Can You Take Glycine and L-Theanine Together?

Use extra care with this pair

The short answer

Both Glycine and L-Theanine promote relaxation and improve sleep quality through different inhibitory mechanisms. Stacking both may cause excessive sedation, especially when taken before sleep.

How to arrange timing

Start with low doses of each when combining Glycine and L-Theanine for sleep. Reduce doses if excessive drowsiness occurs.

Reference

Reference noted for this combination: Inagawa K, et al. Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep Biol Rhythms. 2006;4(1):75-77.

Important context

Whether supplements suit you together also depends on dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.