Methodology

How we rank vendors

Every vendor on AminoCatalog has a single composite score from 0 to 100 that drives ordering on the directory and on every peptide page's vendor table. Five signals, transparent weights, audited right here.

The five signals

1Bayesian rating. Average star rating, adjusted toward the site-wide mean for vendors with few reviews so that a single 5-star review does not outrank a vendor with many 4.5-star reviews.
2Review volume. Total count of approved reviews on a logarithmic curve. The first ten reviews matter more than the next ten.
3Recency. Recent reviews count more than old ones, with exponential decay. Half-life is configurable; the default is 180 days.
4Response rate. For reviews rated three stars or lower, did the vendor reply within two weeks? Vendors with no negative reviews score 100 here.
5Trust signals. Four binary checks worth 25 points each: verified business docs, paid subscription tier, account age past six months, and no open flags.

Current weights

Signal	Weight
Bayesian rating	0.50
Review volume	0.15
Recency	0.15
Response rate	0.10
Trust signals	0.10

The formula

composite_score = (
  bayesian_component * 0.50
  + volume_component   * 0.15
  + recency_component  * 0.15
  + response_component * 0.10
  + trust_component    * 0.10
) × tier_multiplier

Each component is normalized to a 0–100 range before weighting. Tier multipliers are free × 1.00, verified × 1.05, featured × 1.10. The final score is capped at 100.

Tie-breaking

When two vendors score within 1 point, we break ties by review count first, then by account age.

Conflict of interest

Featured placements are clearly labeled. The tier multiplier is a small lift, not a domination effect — a featured vendor with weak reviews still loses to a free vendor with strong reviews.