Ingredient Spotlight — L-Theanine (Suntheanine®) · PM Formula

Quiet the Mind

The thing standing between you and good sleep usually isn't your body — it's a mind that won't stop narrating. A four-week human trial measured what L-theanine does to sleep quality and the sense of being wound-too-tight.

You know the feeling of lying down exhausted and finding your head still going — replaying the day, pre-playing tomorrow. L-theanine, the amino acid that gives green tea its calm-without-drowsy character, has long been associated with a settled, alert-but-relaxed state. This study asked whether four weeks of it meaningfully changes how you sleep and how wound-up you feel.

The trial

In a randomized, placebo-controlled, double-blind crossover study, 30 healthy adults took L-theanine (Suntheanine®, 200 mg/day) or placebo for four weeks each. Sleep quality was measured with the validated Pittsburgh Sleep Quality Index (PSQI), alongside stress-related and cognitive measures.

What they found

• Better sleep quality. PSQI sleep scores improved significantly after L-theanine versus baseline.
• The right parts of sleep. Compared with placebo, L-theanine improved the PSQI subscales for sleep latency, sleep disturbance, and use of sleep medication — the specific problems that keep a busy mind up.
• Sharper by day, too. Verbal fluency and executive-function scores improved after L-theanine — the daytime dividend of better-quality nights.

The authors concluded L-theanine "has the potential to promote mental health in the general population with stress-related ailments and cognitive impairments" — in a healthy population, at a real-world dose, with no adverse events.

Not sedation. A quieter mind, so sleep can do what it already knows how to do.

Why it's in the PM formula

Suntheanine® is the L-theanine our nighttime formula is built on — the same branded material and 200 mg dose studied here. It quiets the mental chatter that delays sleep, and it pairs with PharmaGABA® to lower the day's stress load: two calming actives working the same wind-down, with human data behind each.

Reference: Hidese S, Ogawa S, Ota M, 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. doi:10.3390/nu11102362.
Read it: pubmed.ncbi.nlm.nih.gov/31623400

*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.