Glycine

Glycine is the simplest amino acid and serves multiple functions in human physiology, with research indicating particular promise for sleep quality and metabolic health. Studies suggest that glycine supplementation before bedtime may improve sleep quality by acting as an inhibitory neurotransmitter in the brain, helping to lower core body temperature and reduce sleep onset time. The typical research dosage ranges from 3 grams taken 30 minutes before bedtime.

Beyond sleep benefits, research indicates glycine may support metabolic health through effects on glucose metabolism and insulin sensitivity. Some studies suggest it could help reduce inflammation and support collagen synthesis, though these areas require further investigation. The amino acid is naturally present in protein-rich foods like meat, fish, and gelatin, but therapeutic doses typically require supplementation.

Glycine appears to have an excellent safety profile with minimal reported side effects, making it an attractive option for those seeking natural sleep support. Research suggests it's well-tolerated even at doses several times higher than typical supplementation amounts, though some individuals may experience mild gastrointestinal effects. As a naturally occurring amino acid, glycine is widely available as an over-the-counter supplement in most countries.