GABA Supplements — Body Handbook

Supplements · §506

GABA Supplements

The bottle on the supplement-store shelf promises calm, faster sleep, lower blood pressure, a growth-hormone boost. The molecule inside is real — GABA is the main calming chemical your brain runs on. The catch is whether swallowing it does anything to the brain, and after forty years of arguing about it, the honest answer is: probably not much, mostly not the way the label implies. There are small real effects, mostly on systems outside your skull. Knowing the actual size of what you're paying for is the whole entry.

Know · As-needed Evidence Mixed Chapter Supplements

The effect a careful reader can expect is modest: a small calming nudge in the hour after a pill, a few minutes off sleep onset some nights, a real but limited blood-pressure dip if yours already runs a bit high. None of it is medication-grade, and the headline mechanism — calming your brain directly — is still unproven in humans. Cheap, safe at sensible doses, and easily beaten by light hygiene, late-caffeine cuts, and the proven sleep and stress tools. Worth understanding so the supplement aisle stops selling you on the wrong story.

GABA — short for gamma-aminobutyric acid — is the brake pedal of your brain. When a neuron releases it, the next neuron quiets down. That's how anxiety medications like Valium and Xanax work: they hold the brake harder. So the supplement pitch writes itself: take GABA, brake the brain, get calmer.

The problem is the brain has a gatekeeper. The blood–brain barrier — a tight layer of cells around your brain's blood vessels — lets some molecules through and blocks most. GABA, structurally, is one of the ones it's designed to keep out: small but electrically charged, exactly the wrong profile for slipping through a wall of fatty membranes. Whether any GABA from a capsule actually reaches your brain in amounts that would matter has been argued in the literature for four decades, and the most cited independent review of the question concludes the evidence is contradictory and inconclusive — but mostly leans toward no Boonstra et al. 2015.

What can happen instead is peripheral. The molecule lands in your gut, where it can act on the nerves of the digestive tract, on the vagus nerve, on the pancreas, and on small blood vessels — none of which require crossing the brain's barrier. Your brain may then feel something downstream, the way it feels a warm drink or a deep breath — through the body, not through the molecule arriving at neurons. This peripheral story is the leading hypothesis for whatever real effects the supplement does have Boonstra et al. 2015.

What the trials actually show

The honest summary, written by a team of academics with no skin in the game: limited evidence for stress reduction, very limited evidence for sleep. That's the verdict of the 2020 systematic review of every published human trial of oral GABA, by Hepsomali and colleagues at Roehampton and Swinburne Hepsomali et al. 2020. "Limited" doesn't mean zero — it means the trials are mostly small, mostly single-site, often single-blind, and frequently run by people whose paycheque comes from selling the product.

For sleep, the best polysomnography trial — actually wiring people up and measuring brain activity overnight — gave 40 insomnia patients 300 mg of GABA from a fermented rice-germ extract for four weeks. Time-to-sleep dropped versus placebo; sleep efficiency improved Byun et al. 2018. That's the one rigorous human sleep trial in the literature, and it used a fermented-food product rather than plain GABA in a capsule, so the active ingredient could be the matrix as much as the molecule.

The blood-pressure trials are the most interesting, because the effect size is actually meaningful and the design is harder to dismiss. A daily glass of fermented milk delivering just 10 mg of GABA, over twelve weeks, dropped systolic blood pressure by roughly 14 mmHg in mildly hypertensive Japanese adults — and the drop stayed for the duration of the trial Inoue et al. 2003. A double-blind follow-up using GABA-rich Chlorella showed a smaller but real systolic reduction in people with borderline hypertension Shimada et al. 2009. The catch: normotensive people in the same trials didn't move. The effect only shows up if your starting pressure is already elevated.

The growth-hormone story is the loudest claim in the bodybuilding corner and it is, mechanically, real. Eleven young weight-trained men took 3 grams of GABA at rest; their peak growth-hormone reading shot up around 400% over the placebo session Powers et al. 2008. The trick is that a single hour-long hormone spike is not the same as building muscle. A 12-week training trial that paired 100 mg of GABA with whey protein did show a small additional gain in lean mass over whey alone — about an extra pound — but only because the men were also lifting weights and eating protein Sakashita et al. 2019. There is no evidence that GABA on its own, without training, changes your body composition.

What you're actually buying

The reader spending $20–30 a month on GABA capsules for sleep is, in most cases, paying for placebo plus a small peripheral nudge. That's not nothing — placebo is real and a small nudge is a small nudge. But it's also not what the bottle implies. The version of the reader who keeps buying it for years pays a few hundred dollars and never gets around to the larger interventions sitting next to it: a dark bedroom, a fixed wake time, no caffeine after lunch, a sleep study if snoring is in the picture. Each of those is free or one-time, and each does more.

For someone whose blood pressure runs high and who is hoping a supplement can replace a clinic visit, the stakes are sharper. A 14 mmHg drop sounds large, but the trial that produced it used a food product and twelve weeks of compliance, and the average GABA capsule on the shelf has not been tested for the same effect. Substituting any supplement for an actual workup — and, if needed, an actual medication — is the route people regret later. The conversation with a clinician is the move; this entry is not it.

If you're going to try it anyway

For sleep onset, the dose used in the closest thing to a real trial is 100–300 mg, taken 30 to 60 minutes before bed Byun et al. 2018. For stress in the moment, the EEG and arithmetic-task trials used 100 mg roughly an hour before the stressor Abdou et al. 2006 Yoto et al. 2012. Higher doses don't reliably help more; they just cost more.

The growth-hormone use case is a separate calculation. A 3-gram dose around training produces an acute hormone spike, but the only body-composition signal in the literature required twelve weeks of consistent lifting and whey protein alongside it Powers et al. 2008 Sakashita et al. 2019. If you are not already training and eating enough protein, the supplement is not the missing piece.

The U.S. Pharmacopeia's 2021 safety review pulled together every published human exposure it could find — doses up to 18 g a day for a few days, and 120 mg a day for 12 weeks — and found no serious adverse events attributable to GABA itself USP 2021. At the high end of acute dosing (over five grams in one go) people report a burning sensation in the throat, mild shortness of breath, tingling, flushing, drowsiness, or stomach upset; these pass.

Pregnancy and breastfeeding have no human safety data — skip it. If you're on a blood-pressure medication, the small additional drop GABA might add isn't a clinical-magnitude risk, but it's a good reason to mention it to your prescriber so they can watch the numbers.

What the marketing gets wrong

"It works like a benzodiazepine, just gentler." No. Benzodiazepines work because they're fat-soluble molecules designed to slip across the blood–brain barrier and grab onto your brain's GABA receptors directly. Oral GABA doesn't do that — the molecule's shape is wrong for the barrier. Whatever calming effect you get is doing something different, probably via your gut and vagus nerve, on a different timescale and at a much smaller magnitude Boonstra et al. 2015.

"PharmaGABA is naturally produced, so it's different." The molecule produced by Lactobacillus hilgardii fermentation is the same molecule as synthetic GABA. Different starting material, identical product. Trials sponsored by the company that owns the brand tend to find advantages; independent head-to-heads do not exist. You're paying for the marketing, not a different active ingredient.

"The 400% growth-hormone spike means it builds muscle." The spike is real but acute — it lasts an hour Powers et al. 2008. Your body releases far larger growth-hormone pulses every night during deep sleep without any supplement. The one trial that showed a body-composition effect needed concurrent resistance training and protein Sakashita et al. 2019; the GABA was an additive on top of work you were already doing.

"The big blood-pressure trials prove it works for everyone." The trials were in people whose pressure was already elevated, and the GABA was delivered in fermented milk or chlorella, not capsules Inoue et al. 2003 Shimada et al. 2009. Normotensive people in the same trials did not move. The product, the population, and the matrix all matter.

What has more evidence

If the reason you're holding the bottle is sleep: a dark, cool bedroom and a fixed wake time outperform any supplement in this category, and they're free. L-theanine and glycine have larger and cleaner evidence bases than GABA for sleep onset. If snoring is in the picture, screening for sleep apnea matters more than any over-the-counter aid.

If the reason is anxiety in the moment: a few minutes of slow nasal breathing reliably moves heart rate and stress markers in seconds, not an hour. L-theanine has more replicated relaxation data and is often cheaper.

If the reason is blood pressure: the actual effect sizes — sodium reduction, weight loss, regular exercise, and, when warranted, a half-tablet of a first-line antihypertensive — are an order of magnitude larger than the GABA signal, even taking the food-matrix trials at face value.

If the reason is more growth hormone: sleep is the largest natural GH driver in the day. High-intensity exercise is the second. A supplement is a distant third.

What changes when you stop, or never start

For the reader currently spending on GABA capsules, stopping doesn't feel like much. The lights stay on. Sleep is roughly the same — possibly a touch worse for a few nights if you were getting a placebo bump, then back to baseline. Calm in the moment is unchanged. The most honest payoff is what happens with the freed attention: you notice when you actually got tired, what you ate, what time you stopped looking at your phone. The thing you were medicating with the capsule starts to have a name. Most often that name is "I'm under-slept" or "I drink coffee too late" or "I haven't taken a walk outside today."

The thirty dollars a month adds up. Over a year, it's the cost of a sleep-tracker, a single visit to a sleep clinic, or three months of L-theanine. Over five years, it's a noticeable line in a budget that was being quietly debited for a small effect. The reader who stops and reroutes — to the dark bedroom, the fixed wake time, the walk before lunch — is the reader the catalogue is for.

Adjacent topics worth a look: L-theanine and glycine for sleep and acute calm, both with deeper evidence bases than GABA itself. Magnesium glycinate for sleep and muscle relaxation. Light hygiene — morning sun, dark bedroom, no bright screens late — the largest free lever on sleep. Caffeine timing, which often explains the sleep problem GABA was being asked to solve. Sleep apnea screening if snoring or daytime fatigue is in the picture. Slow nasal breathing for stress in the moment, faster and free. Prescription anxiolytics and sleep aids are a separate decision with a clinician — not a supplement question.

Substance and claimed effects

Oral gamma-aminobutyric acid (GABA) supplements deliver the brain's main inhibitory neurotransmitter as a pill, powder, or fermented-food extract. Common forms include synthetic GABA, PharmaGABA (produced by Lactobacillus hilgardii fermentation), GABA-rich fermented milk, GABA-rich Chlorella, and fermented rice-germ extract. Typical doses range from 100–200 mg daily, although trials span 10 mg to 800 mg. The marketing claims cluster around four consequences: relaxation and anxiety reduction, faster sleep onset and better sleep quality, modest blood-pressure lowering in mildly hypertensive adults, and acute elevation of growth hormone (GH). The mechanism question dominates the field — endogenous GABA is the principal CNS inhibitory transmitter, but whether orally ingested GABA reaches the brain in pharmacologically relevant amounts has been debated for forty years Boonstra et al. 2015.

Evidence by addressing question

Mechanism

Science. GABA is a small, highly polar, zwitterionic amino acid. Its physicochemical profile (low lipid solubility, charge at physiological pH) predicts very poor passive diffusion across the blood–brain barrier (BBB). Early rodent isotope-tracer work (Knudsen, van Gelder, and others, 1980s–1990s, summarised in Boonstra et al. 2015) gave inconsistent estimates of BBB permeability — some studies showed essentially zero penetration, others detected trace amounts via the LAT1/CAT-class amino-acid carriers. Critically, no high-capacity influx system for GABA into healthy adult human brain has been demonstrated, and human MR-spectroscopy data quantifying cortical GABA after oral dosing are absent.

Mechanism (peripheral routes). Because the central-action story is weak, attention has shifted to peripheral mechanisms. GABA receptors are expressed on enteric neurons in the submucosal and myenteric plexuses, on vagal afferents, on pancreatic islet cells, and on cardiovascular smooth muscle. Oral GABA can plausibly act on the enteric nervous system, modulate vagal afferent firing (and through it hypothalamic–limbic state), and produce systemic effects (blood pressure, GH release via hypothalamic GHRH disinhibition) without ever entering the CNS through the BBB Boonstra et al. 2015. The growth-hormone elevation is consistent with a hypothalamic-pituitary axis effect — GABA-A agonism in the hypothalamus inhibits somatostatin and disinhibits GHRH, even when central GABA does not change appreciably — though the exact route remains a hypothesis.

Evidence

Stress and relaxation. The frequently cited human EEG study had thirteen subjects ingest 100 mg GABA, water, or L-theanine in a within-subjects design; 60 minutes post-ingestion, GABA increased EEG alpha-wave power and decreased beta-wave power, interpreted as relaxation Abdou et al. 2006. The same paper reported preservation of salivary IgA in eight acrophobic subjects crossing a suspended bridge after GABA. Both arms are small, single-site, single-blind, and the senior author was affiliated with a GABA manufacturer — a conflict the systematic-review literature flags Boonstra et al. 2015 Hepsomali et al. 2020. A follow-up arithmetic-task study (n=30) reported smaller chromogranin-A rises and lower task-induced alpha-wave decrement with 100 mg GABA versus placebo Yoto et al. 2012. The 2020 systematic review of human trials concluded that across the published literature there is limited evidence for stress reduction and very limited evidence for sleep from oral GABA Hepsomali et al. 2020.

Sleep. Randomised data on isolated GABA for sleep are thin. A 4-week double-blind trial of fermented rice-germ extract delivering 300 mg GABA in 40 insomnia patients reported reduced sleep-onset latency and improved sleep efficiency by polysomnography versus placebo Byun et al. 2018. A rodent EEG study showed that a GABA + L-theanine mixture cut sleep latency ~21% and increased NREM sleep ~21% versus either ingredient alone Kim et al. 2019; there are no published human polysomnography trials of the same combination. PharmaGABA-branded trials report subjective sleep-quality improvements but typically lack rigorous controls.

Blood pressure. The cleanest signal in the literature. A 12-week single-blind trial of fermented milk delivering 10 mg/day GABA in 39 mild hypertensives produced a sustained systolic drop of roughly 17 mmHg versus placebo Inoue et al. 2003. A 12-week double-blind RCT of GABA-rich Chlorella delivering 40 mg/day GABA in 80 subjects with high-normal blood pressure or borderline hypertension produced a smaller but significant systolic reduction versus placebo, larger in the borderline-hypertensive subgroup Shimada et al. 2009. The effect appears confined to baseline-elevated BP — normotensives do not show meaningful change. Mechanism likely peripheral (sympathetic dampening via enteric/vagal route, possible direct vascular effect), not central.

Growth hormone. A within-subjects crossover in 11 resistance-trained men tested 3 g GABA versus placebo at rest and after lower-body resistance exercise. Resting peak immunoreactive and immunofunctional GH rose ~400% over placebo, with the area-under-curve ~375% higher; the exercise condition added a further multiplicative rise of GH at 30–60 minutes post-ingestion Powers et al. 2008. A 12-week trial pairing 100 mg/day GABA with 10 g/day whey protein during resistance training in 21 men showed elevated resting GH at weeks 4 and 8 and significantly greater whole-body fat-free-mass gain versus whey alone Sakashita et al. 2019. The acute GH response is robust; whether translating into clinically meaningful body-composition change requires concurrent training and protein, and the effect size is modest (a few hundred grams of additional lean mass over 12 weeks).

Protocol

Practice. Marketed doses run 100–750 mg per capsule; trials supporting any clinical claim used 100–300 mg for stress/sleep, 10–40 mg for blood pressure (always in a food matrix), and 3 g acutely for growth hormone. Onset for the EEG/stress effects is reported within 30–60 minutes Abdou et al. 2006; sleep trials dose 30–60 minutes pre-bed Byun et al. 2018; blood-pressure effects required 2–4 weeks to emerge and persisted over 12 weeks Inoue et al. 2003. Tolerance and dependence have not been demonstrated at these doses.

Contraindications

Practice / safety. The 2021 USP safety review aggregated published human exposures up to 18 g/day for four days and 120 mg/day for 12 weeks; no serious adverse events were attributable to GABA across the included literature USP 2021. Reported mild effects at high acute doses (≥5 g): transient burning sensation in the throat, mild dyspnea, paresthesias, flushing, drowsiness, GI upset. Pregnancy and lactation have inadequate human safety data and are conventional exclusions. The plausible interaction concerns are pharmacodynamic, not pharmacokinetic: stacking with alcohol, benzodiazepines, Z-drugs, gabapentinoids, or other GABAergic CNS depressants could in principle compound sedation, although clinical-magnitude reports are absent; and the BP-lowering signal makes co-administration with antihypertensives a theoretical risk for hypotension USP 2021.

Misconceptions

Three persistent claims do not survive the literature. First, that oral GABA "works like a benzodiazepine on the brain" — there is no direct evidence of CNS GABA receptor agonism from oral dosing in humans Boonstra et al. 2015. Second, that PharmaGABA is meaningfully different from synthetic GABA in pharmacology — fermentation route differs, but the molecule and its physicochemical handling by the body are identical; superior trial outcomes for PharmaGABA largely reflect industry-sponsored studies. Third, that the GH spike is muscle-building on its own — Powers 2008 showed a large acute GH excursion Powers et al. 2008, but a single acute hormone peak does not equate to chronic anabolic effect, and the only RCT showing body-composition change combined GABA with whey protein and a resistance-training programme Sakashita et al. 2019.

Alternatives

For sleep-onset and anxiety, the evidence base for L-theanine, glycine, magnesium glycinate, ashwagandha, and behavioural sleep hygiene is broader and uses larger trial populations. For blood pressure, lifestyle change (sodium reduction, weight loss, exercise) and first-line antihypertensives have effect sizes one to two orders of magnitude larger than the GABA BP signal. For growth hormone, deep sleep and high-intensity exercise produce far larger physiological GH pulses than any acute supplement.

Failure modes

The dominant failure mode is taking GABA at marketed doses (often 500–750 mg) expecting an anxiolytic-medication effect, getting placebo-grade benefit, and concluding their anxiety is untreatable. The second is buying a "PharmaGABA" or "fermented" product at a 5× price premium for the same active. The third is combining GABA with prescription GABAergics or alcohol assuming additivity is safe — clinical-magnitude harm is rare but the combination is the genuine risk pocket USP 2021.

Stakes / payoff

For the typical reader spending $20–30/month on a GABA supplement for sleep, the stakes of continued use are mostly financial waste and a delayed engagement with whatever is actually disrupting sleep (light hygiene, late caffeine, airway issues, untreated anxiety). The payoff of stopping is similarly modest — money back, attention freed for higher-leverage interventions. For a mild hypertensive considering food-matrix GABA as monotherapy, the stakes are larger: trading a proven intervention for a modest one, with under-treatment risk.

Credibility range

Optimist case. Multiple human RCTs across stress, sleep, and blood pressure show consistent direction of effect favouring GABA over placebo, even when individual studies are small. The Abdou EEG signal Abdou et al. 2006, replicated in direction by Yoto's arithmetic-task work Yoto et al. 2012, suggests a real central effect within an hour of dosing — a timescale incompatible with placebo-only explanation. The blood-pressure trials, two of them double-blinded and 12 weeks long, show effect sizes of clinical interest Inoue et al. 2003 Shimada et al. 2009. The peripheral-mechanism story (enteric nervous system, vagal afferents, hypothalamic axis) is biologically coherent and does not require BBB crossing for plausibility. Safety is excellent across reviewed exposures USP 2021. The combined picture is a modest, real, low-risk intervention whose mechanism is peripheral rather than the marketing's implied central one.

Skeptic case. The most rigorous synthesis to date — a systematic review of human trials by independent academic teams — concluded that the evidence is limited for stress and very limited for sleep Hepsomali et al. 2020. The most-cited positive studies (Abdou, Yoto, PharmaGABA-branded work) are small, single-site, often single-blind, and frequently industry-linked. The BBB-crossing question is unresolved in humans and the field's standard textbook position is that oral GABA does not reach brain in pharmacologically relevant amounts Boonstra et al. 2015. The blood-pressure trials used food-matrix products (fermented milk, GABA-rich Chlorella) — the active ingredient could be the matrix, not isolated GABA. The growth-hormone spike is acute, and the only chronic body-composition signal required co-administration with protein and exercise Sakashita et al. 2019. Effect sizes for stress and sleep are within placebo range for over-the-counter anxiolytics generally. Compared to alternatives with deeper evidence bases (L-theanine, glycine, magnesium glycinate for sleep; lifestyle and first-line drugs for BP), GABA is not a top-tier choice on evidence.

Author's call. Oral GABA is a low-risk, low-to-modest-magnitude intervention whose marketing leans on a central mechanism the data do not support. The honest position: small real effects on subjective stress and sleep-onset latency that probably operate through peripheral routes (enteric, vagal); a clinically modest BP signal seen mainly in food-matrix delivery and only in baseline-elevated subjects; a real acute GH spike of unclear chronic relevance outside a training context. Evidence quality is mixed — many small, industry-linked trials and one academic systematic review concluding limited/very-limited evidence. Worth knowing about; not worth recommending as primary for any of its claimed uses; reasonable as a low-cost adjunct for someone already optimising the higher-leverage layers.

Stakeholder and incentive map

Commercial — supplement brands (PharmaGABA / Pharma Foods International, NOW Foods, Thorne, Source Naturals); fermented-food category builders (yogurt, kimchi); Japanese functional-food sector where GABA-enriched products are FOSHU-approved.
Professional — sleep medicine guidelines (AASM, NICE) do not list GABA supplements as a recommended therapy; hypertension guidelines (AHA/ACC, NICE) do not list any GABA product among lifestyle or pharmacological options.
Community — bodybuilding forums citing Powers 2008 as a "natural GH booster"; sleep-supplement YouTube; nootropic communities running GABA + L-theanine stacks.
Counter-incentive — independent academic groups (Boonstra, Hepsomali) reviewing the BBB and clinical-evidence questions; the USP review acting as a safety not efficacy authority.

Population variability

BP effect is conditional on baseline — only mild/borderline hypertensives showed meaningful change; normotensives did not Inoue et al. 2003 Shimada et al. 2009.
GH response was studied in young resistance-trained men Powers et al. 2008; whether older adults with age-related GH decline respond similarly is untested at these doses.
Anxiety-prone responders may experience larger subjective relaxation effects, consistent with stress-task design of the EEG trials Yoto et al. 2012.
People with disrupted gut barrier (severe IBD, leaky-gut conditions) might in principle absorb more GABA, but no data exist.
Pregnancy, lactation, and pediatric populations lack adequate safety data — exclude.

Knowledge gaps

The pivotal gap is direct human measurement: a magnetic-resonance-spectroscopy study quantifying cortical GABA before and after oral dosing would close the BBB question. No such study exists at adequate power. The second gap is a large, independent, industry-uncoupled RCT of pure synthetic GABA versus placebo for sleep onset using polysomnography — the Byun trial is the closest Byun et al. 2018 but used a fermented-rice-germ extract, leaving matrix effects unresolved. The third is a head-to-head against L-theanine and glycine for sleep, and against first-line antihypertensives for BP. The fourth is whether the GH effect produces sustained body-composition change at any dose without concurrent training and protein. Evidence that would shift the author's call: a positive blinded MRS BBB study, or a large independent RCT showing effect sizes ≥0.5 standardised-mean-difference on objective sleep or anxiety endpoints.

Scope and narrowing relative to the brief. The brief named relaxation, sleep onset, anxiety, blood pressure, and growth hormone, and raised the BBB question. All five consequences are covered. None were dropped. The BBB question gets the mechanism section and frames the dek and tagline.

Action call. Set to know rather than do or avoid. The honest editorial position is that this is an informational entry — most readers will arrive after seeing GABA in a supplement store and the central value is calibrating expectations. avoid overstates the harm (the molecule is safe at sensible doses and the BP signal is real); do would oversell the magnitude. know matches the relief-lever dream narrative — not being conned by the marketing is the payoff.

Cadence call. as-needed. Most use is situational (pre-bed, pre-stressor); the BP trials used daily food-matrix dosing but that is a niche use and the typical supplement-buyer is not on it.

Rating difficulties. Sleep and mood both scored 2 rather than 1 — there are small but real effects in the trials and dismissing them entirely would understate the evidence. They did not earn 3 because Hepsomali 2020's "very limited" and "limited" verdicts are independent-academic and cannot be ignored. Evidence scored 2 for the same reason. Controversy at 3 reflects active disagreement between industry-linked positive trials and the independent systematic-review verdict, plus the unresolved BBB question. Applicability at 3 captures the wide consumer audience (large minority of adults exposed to the marketing); did not go higher because the actual responder population is narrower than the buyer population.

Dream narrative call. Score computes to ≈18 (well below the 40 obligation threshold). Wrote one anyway in the relief / not-being-conned register because the honest hook here genuinely is debunking, and the tagline and dek benefit from compression of that lever. Below-40 entries can still warrant a narrative when the honest hook supports one (per dream-narrative.md §1).

Future-link candidates. Once they exist, this entry should cross-link to: L-theanine; glycine for sleep; magnesium glycinate; light hygiene / morning sun; dark bedroom; caffeine timing; sleep apnea screening; slow nasal breathing; benzodiazepines (decide); melatonin.

Separate-entry candidates. PharmaGABA specifically does not warrant its own entry — same molecule, same pharmacology; the brand-vs-generic distinction belongs in the misconceptions section here. Fermented foods as a GABA delivery vehicle (yogurt, kimchi, fermented milk) is a plausible separate entry under food but is broader than GABA and would not displace this one.

Hard decisions. Whether to give the GH claim a protocol callout. The acute hormone spike is real (Powers 2008) and the bodybuilding community will arrive looking for protocol, but the only chronic body-composition signal required co-administered training + protein (Sakashita 2019). Compromise: protocol section mentions the 3g acute dose for completeness but frames it explicitly as conditional on training + protein.

Contraindications. Pregnancy and breastfeeding included due to absent human safety data — standard convention. Did not include uncontrolled-hypertension (the directionality is favourable, not adverse) or cardiac-condition (no specific signal). Antihypertensive-medication interaction is mentioned in prose but is not in the closed contraindication vocabulary.