L-Theanine

What it is

L-Theanine is an amino acid that occurs naturally in green tea (Camellia sinensis). It is one of the fastest-rising actives in the Formulation Index, driven by calm, focus and sleep-support briefs. Unlike sedative ingredients, theanine is associated with relaxed alertness, which is why it appears in daytime nootropics as often as night-time blends.

Forms and sourcing

Supplement-grade L-theanine is produced by fermentation to a purity of 98%+ and supplied as a fine white powder. Branded forms such as Suntheanine are available where a brief calls for ingredient-level clinical backing. It is highly soluble with a clean, slightly sweet taste, making it easy to use in powders and stick packs as well as capsules.

Benefits and evidence

Human studies on L-theanine focus on subjective calm, sleep quality and attention, most notably in combination with caffeine, where the pairing is studied for smoothing the stimulant curve. Typical study doses sit between 100 mg and 400 mg. Evidence is promising rather than conclusive, and formulations should be positioned accordingly.

Typical dosage and formats

Most briefs specify 100–200 mg per serving, with 200 mg the most common single dose; caffeine pairings often run 2:1 theanine to caffeine. Theanine is stable through compression and encapsulation and survives gummy processing well, so it suits capsules, tablets, powders, stick packs and gummies alike.

UK and EU regulatory position

L-Theanine is an established food ingredient in the UK and EU and is not a novel food when produced to standard specifications. There are currently no authorised EFSA health claims for L-theanine, so on-pack claims cannot attribute relaxation or focus effects to the ingredient itself; compliant products rely on brand positioning, or on pairing theanine with actives that do carry authorised claims, such as vitamin B6 or magnesium. Our technical team structures the claims strategy during formulation.