Our Review Methodology

Every supplement on RankOfSupplements is evaluated using the same transparent, evidence-based scoring system. No product can pay for a higher ranking. Here is exactly how we score each product.

Scoring Criteria

Ingredient Quality

35%

We evaluate every active ingredient against peer-reviewed research. We check for clinically studied forms (e.g., KSM-66 ashwagandha vs generic extract), bioavailability enhancers, and avoid products relying on filler ingredients.

Dosage Adequacy

25%

Each ingredient's dose is compared to amounts used in clinical trials that demonstrated efficacy. Products using proprietary blends that hide individual dosages are penalized. We calculate what percentage of the clinical dose each ingredient provides.

Third-Party Testing

20%

We verify certifications from NSF International, USP, Informed Sport, ConsumerLab, or equivalent organizations. Third-party testing confirms that the product contains what the label claims and is free from contaminants.

Value for Money

10%

We calculate the true cost per effective serving, accounting for dosage splits and subscription discounts. A high-quality product at a fair price scores better than a mediocre product at a low price.

User Experience

10%

Practical factors including taste, mixability, capsule size, ease of use, packaging quality, and customer service responsiveness. These factors affect compliance and long-term satisfaction.

How Scores Are Calculated

Each product receives a score from 0 to 10 in each of the five criteria above. The overall score is a weighted average:

Overall = (Ingredient x 0.35) + (Dosage x 0.25) + (Testing x 0.20) + (Value x 0.10) + (UX x 0.10)

Independence & Conflict of Interest

  • We do earn affiliate commissions when you purchase through our links.
  • Commission rates never influence product scores or rankings.
  • Products are scored before affiliate links are added.
  • We regularly feature products where we have no affiliate relationship if they score well.
  • Our scoring methodology is applied consistently across all products.

Frequently Asked Questions

How do you score supplements?
Each product is scored 0-10 across five weighted criteria: Ingredient Quality (35%), Dosage Adequacy (25%), Third-Party Testing (20%), Value for Money (10%), and User Experience (10%). The overall score is a weighted average of those five sub-scores.
Do brands pay you to be ranked higher?
No. Product scores are calculated from the published rubric before any affiliate links are added, and commission rates have no input into the formula. We regularly feature top-scoring products where we have no affiliate relationship.
What counts as third-party testing?
We accept certifications from NSF International, USP (United States Pharmacopeia), Informed Sport, ConsumerLab, or equivalent independent labs. Self-funded "in-house testing" does not count.
Why is dosage weighted so heavily?
Because it is the single biggest source of supplement waste. Many products contain the right ingredient at a fraction of the dose used in the clinical trial that demonstrated efficacy. Our dosage score directly compares each ingredient's amount to the clinically studied dose, penalising under-dosed products and proprietary blends.
How often are scores updated?
We re-score a product whenever its formulation, dosage, third-party testing status, or price meaningfully changes. Pages display a "Last Updated" badge so you can see how fresh the analysis is.