Supplements that actually work
Three supplements have strong evidence for muscle and performance: creatine monohydrate, whey protein, and caffeine. A handful more have modest evidence. The rest of the industry — test boosters, BCAAs, fat burners, mass gainers — is mostly selling nothing of value.
- Creatine monohydrate, 3–5 g/day: the cheapest and best-studied supplement available.
- Whey is convenient protein — not a special muscle builder.
- Caffeine improves training output, not growth directly.
- Beta-alanine, citrulline, omega-3 are useful at the edges.
- If you eat properly, you don't need much else.
The four with strong evidence
- Creatine monohydrate. 3–5 g a day, no loading phase needed. Builds muscle and strength, improves training performance, safe for healthy people. The strongest evidence of any legal supplement.
- Whey protein. A fast, convenient protein. Not magic. Useful if you struggle to hit daily targets with food alone.
- Caffeine. 3–6 mg per kg bodyweight, 30–60 min before training. Improves output. A strong coffee works.
- Vitamin D (if deficient). Get a blood test first. If low, supplementation matters for muscle, immunity and bone health.
The supplement truth table
| Supplement | Evidence | Verdict |
|---|---|---|
| Creatine monohydrate | Strong | The best-studied supplement in sports nutrition. Builds muscle and strength. Cheap. Safe. |
| Whey protein | Strong | Not magic — just convenient protein. Useful if you struggle to hit daily grams. |
| Caffeine | Strong | Improves training performance. 3–6 mg/kg, 30–60 min before training. |
| Vitamin D (if deficient) | Strong | If your blood levels are low, supplementation matters. Get tested first. |
| Beta-alanine | Moderate | Helps with sets in the 60–240 second range. Modest effect, takes weeks to load. |
| Citrulline malate | Moderate | Small improvement in volume work. The 'pump' feeling is real, the muscle effect is small. |
| Omega-3 (fish oil) | Moderate | General health benefits. Some evidence for joint health and muscle protein synthesis. |
| Casein protein | Moderate | Slower-digesting protein. Useful before bed if it fits your schedule. |
| ZMA | Weak | Only useful if you're deficient in zinc or magnesium — most people aren't. |
| Glutamine | Weak | Already produced by your body. No meaningful effect on muscle gain or recovery. |
| Test boosters (D-aspartic acid, tribulus, etc.) | None | No evidence of raising testosterone meaningfully. Save your money. |
| BCAAs | None | Useless if you already eat enough protein. The amino acids are already in your food. |
| Fat burners | None | Mostly caffeine and stimulants dressed up. Calories burned: rounding error. |
| Mass gainers | None | Sugar and cheap protein. Cheaper to add oats, milk and peanut butter to a normal shake. |
Why creatine is the exception
Creatine is the only supplement that meaningfully accelerates muscle gain in healthy lifters. It does it by increasing the amount of phosphocreatine in your muscle cells, which lets you do slightly more work each session. Over weeks and months, that small per-session advantage compounds into more muscle and strength than you'd otherwise have. Monohydrate is the only form worth buying.
A note on BCAAs
Branched-chain amino acids became popular because they're absorbed quickly and signal muscle protein synthesis. The catch: a complete protein source (whey, chicken, eggs) already contains them and everything else needed to build muscle. If your daily protein is adequate, BCAAs add nothing. They're sold to a market that doesn't need them.
The bottom line
Build the foundation first: training, sleep, daily protein, daily calories. Add creatine. Add whey or caffeine if they help your schedule or training. Stop there. Anything you save not buying the rest is better spent on food.
Common questions
- Do I need to load creatine?
- No. Loading (20 g/day for a week) saturates your muscles slightly faster, but 3–5 g/day reaches the same level in 2–4 weeks. Loading is optional and can cause minor GI discomfort.
- Is creatine safe long-term?
- Decades of research on creatine in healthy adults show no adverse effects on kidney or liver function. People with existing kidney disease should consult a doctor.
- Can I take creatine if I'm a woman?
- Yes. The benefits are the same. There is no evidence that creatine causes water retention beyond the small initial intracellular increase, and no evidence of negative effects specific to women.
Related reading
Sources
- International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation — Kreider RB, et al.. Journal of the International Society of Sports Nutrition (2017).
- Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? — Wolfe RR.. Journal of the International Society of Sports Nutrition (2017).
- Effects of beta-alanine supplementation on exercise performance: a meta-analysis — Hobson RM, Saunders B, et al.. Amino Acids (2012).