The Claim

L-glutamine supplementation at 0.3 g/kg body weight per day for three weeks in combat-sport athletes does not significantly alter salivary cortisol concentration, despite improving the testosterone-to-cortisol ratio through preservation of testosterone levels.

Source: Supplementation of L-glutamine enhanced mucosal immunity and improved hormonal status of combat-sport athletes

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
54score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

In combat-sport athletes taking 0.3 grams of L-glutamine per kilogram of body weight daily for three weeks, salivary cortisol levels remain unchanged, while the testosterone-to-cortisol ratio increases due to stable testosterone levels.

See the scientific wording

L-glutamine supplementation at 0.3 g/kg body weight per day for three weeks in combat-sport athletes does not significantly alter salivary cortisol concentration, despite improving the testosterone-to-cortisol ratio through preservation of testosterone levels.

Why this might work

L-glutamine strengthens the gut lining, which stops bacterial toxins from entering the bloodstream. This reduces overall body stress, so the stress hormone cortisol doesn’t rise. At the same time, glutamine gives the body the fuel it needs to keep making testosterone, so testosterone levels stay steady. The result is a better balance between testosterone and cortisol without lowering cortisol itself.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Supplementation of L-glutamine enhanced mucosal immunity and improved hormonal status of combat-sport athletes

    L-glutamine didn’t lower cortisol, but it kept testosterone from dropping during tough training, which made the testosterone-to-cortisol ratio better — just like the claim said.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.