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No. 017supplement

Glycine

Glycine is a supplement that is sold over the counter.

Also known as Aminoacetic acid

Glycine is the smallest amino acid and plays a role in body temperature regulation and nerve signaling. A handful of small Japanese studies suggested it might improve sleep quality and next-day alertness.

In 1 example journal

An unbranded white supplement container tipped over beside a clear scoop of cocoa-toned powder on a beige surface.
Over the counter

Is Glycine FDA-approved?

Sold without a prescription. Supplements are not reviewed by the FDA before sale, so third-party testing matters. Sold as a dietary supplement and food ingredient.

As of September 23, 2026.

Key takeaways

  • Glycine is the simplest amino acid. Your body makes it, and it is in protein-rich foods.
  • A few small studies suggest it may improve sleep quality and next-day alertness.
  • A 2026 review found only three sleep trials, so the evidence is thin.
  • It is generally well tolerated.

How does Glycine work?

Glycine acts as a calming signal in the brain and spinal cord. In rat studies, it acted on the brain's master clock and lowered core body temperature, one of the body's natural cues for sleep.

Researchers think that small drop in body temperature may explain the better sleep reported in human studies.

An unbranded white supplement jar beside a clear scoop of pink powder spilling out on a warm beige background.
A bright, pastel-toned bedroom corner with a bedside lamp glowing beside a neatly made striped bed.
A minimalist bright bedroom nightstand at dusk with a glowing white lamp and a pale blue ceramic knot sculpture, no people or text visible.

What does the evidence say about Glycine?

Emerging evidence

Only a few small, short studies in healthy volunteers, several industry-sponsored.

What to expect

What trials and prescribing information measured over time. Everyone responds differently.

  1. A few nights

    The 2012 trial measured effects over three nights of restricted sleep.

What do clinicians say about Glycine?

Glycine is low-risk, but the sleep evidence rests on a handful of small studies.

Summaries of published guidelines, drug labels, regulators and reviews, each attributed to its source. DiscoverMedica does not employ clinicians.

Is Glycine right for you, and who should avoid it?

Often considered for

  • Adults curious about a low-risk sleep supplement, after ruling out sleep disorders

Not a fit, or needs extra care

  • People taking the antipsychotic clozapine, without medical advice
  • Pregnancy or breastfeeding: not well studied

Only a licensed clinician who knows your history can decide whether it is right for you.

What are the risks and side effects of Glycine?

  • Generally well tolerated; mild stomach upset is possible.
  • It may reduce the effect of the antipsychotic clozapine; do not combine without medical advice.
  • Not well studied in pregnancy or breastfeeding.

What should you ask a clinician about Glycine?

  • Is there an underlying sleep disorder I should rule out?
  • Could it interact with any of my medications?

These save with the compound when you add it to My Journal, so they’re on the printout for your visit.

How do people buy Glycine?

An overhead array of several ceramic bowls and dishes holding unbranded capsules, softgels and tablets on a light surface.

  1. No prescription is needed. Supplement brands and retailers sell it online and in stores.

  2. Check with a clinician or pharmacist first if you take prescription medication or have a chronic condition.

  3. Choose a product with independent testing, such as NSF Certified for Sport or USP Verified, because FDA does not check supplements before they are sold.

Where some people buy it

  • ThorneSells glycine capsules direct to consumers.
  • iHerbCarries glycine powder and capsules from many brands.

From each provider’s own site, checked September 23, 2026. Programs change, so confirm the details before you sign up.

Where can I get Glycine?

9 providers list Glycine on DiscoverMedica, lowest listed price first.

Life ExtensionGlycine vegetarian capsules, 100 count
Lowest listed priceNo prescription
$12.00listed price†
Buy at Life Extension
NOW FoodsGlycine Pure Powder, 1 lb
No prescription
$29.99listed price†
Buy at NOW Foods
ThorneGlycine, 250 capsules
No prescription
$31listed price†
Buy at Thorne
Pure EncapsulationsGlycine
No prescription
$35listed price†
Buy at Pure Encapsulations
AmazonGlycine (multiple brands)
No prescription
see site
Buy at Amazon
GNCGlycine (multiple brands)
No prescription
see site
Buy at GNC
iHerbGlycine (multiple brands)
No prescription
see site
Buy at iHerb
TargetGlycine (multiple brands)
No prescription
see site
Buy at Target
WalmartGlycine (multiple brands)
No prescription
see site
Buy at Walmart

† Prices as listed by the provider when we checked; they change.

Glycine: questions, answered

Does glycine really help sleep?

A few small studies say it may. The evidence is too limited to be confident.

Is it safe?

Glycine is generally well tolerated, with mild stomach upset possible. It may interact with clozapine.

Can I get it from food?

Yes. Meat, fish, dairy and gelatin all contain it.

Can I get it through telehealth?

It does not need a prescription. You buy it from supplement brands and retailers.

Important safety information

Key risks

  • Generally well tolerated; mild stomach upset is possible.
  • It may reduce the effect of the antipsychotic clozapine; do not combine without medical advice.
  • Not well studied in pregnancy or breastfeeding.

Talk to a clinician first, or avoid it, if

  • People taking the antipsychotic clozapine, without medical advice
  • Pregnancy or breastfeeding: not well studied

This is not a complete list of risks. Talk to a licensed clinician or pharmacist about your own situation. If you have a severe reaction, call 911. You can report side effects to the FDA through MedWatch at 1-800-FDA-1088.

Sources

Also checked for this guide

Guide reviewed September 23, 2026.

Educational information only, not medical advice. It does not replace a conversation with a licensed clinician.

Example journals

Journals with Glycine.

A bright, clean bedroom corner at evening with a black table lamp glowing softly on a white nightstand beside a bed with blue and white pillows.
Marcus
Personal list
Example

My sleep reset

Starting with the gentle, well studied stuff before anything stronger.

Magnesium glycinateGlycineMelatoninL-theanine
Same goal

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A gentle form of magnesium that people take for sleep and relaxation.

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DSIP

peptide

A 1970s "sleep peptide" sold online. Human results were inconsistent and it is not approved.

Research onlyAnimal & lab studies only
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