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glycine

Glycine is a dietary supplement.

Generic

Not yet rated· sourced from the FDA label
Rated against independent regulatory sources·Last updated June 23, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass
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Key facts

Active ingredient
Glycine
Form
Irrigant, Solution
Type
Supplement

What the evidence says

Limited evidence

What Glycine is

Glycine is the smallest amino acid and one of the building blocks the body uses to make proteins. The MedlinePlus Medical Encyclopedia (National Library of Medicine, NIH) lists it among the "nonessential" amino acids, meaning the body can normally produce it on its own, and also lists it as "conditionally essential," meaning the need for it may increase during illness or stress. Glycine is also sold as a standalone dietary supplement, typically as a powder or capsule.

Commonly used for

Marketed by sellers for sleep qualityPromoted for general wellness or recoveryTaken as a supplemental source of dietary amino acidsUsed by some people for exercise- or performance-related goals

What the evidence shows

Rigorous evidence from US government health authorities is limited. The NIH Office of Dietary Supplements (ODS) and the National Center for Complementary and Integrative Health (NCCIH) do not publish a dedicated consumer fact sheet evaluating glycine as a supplement, and the MedlinePlus encyclopedia describes glycine only as a normal dietary amino acid rather than assessing any supplement claims. Because no authoritative federal consumer review establishes specific benefits, any claim that glycine treats, cures, prevents, or improves a health condition should be treated as unproven.

Typical dosage

There is no government-established recommended supplement dose for glycine, since the body normally makes its own and it is also obtained from protein-containing foods. Amounts used in commercial products and in studies vary widely, so do not assume that more is better. Talk to your doctor, pharmacist, or another qualified clinician before starting glycine, especially if you are pregnant or breastfeeding, have a medical condition, or take prescription medicines.

Safety

Glycine occurs naturally in the diet and in the body, but the federal sources reviewed here do not provide a formal safety assessment of glycine taken as a concentrated supplement, so its long-term safety at supplement doses is not well characterized by these authorities. People who are pregnant or breastfeeding, who have kidney or liver conditions, or who take prescription medicines should be especially cautious and consult a clinician first. Dietary supplements are not reviewed by the FDA for safety and effectiveness the way prescription medicines are.

Side effects

The government sources reviewed here do not catalog specific side effects of glycine supplements, so no authoritative federal side-effect profile is available. As with many supplements, taking concentrated amounts could in principle cause mild digestive upset in some people, though this is a general caution rather than a documented federal finding. Stop use and seek medical advice if you have an unexpected reaction.

Interactions & cautions

No drug or supplement interactions for glycine are documented in the US government sources reviewed here, which does not mean none exist. To be safe, tell your doctor or pharmacist about all medicines and supplements you take so they can check for possible interactions before you add glycine.

Sources

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Summarized from public health authorities; general reference, not medical advice. Talk to a licensed healthcare professional before starting any supplement.

Dosage forms

Irrigant and Solution

The forms currently marketed in the U.S., per the FDA National Drug Code Directory.

Ways to save

Ask for the generic

Same active ingredient, far cheaper. Is there a generic? →

Request a 90-day supply

Bulk fills usually lower the per-dose price vs monthly refills.

Use copay cards

Manufacturer copay cards & patient-assistance programs — especially for brand drugs.

Compare alternatives

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Frequently asked questions

What forms does Glycine come in?
Glycine is currently marketed as irrigant and solution, per the FDA's National Drug Code Directory.

Information is sourced from public FDA regulatory data. Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

What people report to the FDA about Glycine

The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 2,434 reports naming Glycine, and the FDA flagged 79% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:

  • nausea163 reports
  • fatigue134 reports
  • diarrhoea130 reports
  • dyspnoea124 reports
  • headache124 reports
  • dizziness112 reports
  • pneumonia100 reports
  • pyrexia92 reports

Read these as a signal, not a rate. A report does not mean Glycine caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.

Source: openFDA drug/event (FAERS), retrieved September 25, 2026.

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