L-theanine trial links lower stress and cortisol in people
A double-blind, placebo-controlled, crossover trial in people found that an L-theanine drink reduced self-reported stress and cortisol during a cognitive stressor. Alpha brain activity rose only in people with higher anxiety.
Source: L-theanine trial links reduced stress response and cortisol in people (x.com). Summary written with AI from the source and reviewed by rules; read the original.
What the research shows
The trial tested an L-theanine drink in people against a placebo, using a crossover design in which the same participants go through both conditions. During a cognitive task used as a stressor, the L-theanine drink was associated with lower stress reported by participants and lower cortisol, a hormone linked to the stress response. Alpha brain activity also increased, but only in people with higher anxiety.
The double-blind design, in which neither participants nor researchers knew who received the substance, and the use of a placebo help reduce bias. Even so, a single trial is usually an early step, and the report alone cannot confirm the effect across the wider population. The results also depend on a controlled stress situation, which may not reflect everyday life.
What it means
The finding suggests that L-theanine may be associated with a smaller stress response in a test situation, with both hormonal and brain signals. It is still unknown whether this effect holds for other people, in other settings, or over longer periods.
How to read it with care
This result does not replace a consultation. Anyone considering a change in diet, supplements or treatment should talk to a doctor or another qualified health professional.