Which Supplements Actually Work? Levels of Scientific Evidence
Sports supplements are a multibillion-dollar industry. Very few supplements have grade "A" evidence. Learn to tell the real from the fake.
The Supplement Hierarchy
The Australian Institute of Sport (AIS) classifies supplements from A to D according to the strength of the evidence. Most products on store shelves fall into categories C–D.
Evidence Level A (Works)
Creatine Monohydrate
Effect: Gains in power and volume during repeated high-intensity exercise
Dose: 3–5 g/day; no loading phase needed
Note: Cheap products are just as effective as expensive ones.
Caffeine
Effect: Endurance, power output, reaction time
Dose: 3–6 mg/kg, 45–60 min before exercise
Beta-Alanine
Effect: Acid buffering during high-intensity efforts lasting 1–4 minutes
Dose: 3.2–6.4 g/day (in divided doses)
Nitrate / Beetroot Juice
Effect: A 1–3% performance gain in endurance sports
Dose: ~500 ml of concentrated beetroot juice, 2–3 hours before
Evidence Level B (Limited Evidence)
- Protein powder: It works, but it has the same effect as real food. It is a convenience product.
- BCAAs: Provide no extra benefit if you are getting enough protein.
Evidence Level C–D (Unsupported or Risky)
- Supplements that "guarantee" fat burning
- Testosterone "boosters" (fenugreek, tribulus)
- Glutamine (insufficient evidence of immune support for healthy athletes)
Safety
National-team athletes should choose products carrying NSF Certified for Sport or Informed-Sport certification.
This article is general information. Talk to a paediatrician or dietitian before deciding on a nutrition plan or supplements for your child.