Sports Supplements Guide: Which Actually Work and Which Don't (2026)

Do supplements really work?

The supplement industry generates billions of dollars annually, but only a handful of products have solid scientific evidence. This guide separates facts from marketing, based on peer-reviewed research.

Tier 1: Strong evidence

Creatine Monohydrate

The most studied supplement in sports science. Increases phosphocreatine stores in muscles, improving performance in high-intensity, short-duration efforts (sprinting, weightlifting). Proven benefits: +5–15% strength, better muscle recovery, may benefit cognitive function. Dose: 3–5g/day. No loading phase necessary.

Whey Protein

Convenient way to hit protein targets. Not magic — it's just protein. Advantages: fast absorption post-workout, complete amino acid profile, high leucine content (triggers muscle protein synthesis). Dose: use to supplement diet, not replace it.

Caffeine

The most consumed ergogenic substance in the world. Proven to improve endurance, strength, and focus. Dose: 3–6mg/kg body weight (200–400mg for most people) 30–60 minutes before training. Tolerance builds quickly — cycle usage.

Tier 2: Moderate evidence

Beta-Alanine

Increases carnosine in muscles, delaying fatigue in efforts of 1–4 minutes. Useful for HIIT and combat sports. The tingling sensation (paresthesia) is harmless. Dose: 3.2–6.4g/day, preferably split into smaller doses.

Citrulline Malate

Improves blood flow and reduces muscle soreness. May increase training volume. Dose: 6–8g taken 60 minutes before training.

Tier 3: Limited or no evidence

• BCAAs: Redundant if you already eat adequate protein. Save your money.
• Glutamine: Not necessary for people eating enough protein. Does not accelerate recovery in healthy athletes.
• Fat burners: The only active ingredient that works is caffeine. The rest is marketing.
• Testosterone boosters: No supplement legally available significantly raises testosterone levels.

Safety and quality

• Look for products certified by NSF, Informed Sport, or USP — third-party tested for banned substances.
• Supplements are not FDA-regulated with the same rigor as medications — buyer beware.
• If you're an athlete subject to anti-doping testing, only use certified products.