mechanical load used, partly through myostatin pathway modulation and maximized metabolic stress. Standard protocols use 30-15-15 rep schemes across three to five sets to near failure. BFR cuffs range from $100–300 and carry a well-established safety record when applied correctly.

Gene 3: IGF1 and IGF1R — Anabolic Signal Sensitivity

What it may affect

The IGF1 gene and its receptor (IGF1R) contain variants affecting both baseline IGF-1 production and how sensitively muscle cells respond to the IGF-1 signal. The 192bp repeat in the IGF1 promoter region is associated with higher baseline IGF-1 output. Individuals with variants linked to lower production or reduced receptor sensitivity may show a blunted anabolic response to identical training — not because of inadequate effort, but because the cellular machinery receiving the growth signal is less responsive. This is one genetic explanation for why two people following the same periodized program and consuming the same dietary protein can show markedly different hypertrophy outcomes over twelve weeks.

If this gene may limit progress: the plan without supplements

Training protocols that maximize the GH-IGF-1 response emphasize compound movements, moderate-to-high volume, short rest intervals (60–90 seconds), and weekly progressive load increases. Sleep quality — specifically slow-wave sleep duration — is the most accessible free lever for supporting growth hormone pulsation and downstream IGF-1 production. Cold-to-hot contrast exposure (brief cold immersion followed by sauna use) may amplify GH pulses when timed around sleep.

If this gene may limit progress: the plan with supplements or equipment

Zinc, magnesium, and vitamin D (addressed under testosterone) also support IGF-1 pathway function through overlapping mechanisms. Resistance-trained individuals with persistently low IGF-1 despite optimized sleep, training, and nutrition — who also carry confirmed unfavorable IGF1 variants — represent the most defensible case for discussing growth hormone-stimulating peptides with a sports medicine physician. This is a targeted conversation for a specific confirmed scenario, not a general recommendation.

Gene 4: ACE (I/D Polymorphism) — Power Versus Endurance Response

What it may affect

The ACE gene encodes angiotensin-converting enzyme and has a well-characterized insertion/deletion (I/D) polymorphism that influences training adaptation profiles. The DD genotype is consistently linked to greater strength and power gains from resistance training; the II genotype is associated with superior endurance adaptation; the ID genotype shows intermediate characteristics. For muscle hypertrophy, DD individuals tend to respond more robustly to power and strength-focused training stimuli. II individuals may need to pay more deliberate attention to hypertrophy-specific parameters — volume, time under tension, shorter rest — to compensate for a relative blunting of the power-adaptation response.

If this gene may limit progress: the plan without supplements

II genotype individuals benefit from undulating periodization — alternating strength-focused weeks (3–5 rep range, longer rest) with hypertrophy-focused weeks (8–12 rep range, shorter rest) rather than committing to a single mode. Incorporating explosive training modalities (trap bar jumps, medicine ball throws, sprints) alongside conventional lifting provides stimulus for the power-adaptation pathway that II individuals respond to less efficiently. The gene shapes the most effective path to hypertrophy; it does not block it.

If this gene may limit progress: the plan with supplements or equipment

Beet root juice (500 mL/day providing approximately 400 mg dietary nitrate, consumed 2–3 hours before training) normalizes some ACE-related differences in exercise capacity by improving nitric oxide availability through a pathway that bypasses ACE enzymatic activity. Multiple RCTs support improved muscular endurance and power output with this approach. Creatine monohydrate (3–5 g/day) is universally relevant but worth emphasizing particularly for II individuals who may show less spontaneous response to power-oriented training.

Gene 5: PPARGC1A (PGC-1α) — Mitochondrial Adaptation

What it may affect

PGC-1α (encoded by PPARGC1A) is the master regulator of mitochondrial biogenesis — the process by which muscle cells build new mitochondria in response to exercise. The Gly482Ser polymorphism (rs8192678) is the most studied variant; individuals carrying the Ser allele show a blunted mitochondrial adaptation response — lower mitochondrial biogenesis per unit of training stimulus than Gly/Gly carriers. This matters for hypertrophy because mitochondrial density in muscle cells directly affects recovery between training sessions, reduces oxidative stress during and after lifting, and sustains the cellular environment where protein synthesis occurs. Poor mitochondrial adaptation means slower recovery, lower sustainable training volume, and a compressed ceiling on long-term progress independent of training quality.

If this gene may limit progress: the plan without supplements

Zone 2 cardio (conversational-pace aerobic training, 30–45 minutes per session, three to four times per week) is the most potent available stimulus for PGC-1α expression and mitochondrial biogenesis, and this holds even in those with limiting variants. Incorporating it alongside resistance training builds the oxidative infrastructure that supports more training volume and faster inter-session recovery. Sauna use (15–20 minutes at 170–180°F, three to four times per week) and brief cold exposure are independent stimuli for PGC-1α activation that layer on top of training effects without additional training stress.

If this gene may limit progress: the plan with supplements or equipment

CoQ10 (100–300 mg/day of ubiquinol form) and PQQ (pyrroloquinoline quinone, 10–20 mg/day) support mitochondrial function and biogenesis, with particular relevance for individuals whose PPARGC1A variants blunt the training-induced response. NMN (nicotinamide mononucleotide, 250–500 mg/day) raises NAD+ levels and activates sirtuins that interact directly with PGC-1α signaling; human trials show improved energy metabolism with supplementation, though performance outcome evidence is still accumulating. Cycle NMN 12 weeks on, 4 weeks off; CoQ10 and PQQ can be taken continuously. Side effects for all three are minimal at recommended doses.

The Andrew Huberman Podcast Episodes That May Change How You Train

Few public resources have synthesized exercise science as accessibly or as consistently as the Huberman Lab podcast. The episodes most directly relevant to muscle growth — particularly the multi-part series with Dr. Andy Galpin, a professor of kinesiology and expert in muscle physiology — bring peer-reviewed research into directly applicable training protocols. The following ten insights draw from that body of work and represent the most practically impactful takeaways for anyone trying to build muscle more intelligently.

1. Hypertrophy Occurs Across a Much Wider Rep Range Than Most Programs Use

A key finding emphasized repeatedly by Galpin: meaningful hypertrophy can be achieved across a range from approximately 5 to 30 repetitions per set, as long as sets are taken close to muscular failure. The 6–12 rep range produces hypertrophy efficiently, but confining all training to this range leaves stimulus variety on the table. Periodizing across rep ranges provides different mechanical and metabolic stresses and prevents the adaptation plateau that single-range programs consistently produce over time.

2. Cold Water Immersion Immediately After Lifting Blunts Muscle Growth

One of the more counterintuitive findings covered in these episodes: cold plunging or ice bathing immediately after a resistance training session blunts the hypertrophic signaling that the training just initiated. Post-training inflammation is part of the anabolic signal — cooling it aggressively too soon reduces downstream protein synthesis. Cold exposure should be delayed at least four to six hours after lifting, or reserved for non-training days entirely if hypertrophy is the primary goal.

3. Non-Sleep Deep Rest Accelerates Neuromuscular Recovery Between Sessions

Huberman consistently advocates for NSDR — non-sleep deep rest, a structured body scan or yoga nidra practice — as a free recovery tool between training sessions. A 20-minute NSDR session reduces cortisol, supports dopamine restoration, and accelerates nervous system recovery. The neurological component of recovery is as important as the muscular one; training taxes the nervous system, and NSDR addresses that specifically without requiring additional sleep.

4. Physiological Sighs Between Sets Improve Set-to-Set Performance

A specific and immediately applicable protocol: a double inhale through the nose (a short sniff stacked on top of a full inhale) followed by a long, slow exhale during rest between heavy sets activates the parasympathetic nervous system rapidly, reduces heart rate, and lowers cortisol enough to meaningfully improve readiness for the next set. This takes seconds, costs nothing, and has clear mechanistic support in respiratory physiology research.

5. Morning Sunlight Exposure Has Downstream Testosterone and Growth Hormone Effects

Getting 5–10 minutes of natural light exposure within the first hour of waking — without sunglasses — entrains the circadian clock via the suprachiasmatic nucleus. This circadian signal supports nighttime growth hormone pulsation and testosterone production through neuroendocrine pathways. It is a free, low-effort daily habit with meaningful downstream effects on the anabolic hormone environment over time, and one of the most consistently cited practical protocols in Huberman's behavioral toolkit.

6. Sauna Post-Training Extends the Anabolic Hormone Window

Huberman references data showing that sauna use (15–20 minutes at 170–180°F, performed multiple times per week) can produce growth hormone spikes of two to sixteen times above baseline, with magnitude depending on heat level, duration, and frequency. Used on training days — after post-workout protein has been consumed and not interfering with sleep timing — it extends the hormonal anabolic window beyond what training alone produces.

7. Compound Movements Drive Larger Systemic Hormonal Responses Than Isolation Work

Heavy compound movements — squat, deadlift, overhead press, row, pull-up — recruit large volumes of total muscle mass and produce substantially larger acute growth hormone and testosterone responses than isolation exercises performed at equivalent effort. Galpin explains the mechanism clearly: the larger the total muscle mass recruited per movement, the more potent the systemic anabolic hormone response. This provides a mechanistic argument for anchoring every training session with compound lifts rather than building sessions primarily around isolation work.

8. The Post-Sleep Protein Window Is an Underused Opportunity

Galpin emphasizes that the post-sleep window is overlooked in most nutrition timing discussions. An overnight fast leaves the body in mild net catabolism, coinciding with the peak morning cortisol pulse. Consuming protein (30–50 g) within 60–90 minutes of waking shifts muscle protein balance toward anabolism at a time when cortisol-driven catabolism is otherwise the dominant signal. This matters most for people who train fasted or delay their first meal significantly into the morning.

9. Training Each Muscle Group More Than Once Per Week Produces Better Hypertrophy at Equal Total Volume

Evidence discussed in these episodes suggests that training each muscle group two to four times per week produces better hypertrophy than once-weekly frequency at equivalent total volume, because protein synthesis peaks for roughly 24–48 hours after a training stimulus before returning to baseline — leaving days of potential growth signal unused in once-weekly programs. The caveat: frequency benefits are only realized when recovery capacity supports them. More frequency with poor recovery produces diminishing or negative returns.

10. Progressive Overload Requires Tracking — Not Memory

One of the most practically underrated points from the entire Huberman-Galpin series: the human brain is poor at accurately tracking training load over weeks and months without external records. Both emphasize that a written or app-based training log is not optional for consistent progressive overload. Progressive overload is the most fundamental driver of hypertrophy. Without a reference point, it cannot be systematically applied — and without systematic application, adaptation plateaus.

Alongside the science of training stimulus, a handful of non-conventional modalities have accumulated meaningful human evidence for supporting the recovery environment and anabolic conditions that make training productive over time.

Complementary Approaches With Clinical Support

Several modalities outside the mainstream of resistance training and nutrition have accumulated meaningful human evidence for muscle-related outcomes — particularly in recovery, anabolic signaling, and training capacity. The three below have the clearest mechanistic rationale and the most relevant available evidence for this specific goal.

Low-Level Laser Therapy (Photobiomodulation)

Photobiomodulation (PBM) uses red and near-infrared light (typically 630–850 nm) to penetrate tissue and stimulate mitochondrial activity via cytochrome c oxidase — enhancing ATP production in muscle cells, reducing local inflammatory markers, and accelerating tissue repair following mechanical damage from training. The mechanism operates at the cellular level and overlaps directly with the mitochondrial optimization discussed under the PPARGC1A gene and the creatine kinase biomarker: better mitochondrial function means faster CK clearance and more productive recovery between sessions.

Multiple randomized controlled trials have investigated PBM for muscle recovery and performance outcomes. Research by Leal Junior and colleagues published in Photomedicine and Laser Surgery found consistent reductions in creatine kinase levels and faster return to baseline strength following high-intensity training in PBM-treated groups versus sham controls. A 2016 meta-analysis by Ferraresi and colleagues found that pre-training PBM improved peak torque and reduced post-exercise muscle damage markers across multiple independent studies.

For practical application, PBM panels (commercial devices such as those by Joovv or Mito Red Light) are applied to targeted muscle groups for 10–20 minutes. Pre-training use primes mitochondrial function; post-training use within one hour accelerates recovery — both timing approaches are supported by available evidence. Home panels cost $300–1,500; clinical sessions run $30–80 each. Ongoing use appears safe at standard parameters, with no identified adverse effects and no established cycling requirement.

Biofeedback

Neuromuscular biofeedback uses real-time feedback from surface electromyography (sEMG) to help the nervous system learn more effective motor recruitment patterns during training. For muscle building, the relevant application is improving the ability to fully and consistently activate target muscles — since motor unit recruitment quality is one of the primary limiting factors in how effectively a given exercise stimulates the intended muscle. A muscle that is nominally being trained but chronically under-recruited relative to synergists will lag regardless of program design or nutrition quality.

Human trial evidence supports sEMG biofeedback for improving specific muscle activation, particularly in rehabilitation contexts and in athletes addressing established activation deficits. A study published in the Journal of Strength and Conditioning Research demonstrated improved quadriceps activation and subsequent strength gains with guided sEMG biofeedback during resistance training compared to conventional training alone. Evidence is strongest in clinical and rehabilitation settings; for healthy trainees, sEMG is most useful for chronically under-recruited muscles such as the glutes, lower traps, serratus anterior, and rear deltoids.

Application: consumer-grade sEMG devices (ranging $200–600) can be used during warm-up sets to identify and improve muscle activation quality before working sets begin. Fifteen to twenty minutes of biofeedback-guided activation work twice weekly targeting specific lagging muscles is a practical starting point. Improvements in recruitment quality transfer to subsequent unassisted training sessions over six to eight weeks of consistent practice.

Microbiome-Directed Therapies

An emerging body of research has identified a meaningful gut-muscle axis: specific bacterial strains affect muscle mass, systemic inflammation, protein utilization, and short-chain fatty acid production in ways with direct relevance for muscle building. Butyrate-producing bacteria reduce intestinal permeability and improve colonocyte health, supporting the absorption of the amino acids that drive muscle protein synthesis. Lactobacillus plantarum has shown muscle-relevant effects in human trials; one randomized trial found improved muscle mass and grip strength in older adults supplementing with this strain compared to placebo over twelve weeks.

A 2021 systematic review published in Nutrients found that probiotic supplementation was associated with modest but statistically significant improvements in muscle mass in human clinical trials, particularly in older adults and athletes under high training loads. Effect sizes are small compared to training and nutrition — this is an adjunct, not a primary intervention — but the absence of meaningful side effects and the low cost make it a reasonable addition once primary variables are addressed.

Practical application: a diet high in fermented foods (kefir, kimchi, sauerkraut, plain yogurt) provides diverse live bacterial exposure and prebiotic substrate at no additional cost. For a more targeted approach, a multi-strain probiotic containing Lactobacillus plantarum and Bifidobacterium strains (10–50 billion CFU/day) taken consistently for 8–12 weeks has the strongest current evidence for muscle-relevant outcomes. Pairing with prebiotic fiber (15–25 g/day from whole food sources or partially hydrolyzed guar gum) feeds the beneficial strains. Side effects are typically limited to transient GI adjustment in the first one to two weeks. Cost: quality multi-strain probiotics run $20–60 per month.

Conclusion

Building muscle efficiently is a matter of aligning your inputs with your actual biology rather than with a generic template. Generic programs can take someone a long way — but they cannot substitute for knowing where your specific hormonal environment, recovery capacity, and genetic tendencies actually sit. That knowledge is now accessible and increasingly affordable.

The most practical next step is not to implement everything at once. Start with the biomarkers most likely to be informative for your situation: total and free testosterone, fasting insulin, and IGF-1 form a strong three-panel starting point obtainable from most labs for under $200. If you have access to genetic testing (services such as 23andMe provide raw data analyzable through third-party interpretation tools), ACTN3 and MSTN are the variants most likely to reveal something immediately useful about your training response. From there, work through the specific protocols matched to your results — free interventions first, targeted supplementation only where your data and the evidence align clearly.

Discuss significant hormonal findings with a qualified sports medicine physician, endocrinologist, or functional medicine practitioner before adding pharmacological interventions. The information above is a starting map — using it well means knowing where you actually are before deciding where to go next.