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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. There is one drug interaction: high-dose glycine may make clozapine less effective, so anyone taking clozapine should discuss any glycine supplement with the team managing that medicine. One stacking point deserves as much attention: 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

Last reviewed 14 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.

Reduced antipsychotic effect

Amber Does interact with 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.

Evidence: Supported by human study data.

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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