Glycine before bed — the human evidence

Glycine is one of the most ordinary molecules in biochemistry, and its sleep evidence is newer and, on the record located here, sturdier than DSIP's own.

The core human trial

Interventional human Bannai, Kawai, Ono, Nakahara and Murakami (2012) ran a randomized, double-blind, placebo-controlled crossover trial in partially sleep-restricted healthy volunteers: 3 grams of oral glycine before bed, assessed against subjective sleep quality and next-day performance endpoints (PMID 22529837, Frontiers in Neurology). The authors' own synthesis of this research line appears in a 2012 review (PMID 22293292, Journal of Pharmacological Sciences).

Mechanism

Mechanistic Kawai et al. (2015) reported that glycine's sleep-promoting and hypothermic effects are mediated by NMDA receptors in the suprachiasmatic nucleus (SCN) — the brain's master circadian-clock region (PMID 25533534, Neuropsychopharmacology). This is currently the strongest mechanistic anchor located for glycine's sleep action. Separately, Animal oral glycine has been shown to raise extracellular serotonin, but not dopamine, in rat prefrontal cortex (Bannai et al., 2011, PMID 21414089) — a secondary, complementary mechanism line, rat data only, not to be conflated with the human sleep-quality result above.

Dosing and safety

The trial dose above was 3 g before bed. Secondary sources report an EFSA 2012 safety review finding no adverse effects up to 10 g/day, and schizophrenia-adjunct trials using considerably higher doses (28-56 g/day) without serious adverse events reported — both of these safety figures are from secondary sources this research pass and were not independently re-verified against the original EFSA opinion or the original schizophrenia trial papers, so they are stated here as reported, not as independently confirmed.

Glycine's other role: inside Deltaran

Separately from its own sleep action described above, glycine is also the second ingredient — at a fixed 1:10 ratio to DSIP — in Deltaran, the 1998 Russian lyophilized preparation. Whether glycine was included in Deltaran for this independent sleep/NMDA action, as a lyophilization bulking agent, or simply because DSIP's own sequence already contains glycine residues is not established in the primary literature located this pass. Read the full, tiered account on the Deltaran page.