Creatine

Creatine Monohydrate (Cr·H₂O) — Phosphocreatine Energy System

Creatine is the most-studied, most-validated sports supplement in history — and one of the cheapest. Synthesized naturally in the liver from glycine and arginine, it is stored predominantly in skeletal muscle as phosphocreatine (PCr): the fuel reservoir behind every explosive movement, from a sprint to a back squat. The International Society of Sports Nutrition designates it "the most effective ergogenic nutritional supplement for increasing high-intensity exercise capacity and lean body mass during training." More than 500 RCTs back this up. The story doesn't stop at the gym. A decade of accumulating research on brain creatine has produced compelling 2025–2026 data on cognitive performance, depression augmentation, and even a first-in-human Alzheimer's pilot trial that confirmed creatine crosses the blood-brain barrier in meaningful amounts. Meanwhile, decades of feared side effects — kidney damage, cancer, dehydration, hair loss — are being systematically addressed by controlled trials and expert reviews, with most concerns either quantified as minor or debunked entirely. Standard dosing: 3–5 g/day continuously, with or without a loading phase.