Top 8 Best Glycine Supplements for Sleep & Recovery (2026)
8 picks — ranked by our 50/50 methodology
- #1Best overall
BulkSupplements Glycine Powder
BulkSupplements.com · 100% plain glycine powder, 3 g per serving9.3/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.2
- Third-party testing25%9.0
- Dose accuracy (3 g)20%9.8
- Taste & mixability15%9.0
- Value (per 3 g dose)15%9.6
100% plain glycine powder, one scoop is the studied 3 g dose, per-batch tested, and the lowest cost per gram in the category. The default if you're fine mixing a powder.
- Form
- Plain glycine powder (unflavored)
- Per serving
- 3 g — exactly the studied dose
- Sizes
- 100 g / 500 g / 1 kg (and larger)
- Testing
- Per-batch, multi-stage third-party testing, cGMP
Pros- 100% plain glycine — no fillers, no blend, exactly what the studies used
- One scoop is the 3 g studied dose, so there's zero math at bedtime
- Naturally sweet — dissolves clear in water or tea, genuinely pleasant
- Lowest cost per gram on the list; a 1 kg bag lasts roughly a year at 3 g/night
Cons- Bulk bag means you measure your own scoop (a small scoop is included, but it's a no-frills bag)
- Plain warehouse packaging — you're paying for the glycine, not the label
Our take — For the glycine sleep dose specifically, this is the one to buy. It's 100% plain glycine, a single scoop is the studied 3 g, the per-batch third-party testing is exactly what you want from a commodity ingredient, and the cost per dose is the lowest here by a wide margin. Glycine is naturally sweet, so it's pleasant in water — no flavoring, no fillers. The only 'downside' is that it's a no-frills bulk bag, which is the entire point. If you're at all willing to mix a powder, start here.
- #2Best value
Nutricost Glycine Powder
Nutricost · 100% plain glycine powder, scoop included9.1/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.0
- Third-party testing25%8.6
- Dose accuracy (3 g)20%9.6
- Taste & mixability15%8.8
- Value (per 3 g dose)15%9.6
Same plain-glycine, same 3 g scoop, from a popular value brand — with the measuring scoop included in the tub. A near-tie with #1.
- Form
- Plain glycine powder (unflavored)
- Per serving
- 3 g of free-form glycine (scoop included)
- Size
- 1 lb (≈ 150 servings)
- Testing
- ISO-accredited lab, GMP-compliant, FDA-registered facility
Pros- Plain glycine, non-GMO, gluten-free — and an included scoop that measures the 3 g dose for you
- Third-party tested by independent ISO-accredited labs
- Tub packaging is a little more user-friendly than a bulk bag
- Cost per dose is essentially tied with the #1 pick
Cons- Marginally pricier per gram than the largest bulk bags
- Sold mainly in the 1 lb size — heavy nightly users will reorder more often
Our take — Nutricost is the easygoing value pick and a genuine near-tie with BulkSupplements. You get 100% plain glycine, a 3 g scoop that's actually included in the tub, and independent ISO-lab testing — all at a cost per dose within a rounding error of #1. The only reasons it sits at #2 are slightly higher cost per gram than the biggest bulk bags and a smaller default size. If a measuring scoop in a tidy tub is worth a hair more to you than the absolute lowest price, buy this instead of #1 and you've lost nothing that matters.
- #3Best powder (household brand)
NOW Foods Glycine Pure Powder
NOW Foods · 100% pure glycine powder, 1 lb (454 g)8.9/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.0
- Third-party testing25%8.8
- Dose accuracy (3 g)20%8.6
- Taste & mixability15%9.0
- Value (per 3 g dose)15%9.2
Pure glycine powder from a household name with decades of in-house QC. The trusted, widely-stocked powder — the easy offline backup.
- Form
- Pure glycine powder (unflavored)
- Label serving
- 1/4 tsp ≈ 1 g (use ~1 rounded tsp for the 3 g sleep dose)
- Size
- 1 lb (454 g)
- Testing
- NOW in-house analytical labs, GMP, widely audited
Pros- Household-name brand with one of the most respected in-house QC operations in the industry
- Pure glycine, vegan, non-GMO, naturally sweet and easy to mix
- Stocked in most health stores — the simplest offline backup if you run out
- Strong value, just edged out by the bulk-bag specialists
Cons- Label serving is 1 g (1/4 tsp) — you measure ~1 rounded tsp yourself for the 3 g sleep dose
- Slightly higher cost per gram than the bulk-bag picks above
Our take — If you'd rather buy a name you already recognize — and be able to grab a bottle at a local store — NOW Foods is the powder to get. The glycine is pure, the in-house QC pedigree is excellent, and it mixes and tastes just like the bulk options. The only practical nuance is that NOW lists the serving at 1 g, so for the studied sleep dose you'll measure roughly a rounded teaspoon (3 g) yourself. It loses to #1 and #2 only on cost per gram and a built-in 3 g scoop, not on quality.
- #4Best tested / best capsules
Thorne Glycine
Thorne · plain glycine capsules, 1 g per capsule, 250 caps8.6/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.5
- Third-party testing25%9.8
- Dose accuracy (3 g)20%8.8
- Taste & mixability15%7.0
- Value (per 3 g dose)15%6.6
The most trusted testing pedigree in the category, in a 1 g capsule — so the 3 g dose is three caps, not six. The convenience pick when verification is the priority.
- Form
- Plain glycine capsules (1 g each)
- Per serving
- 3 g = 3 capsules (label suggests 2 caps, 1-3× daily)
- Bottle
- 250 capsules (125 × 2-cap servings)
- Testing
- Third-party certified; trusted by 100+ pro sports teams
Pros- Best-in-class testing and QC reputation — third-party certified, clinician- and athlete-trusted
- 1 g per capsule means the 3 g dose is just three capsules (most capsule brands need six)
- Plain glycine with a clean, minimal excipient profile
- Convenient and travel-friendly — no scooping or mixing
Cons- Costs several times more per gram than any of the powders
- Capsules sidestep glycine's natural sweetness — you lose the pleasant-drink upside
Our take — If you want capsules instead of powder, Thorne is the one to beat — the testing pedigree is the best here, it's a brand clinicians and pro teams actually rely on, and crucially it's a 1 g capsule, so hitting the 3 g dose takes three caps rather than six. The trade-off is inherent to capsules: you pay several times the powder price per gram, and you forfeit glycine's nice natural sweetness in a drink. For travel, convenience, or maximum testing assurance, it's an easy call; for pure cost-efficiency at home, a powder still wins.
- #5Best clean-label capsules
Pure Encapsulations Glycine
Pure Encapsulations · hypoallergenic plain glycine, 1,500 mg per 3-cap serving, 180 caps8.4/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.5
- Third-party testing25%9.4
- Dose accuracy (3 g)20%8.4
- Taste & mixability15%6.8
- Value (per 3 g dose)15%6.2
The cleanest, most allergen-conscious label here — hypoallergenic plain glycine for sensitive users. The pick when label purity outranks cost and capsule count.
- Form
- Plain glycine capsules (hypoallergenic)
- Per serving
- 1,500 mg per 3 caps (so 3 g = 6 caps)
- Bottle
- 180 capsules (60 × 3-cap servings)
- Testing
- Clinician-grade, hypoallergenic, third-party verified
Pros- Among the cleanest labels in supplements — hypoallergenic, free of common allergens and needless excipients
- Clinician-preferred brand with a 30+ year QC reputation
- Plain free-form glycine, vegan and gluten-free
- Ideal for chemically-sensitive users who react to fillers
Cons- 500 mg per capsule means the 3 g sleep dose is six capsules — the most of any pick
- Premium pricing — among the highest cost per gram on the list
Our take — Pure Encapsulations is the pick for one specific buyer: someone who wants the cleanest, most allergen-free label possible and is willing to pay for it. The hypoallergenic formulation and clinician-grade QC are genuinely best-in-class. The catch is purely practical — at 500 mg per capsule, the studied 3 g dose is six capsules a night, and the cost per gram is at the top of the list. If you have allergen sensitivities or simply want the most transparent label, it's worth it; if you just want plain glycine at a fair price, a powder or the 1 g-capsule picks make more sense.
- #6Best budget capsules
Double Wood Glycine
Double Wood · plain glycine capsules, 1,000 mg per capsule, 300 caps8.3/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%8.8
- Third-party testing25%8.0
- Dose accuracy (3 g)20%8.6
- Taste & mixability15%6.8
- Value (per 3 g dose)15%9.2
1,000 mg per capsule, 300 per bottle, third-party tested — the cheapest capsule route to the 3 g dose (three caps). The value option if you want capsules over powder.
- Form
- Plain glycine capsules (1,000 mg each)
- Per serving
- 1,000 mg per capsule (so 3 g = 3 caps)
- Bottle
- 300 capsules (100 × 3-cap doses)
- Testing
- Third-party tested, non-GMO, gluten-free
Pros- 1 g per capsule, so the 3 g dose is just three caps
- 300-capsule bottle = 100 nights of the full 3 g dose — a long-running supply
- Cheapest cost per gram of any capsule here
- Plain glycine, third-party tested, non-GMO and gluten-free
Cons- Testing transparency is good but not at the Thorne / Pure Encapsulations tier
- Still costs more per gram than any of the powders
Our take — If you've decided on capsules and value is your priority, Double Wood is the answer. A 1,000 mg capsule keeps the 3 g dose to three caps, the 300-count bottle lasts about 100 nights, and the per-gram cost is the lowest of any capsule on the list. You give up a little of the elite testing pedigree you'd get from Thorne or Pure Encapsulations, but for plain, third-party-tested glycine in convenient capsules at the best capsule price, it's the smart budget buy. Powder is still cheaper per gram if you'll mix it.
- #7Best premium-brand single cap
Life Extension Glycine
Life Extension · plain glycine capsules, 1,000 mg each, 100 capsSAC Product Score™ — how it breaks down- Purity & form25%9.0
- Third-party testing25%8.4
- Dose accuracy (3 g)20%7.8
- Taste & mixability15%6.8
- Value (per 3 g dose)15%7.0
A 1,000 mg single-cap glycine from a QC-respected brand with a COA — but a 100-count bottle covers only ~33 nights at the full 3 g dose.
- Form
- Plain glycine capsules (1,000 mg each)
- Per serving
- 1,000 mg per capsule (so 3 g = 3 caps)
- Bottle
- 100 capsules (~33 nights at the 3 g dose)
- Testing
- Life Extension QC, Certificate of Analysis available
Pros- 1 g per capsule keeps the 3 g dose to three caps
- Life Extension's QC pedigree is among the most respected in the industry, with a COA
- Plain glycine, vegetarian, non-GMO, gluten-free
- Brand explicitly positions glycine for healthy sleep — straightforward labeling
Cons- 100-count bottle is small — only ~33 nights at the full 3 g dose, so you reorder often
- Cost per gram is higher than Double Wood for the same 1 g-capsule format
Our take — Life Extension makes a perfectly good 1 g glycine capsule, and the brand's QC reputation and published COA give it real credibility. The reason it sits at #7 rather than higher is pure economics: the bottle is only 100 capsules, which is about 33 nights at the 3 g sleep dose, and the cost per gram lands above Double Wood's near-identical format. If you're already a Life Extension loyalist and want a single-cap glycine with a strong QC story, it's a fine choice — but for the same capsule format at a better price, Double Wood (#6) wins, and any powder beats it on value outright.
- #8Trusted brand (smallest cap dose)
Solgar Glycine 500 mg
Solgar · plain free-form glycine, 500 mg per capsule, 100 veg caps7.6/10SAC Product Score™SAC Product Score™ — how it breaks down- Purity & form25%9.0
- Third-party testing25%8.2
- Dose accuracy (3 g)20%6.6
- Taste & mixability15%6.8
- Value (per 3 g dose)15%6.4
A legacy, heritage-brand free-form glycine — clean and trustworthy, but at 500 mg per capsule the 3 g sleep dose means swallowing six, in a 100-count bottle.
- Form
- Plain free-form glycine capsules
- Per capsule
- 500 mg (so 3 g = 6 caps)
- Bottle
- 100 vegetable capsules (label dose: 1 cap 2×/day)
- Testing
- Solgar Gold Standard QC, non-GMO, vegan, kosher
Pros- Heritage brand with a long-standing Gold Standard QC reputation
- Plain free-form L-glycine — clean, non-GMO, vegan, kosher
- Quality and purity of the glycine itself are not in question
- Good fit for someone who only wants Solgar's smaller label dose (500 mg-1 g)
Cons- At 500 mg per capsule, the studied 3 g sleep dose is six capsules a night
- 100-count bottle plus 6-caps-per-dose means it empties in ~16 nights at the full dose
- Among the highest cost per 3 g dose on the list
Our take — Solgar is a trustworthy, heritage brand and the glycine itself is clean free-form L-glycine — this is not a quality knock. It ranks last purely on fit for the sleep use case: at 500 mg per capsule, hitting the studied 3 g dose means six capsules every night, and a 100-count bottle disappears in roughly two weeks at that rate, which makes it both inconvenient and expensive per dose. If you specifically want Solgar and you're using glycine at a smaller daily amount, it's perfectly good. For the 3 g sleep dose, a powder (#1-#3) or a 1 g capsule (#4, #6, #7) is the better tool.
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Glycine for Sleep: One Amino Acid, One Dose, and an Honest Amount of Evidence
- 01
Glycine is a single ingredient with a single studied dose.
Unlike magnesium, where the form is everything, glycine for sleep is roughly 3 g of plain glycine taken 30-60 minutes before bed. So the variables that separate one bottle from another aren't exotic: purity, third-party testing, how cleanly a serving hits 3 g, taste, and cost per dose.
- 02
The evidence is moderate, not strong — and we say so up front.
It rests on a small cluster of studies, most with only about 10-20 subjects and most from a single research group. Within that limit the signal is real and fairly consistent, but glycine is a gentle, well-tolerated aid with a plausible mechanism — not a sedative, and not a substitute for fixing your sleep schedule.
- 03
What the signal actually is: easier sleep onset and fewer wrecked mornings.
About 3 g before bed improved subjective sleep quality and, on polysomnography, shortened the time to fall asleep and to reach deep slow-wave sleep (Yamadera 2007). It also reduced next-day fatigue, sleepiness, and reaction-time lapses after a deliberately shortened night (Bannai 2012). The proposed mechanism — glycine lowering core body temperature via NMDA receptors — comes from a rat study (Kawai 2015).
- 04
Buy plain glycine, and for the 3 g dose, powder usually wins.
Every blend was disqualified — magnesium glycinate is a magnesium product, NAC+glycine is a glutathione product, and vague 'complex' tubs bury the dose. Powders top the ranking because the 3 g dose is trivial to scoop and dirt-cheap per gram; capsules earn their place purely on convenience.
Three glycine sleep studies — Bannai 2012 (PMID 22529837), Kawai 2015 (PMID 25533534), and the canonical Yamadera 2007 PSG study (no PMID). Full scoring in the methodology below.
How we ranked these eight
Each pick was scored 0-10 across five criteria, then weighted to a final composite. Purity and third-party testing carry the most weight (25% each) because glycine is a commodity ingredient — the entire job is making sure you're getting clean, verified, plain glycine and not a blend or an untested powder. Dose accuracy (20%) rewards products that let you hit the studied 3 g dose cleanly: a 3 g powder scoop or a 1 g capsule beats a 500 mg capsule that forces you to swallow six. Taste and mixability (15%) is a real factor here and a rare case where the ingredient helps itself — glycine is naturally sweet, so a good powder is pleasant in water or tea, while capsules sidestep taste entirely. Value (15%) is cost per 3 g dose, where glycine's rock-bottom price means bulk powder usually wins decisively. We do not invent numbers; the only clinical figures we cite are the published glycine sleep studies, and we flag their small size honestly.
- Purity & form (plain glycine, no fillers)25%
Is it 100% plain glycine, or is it cut with fillers or sold as a blend? Plain, free-form glycine scores highest; anything labeled 'complex,' NAC+glycine, or magnesium glycinate is disqualified outright because the sleep evidence is for glycine by itself. Minimal, necessary capsule excipients are fine and lightly noted.
- Third-party testing / quality25%
Per-batch third-party testing, a public COA, ISO-accredited labs, or third-party certification (e.g. Thorne's) score highest; a GMP-certified, FDA-registered facility is the baseline. Because glycine is a cheap commodity, verification is the main thing separating a trustworthy powder from an anonymous one.
- Dose accuracy (3 g target)20%
How cleanly can you hit the studied ~3 g pre-bed dose? A powder where one scoop equals 3 g, or a 1,000 mg capsule (three caps), scores highest. A 500 mg capsule (six caps for 3 g) is penalized for the swallow burden, even if the glycine itself is fine.
- Taste & mixability15%
Glycine is naturally sweet, which is a genuine advantage for powders — they dissolve clear and taste pleasant in water or tea, no flavoring needed. Powders that mix cleanly score highest. Capsules are scored neutral-to-good here: they avoid taste entirely, which suits people who don't want to mix anything.
- Value (cost per 3 g dose)15%
Price divided by the number of 3 g doses in the package. Glycine is one of the cheapest amino acids made, so bulk powder lands at a few cents per dose and capsules cost several times more per gram. Tie-breaker — purity and testing do most of the ranking, but value is decisive between otherwise-equal picks.
The bottom line
- 01
The answer: BulkSupplements Glycine Powder (#1).
It is 100% plain glycine, one scoop is the studied 3 g dose, it is per-batch tested, and it has the lowest cost per gram in the category. If you are at all willing to mix a powder, start here.
- 02
Every buyer has a clear runner-up, at its own rank.
Nutricost (#2) is a near-tie with a scoop in the tub; NOW Foods (#3) is the trusted household-name powder. If you'd rather take capsules, Thorne (#4) has the best testing in a 1 g cap, Pure Encapsulations (#5) is the cleanest allergen-free label, and Double Wood (#6) is the cheapest capsule route.
- 03
The rule to leave with: plain glycine, 3 g, give it two weeks.
Skip magnesium glycinate, NAC+glycine, and vague 'complex' tubs — the sleep evidence is for glycine by itself. Take 3 g, 30-60 minutes before bed, and stack it with good sleep timing and a cool room. Glycine is a small, well-tolerated edge, not a cure.
Every claim ranked above traces back to one of these
The clinical research and verified product specs behind the picks. Studies link to their abstract on PubMed; product specs link to the manufacturer's listing.
- [1]Bannai 2012
The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers
In healthy volunteers whose sleep was restricted to 75% of normal for three nights, 3 g of glycine before bed significantly reduced subjective daytime fatigue and sleepiness and improved psychomotor vigilance (reaction-time) performance versus placebo. The best-replicated glycine sleep finding — but a small study, and the benefit appeared mainly on the first restricted day. Authors are affiliated with Ajinomoto, a glycine manufacturer (noted for transparency).
- [2]Kawai 2015
The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus
Mechanistic study in rats: oral glycine promoted sleep and lowered core body temperature by acting on NMDA receptors in the suprachiasmatic nucleus (the master circadian clock), increasing cutaneous blood flow and heat loss; ablating the SCN abolished the effect. Provides the leading biological explanation for glycine's sleep effect — but it is an animal study, so extrapolation to humans is indirect.
- [3]Yamadera 2007
Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes
In volunteers with chronic unsatisfactory sleep, 3 g of glycine before bed improved subjective sleep quality and sleep efficacy and, on polysomnography, shortened latency to sleep onset and to slow-wave sleep without altering overall sleep architecture. The canonical human glycine-sleep study and the source of the 3 g dose — but small (~11 subjects), from the Ajinomoto group, and published in a journal that PubMed does not index, so no PMID is available. Cited honestly without a fabricated identifier; PMID to verify only if the journal is ever indexed.