L-theanine for sleep: what it is and what the research says
L-theanine is an amino acid found naturally in tea leaves. It's one of the reasons a cup of green tea can feel calm rather than jittery. As a supplement, people use it at night because it supports relaxation and sleep quality without making you feel sedated.*
What is L-theanine?
L-theanine is a non-protein amino acid found mainly in the tea plant (Camellia sinensis). Small human studies suggest it may support a relaxed, wakeful state, including increased alpha brain wave activity, which is linked to calm alertness. [1]
What does the research say about sleep?
- A 2019 randomized, placebo-controlled trial in healthy adults gave 200mg of L-theanine daily for 4 weeks and found improvements in several sleep quality measures, including sleep latency and sleep disturbance scores, versus placebo. [2]
- A review of studies on L-theanine and sleep concluded it may support sleep quality, likely by promoting relaxation rather than acting as a sedative. [3]
- Research is still limited. Most studies are small and short, so more work is needed.
How much L-theanine do people take for sleep?
Studies on sleep have commonly used 200mg a day. [2][3] Knocked Sleep Support contains 200mg per serving. Talk with your doctor before starting any supplement, especially if you are pregnant, nursing, or take medication.
L-theanine vs melatonin
Melatonin is a hormone that signals timing to your body clock. L-theanine is an amino acid that supports relaxation.* They work in different ways. If you'd rather skip melatonin, L-theanine is one of the most common ingredients in melatonin-free formulas.
Why we pair it with magnesium, GABA and apigenin
Knocked Sleep Support is a melatonin-free formula. Each serving contains: | Ingredient | Amount | |---|---| | L-theanine | 200mg | | Magnesium (as magnesium glycinate) | 110mg elemental | | GABA | 100mg | | Apigenin | 50mg |
Together they're designed to support relaxation at bedtime and restful sleep.* Knocked Sleep Support launches in mid-January 2027. See Knocked Sleep Support
FAQ
Does L-theanine make you drowsy? It's not generally described as a sedative. Studies suggest it supports a relaxed but alert state, which may make it easier to wind down.* [1][3] When should I take it? Many people take it 30 to 60 minutes before bed. Follow the directions on your product label. Can I take L-theanine every night? Studies have used daily doses for several weeks. [2] Ask your doctor what's right for you.
Waking up in the middle of the night? Read Why do I wake up at 3am?
Sources
- Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. 2008;17 Suppl 1:167-168. https://pubmed.ncbi.nlm.nih.gov/18296328/
- Hidese S, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. https://pubmed.ncbi.nlm.nih.gov/31623400/
- Rao TP, et al. In Search of a Safe Natural Sleep Aid. J Am Coll Nutr. 2015;34(5):436-447. https://pubmed.ncbi.nlm.nih.gov/25759004/
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.