Supplement · Grade B

Glycine and medications.

Every documented pair, every citation. Below: 1 documented pair grouped by mechanism.

Glycine is in the Distil supplement database, evidence Grade B. The page below lists every medication we have explicitly assessed it against.

Glycine is the simplest amino acid, and its main supplement use is sleep quality, where it appears to work by modulating NMDA receptors and lowering core body temperature before sleep. The evidence is Grade B: Bannai's RCT showed 3g before bed reduced fatigue and improved next-day performance after restricted sleep, though the trial base is smaller than for Grade A compounds, so the claim is owed that context. It also contributes to collagen synthesis and, paired with NAC, to glutathione. The usual sleep dose is 3 to 5g before bed. One stacking point matters more than any drug interaction: if magnesium glycinate or collagen peptides are already in your routine, both deliver substantial glycine themselves, so the standalone dose should sit at the lower end to avoid stacking unnoticed. It is very well tolerated, with mild sedation being the point rather than a side effect.

Below are the 1 documented pair we have explicitly assessed for Glycine: 1 amber. The pairs cluster around 1 mechanism: Reduced antipsychotic effect. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.

Documented interactions

Reduced antipsychotic effect

Amber Clozapine

High-dose glycine taken alongside clozapine may work against the clozapine, making it less effective at controlling psychotic symptoms. This was seen in studies using very large glycine doses (30 to 60 grams a day), far above a typical glycine supplement. If you take clozapine, it is best not to add high-dose glycine, and to discuss any glycine supplement with the team that manages your medication, because clozapine is closely monitored.

PMID 9892314 · PMID 10784481 · BNF: Clozapine

What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.

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For adults over 18. This tool gives evidence-graded information, not medical advice. Always discuss changes with your GP, especially if you take any medication, are pregnant, breastfeeding, or have a serious health condition.

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Distil's interactions database is reviewed and updated every quarter. We grade evidence transparently and publish our methodology, including every database change, at /about/methodology. This tool is information, not a substitute for clinical judgement. If you take medication and supplements together, your GP or pharmacist can review your full regimen against your medical history. If you want a full personalised stack reasoned against this same database, the Distil report is the next step up.