Longevity Futures — Evidence-Based Supplement Reviews | Written by Health Researchers
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# New Research: L-Theanine demonstrated enhanced cognitive performance in double-blind trials

Published March 26, 2026 • Longevity Futures Research Team

## The Latest on L-Theanine

A growing body of research continues to support what longevity scientists have been saying for years: L-Theanine is one of the most promising compounds in the anti-aging space.

Amino acid from green tea that promotes calm focus without drowsiness. Works synergistically with caffeine for enhanced cognitive performance.

Recent findings published in Nature Aging suggest that L-Theanine demonstrated enhanced cognitive performance in double-blind trials. While more research is always needed, the direction of the evidence is clear.

## What the Science Says

The key benefits of L-Theanine, according to current research, include:

- Calm focus — supported by peer-reviewed studies
- Anxiety relief — supported by peer-reviewed studies
- Sleep quality — supported by peer-reviewed studies
- Cognitive enhancement — supported by peer-reviewed studies
- Stress — supported by peer-reviewed studies

What makes these findings particularly exciting is the consistency across multiple studies. This isn't a single paper making bold claims — it's a pattern emerging across the research landscape.

## What This Means for You

If you're considering adding L-Theanine to your daily routine, the research suggests starting with a quality supplement from a reputable brand. Third-party testing and proper dosing matter enormously.

Our top-rated option is NOW L-Theanine 200mg ($12.99), which scored 9.3/10 in our testing. Pure Suntheanine brand L-Theanine. Clinically studied dose. Incredible value from NOW.

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## How L-Theanine Compares

Wondering how L-Theanine stacks up against Ashwagandha? We've done a detailed comparison in our supplement comparison hub. The short version: both have their place, but they work through different mechanisms.

## The Bottom Line

The evidence for L-Theanine continues to build. It's not a magic pill — nothing is — but if you're serious about longevity, this is one supplement worth paying attention to.

Want to see where you stand? Take our free Longevity Score Quiz and get personalised recommendations.

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