Our methodology
How we evaluate supplements and turn the underlying research into a single rating.
What the score means
The overall score is designed to estimate how worthwhile a supplement is for the right user. It combines evidence quality, practical effect size, safety, dose clarity and cost-effectiveness. A high score does not mean everyone should take it; it means the supplement has a favorable evidence-to-risk profile for its intended use case.
Effectiveness score 0–100 combining evidence quality and benefit magnitude. Applied strictly. Popularity, marketing and anecdotes are ignored. When unsure between two bands, the lower one is picked.
- 90–100Excellent
Multiple meta-analyses confirm large, reliable effects (e.g., creatine for strength, omega-3 for triglycerides).
- 75–89Strong
Strong RCT evidence with consistent moderate effects.
- 60–74Moderate
Moderate evidence; works reliably for specific subgroups or conditions.
- 40–59Emerging
Emerging or mixed evidence; small or inconsistent effects.
- 20–39Weak
Mostly mechanistic, animal or observational evidence.
- 0–19Negligible
Negligible evidence or evidence of ineffectiveness.
How evidence grades work
A: strong human evidence with consistent outcomes.
B: promising or good human evidence with some limitations.
C: mixed, limited or context-dependent evidence.
D: weak, preliminary, animal-based, mechanistic or anecdotal evidence.
How risk levels work
Safe: low risk for most healthy adults at standard doses.
Caution: relevant interaction, dose, side-effect or population concerns.
Unsafe: unfavorable risk profile or avoid without medical supervision.
How cost is estimated
Cost is estimated from typical monthly use at commonly effective doses. It is not a price guarantee and may vary by brand, country and formulation.
What sources are used
Our ratings prioritize human clinical trials, systematic reviews, meta-analyses, official supplement fact sheets, regulatory safety limits and established clinical references.
Limitations
Supplement effects vary by person, baseline deficiency, diet, dose, health status, medication use and product quality. Rankings are educational and should not replace professional medical advice.
Medical disclaimer
HowToSupplement is an educational tool, not medical advice. Supplements can interact with medications, health conditions and surgery. Always consult a qualified healthcare professional before using supplements to treat a condition, replace medication, or during pregnancy or breastfeeding.