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 is one of the simplest things you can take for sleep — the smallest amino acid, naturally sweet, present in food, and one of the cheapest supplements that exists. And unlike magnesium (where the FORM is everything) glycine is a single ingredient with a single studied dose: roughly 3 g of plain glycine, taken 30-60 minutes before bed. So the variables that actually separate one bottle from another aren't exotic. They're purity (is it just glycine, or a blend?), third-party testing, how cleanly each serving lets you hit that 3 g, taste and mixability, and the honest cost per 3 g dose. Here's the part most listicles won't say plainly: glycine's sleep evidence is MODERATE, not strong. It rests on a small cluster of studies — most with only about 10-20 subjects, most from a single research group. Within that limit, the signal is real and fairly consistent: about 3 g of glycine before bed improved subjective sleep quality and, on polysomnography, shortened the time to fall asleep and to reach deep slow-wave sleep (Yamadera 2007); and it reduced next-day fatigue, sleepiness, and reaction-time lapses after a deliberately shortened night (Bannai 2012, PMID 22529837). The proposed mechanism — glycine acting on NMDA receptors in the brain's master clock to lower core body temperature — comes from a rat study (Kawai 2015, PMID 25533534). Translation: glycine is a gentle, well-tolerated sleep aid with a plausible mechanism, not a sedative, and not a substitute for fixing your sleep schedule. With that framing, the ranking gets simple and honest. We disqualified every blend — magnesium glycinate (that's a magnesium product), NAC+glycine (that's a glutathione/longevity product), and vague 'glycine complex' tubs — and ranked eight PLAIN glycine products on the five things that matter: purity and form, third-party testing, dose accuracy against the 3 g target, taste and mixability (glycine's natural sweetness is a genuine plus for powders), and value per 3 g dose. Powders dominate the top because the 3 g dose is trivial to scoop and dirt-cheap per gram; capsules earn their place purely on convenience.
Just tell me what to buy: get the BulkSupplements Glycine Powder (#1) — 100% plain glycine, one scoop is the studied 3 g dose, per-batch tested, and the lowest cost per gram in the category. Want the same dose with a measuring scoop in the tub from a popular value brand: Nutricost Powder (#2). Prefer a household name on the shelf: NOW Foods Pure Powder (#3). If you'd rather swallow capsules than scoop powder, Thorne (#4) has the most trusted testing in a 1 g cap (so 3 g is three caps, not six); Pure Encapsulations (#5) is the cleanest allergen-free label; Double Wood (#6) is the cheapest capsule route. Life Extension (#7) is a solid 1 g-cap option from a QC-respected brand, and Solgar (#8) is fine but its 500 mg cap means six capsules for the 3 g dose. Powder if you care about cost and dose; capsules if you care about convenience.
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
If you've read this far and just want to be told what to buy: the BulkSupplements Glycine Powder (#1) is the overall winner — 100% plain glycine, one scoop is the studied 3 g dose, per-batch tested, and the lowest cost per gram in the category. 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. Life Extension (#7) and Solgar (#8) are solid, trustworthy brands that simply lose on dose-economics — small bottles, and in Solgar's case a 500 mg cap that turns the 3 g dose into six capsules.
Two decisions matter more than which brand you pick. First, buy PLAIN glycine — skip magnesium glycinate (a magnesium product), NAC+glycine (a glutathione product), and vague 'complex' tubs, because the sleep evidence is for glycine by itself at 3 g. Second, be honest with yourself about what glycine is: a GENTLE aid backed by MODERATE evidence from a few small studies. The real, replicated findings are nice but subtle — easier sleep onset on PSG (Yamadera 2007) and, most reliably, less next-day fatigue after a short night (Bannai 2012). The proposed mechanism is a drop in core body temperature (Kawai 2015). Take 3 g, 30-60 minutes before bed, give it one to two weeks, and stack it with good sleep timing, a cool room, and magnesium glycinate — 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.
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