Glycine — Stack & Timing
Educational timing and stacking information based on how Glycine has been studied. Not a prescription. Not medical advice.
This is educational information only. Consult a healthcare provider before starting any supplement.
Stack & Timing Guidance
Educational summary based on how Glycine has been studied and commonly used.
Commonly studied timing
The most consistently studied timing is 30–60 minutes before bed, where 3g glycine has been shown to support sleep quality and reduce core body temperature. Collagen-related applications (connective tissue support) sometimes involve timing around activity, but sleep-focused use dominates the expert and clinical literature.
Dose ranges used in studies
Sleep studies primarily used 3g (3000mg); the GlyNAC RCT and broader therapeutic reviews reference ranges up to 9–15g daily depending on the health outcome studied. Higher doses have been used in metabolic and aging contexts without notable adverse effects reported.
↑ These are ranges from research studies, not personal dosing recommendations. Discuss with a clinician.
Commonly paired with
Together as GlyNAC, these two amino acids are precursors to glutathione synthesis; the combination addresses both glycine and cysteine deficiency seen in aging.
Glycine is the most abundant amino acid in collagen; supplementing both may support connective tissue, skin, and joint health synergistically.
Vitamin C is a required cofactor for collagen hydroxylation and is commonly co-administered with glycine or gelatin in connective tissue protocols.
Both glycine and magnesium are used to support sleep onset and quality; glycine may act via thermoregulatory mechanisms while magnesium influences NMDA receptor activity and relaxation.
Safety & interactions
Glycine is generally recognized as safe (GRAS) by the FDA. Acute doses up to 9g and chronic supplementation up to 15g/day have been studied without significant adverse effects reported in the literature reviewed. Individual tolerance should still be assessed, particularly at higher doses.
- •Clozapine: Glycine may theoretically reduce efficacy by modulating NMDA receptor activity — caution advised in patients on antipsychotics targeting this pathway.
- •Blood sugar-lowering medications: Some evidence suggests glycine may influence insulin sensitivity; individuals on hypoglycemic agents should monitor accordingly.
No absolute contraindications were identified in the reviewed literature. Individuals with kidney disease, those on antipsychotic medications (particularly clozapine), or pregnant/breastfeeding individuals should consult a healthcare provider before supplementing, as data in these groups is limited.