← The FormularyMuscle & performanceL-glutamine
The work after the work. One ingredient, one job.
The honest version most brands won't give you: glutamine is wildly popular and the evidence for the muscle claims is thin. It's the most abundant amino acid in the body, your gut and immune system burn through a lot of it, and under real physical stress demand can outrun supply — that's the legitimate case. As a mass-builder for a well-fed lifter, temper your expectations.
The most abundant amino acid in the body, popular around training and gut health.
Glutamine fuels the fast-dividing cells of your gut lining and immune system, and it's a building block your body leans on during hard training, illness or dieting. Supplementing tops up a pool that intense stress can deplete — which is why the better-supported angle is recovery and digestive integrity, not biceps.
Used as part of a post-training recovery routine and for digestive-lining support.
Men under heavy training load, in a deep cut, or dealing with gut sensitivity around dieting. If you're a well-fed lifter expecting dramatic gains, this isn't your hero — REPAIR is deliberately one honest ingredient doing one modest job.
One scoop (around 3–5 g) daily, in water or your shake. Unflavoured, so it disappears into anything; timing is unfussy.
Subtle at best, and mostly on the recovery-and-gut side rather than anything you'll see in the mirror. Supporting cast — judge it by how your stomach and recovery feel across a hard block, not by scale weight.
Grade C — genuinely mixed. Reasonable support for gut and immune roles under stress; weak support for muscle-growth claims in healthy, well-fed adults. We'd rather say that than inflate it.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.