How we evaluate
Product Evaluation Methodology
This page explains exactly how Collagen Science chooses and ranks the collagen products on our comparison page. Our goal is to be transparent: you should be able to see why a product is included and how it scored.
How products become eligible
We start from the products that are currently selling well in the most relevant Amazon category (or the closest category). Amazon popularity decides only eligibility — which products we review. It does not contribute to the quality score below, because being a best seller is not evidence of quality or effectiveness. We remove near-identical size variations of the same product, and we avoid blends that obscure the amount of the primary ingredient.
How we score
Each eligible product is scored on the following criteria. The weights sum to 100%.
We do not score value (price or cost per serving), because we do not publish a verified current price for these products. The weight that value would have carried has been redistributed proportionally across the criteria below, and no product receives a “best value” badge.
Uses a well-studied, bioavailable form of the ingredient as its primary active.
Labeled serving matches amounts used in the published human research.
Per-serving amounts are stated clearly, with no proprietary blends hiding quantities.
Independent certification by a named organization is weighted above an unverified brand claim.
Fewer unnecessary fillers, binders, and additives.
Format and ease of taking the labeled serving.
Collagen-specific adjustments
Hydrolyzed collagen peptides with a clearly labeled gram dose are compared; non-peptide or topical formats are out of scope.
Scores, rounding, and ties
Each product’s score is the weighted average of the sub-scores above, on a 0–10 scale. The score we display is rounded to one decimal place; the ranking itself uses the exact, unrounded weighted score.
When two products have the same exact score, we break the tie in this fixed order:
- higher exact (unrounded) weighted score;
- higher third-party testing & certification sub-score;
- higher label-transparency sub-score;
- higher ingredient-form & formula sub-score;
- higher labeled-dose sub-score.
We never break ties using price, value, star rating, review count, Best Sellers Rank, brand recognition, or the order products happen to appear in our files. If two or more products are still exactly tied after every step above, we present them as a tie and do not crown a single “Best Overall” — any of the tied products is an equally-ranked top pick.
Testing confidence tiers
We never treat these three tiers as equivalent:
- Independently certified
- A named third-party organization (for example NSF Certified for Sport, Informed Sport/Choice, or USP) independently certifies the product. This is the highest confidence tier.
- Brand states third-party tested
- The brand publicly states the product is third-party tested, but we have not independently verified a certification. We report the claim as a brand statement.
- Testing not independently verified
- We could not confirm an independent third-party certification for the listing. This is not a negative judgment — only the absence of verified information.
What we do not display
We do not show live prices, star ratings, review counts, stock availability, or Best Sellers Rank on our pages. These change constantly, and we do not yet run a process to keep them current, so publishing a fixed value would be misleading. Check the product’s Amazon page for the current price, availability, and rating. Internal popularity observations only inform which products we review; we never present them as a permanent ranking claim.