Evidence status: current·Last updated 12 Jun 2026 · v2.3·Revision history
The Evidence Library
Every intervention, graded
Each ingredient and procedure read against the human trial data and scored A–D under one published methodology. Search or filter by grade and category.
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Grades for hair treatments change. Know when they do. Get an alert when a grade moves, plus each new review. About 2 emails a month. No products, no sponsors.
Added 2 recent RCTs to the evidence base; grade reaffirmed after re-scoring.
03 Mar 2026
v2.2
Incorporated a pooled safety analysis; expanded the adverse-effects section.
18 Nov 2025
v2.1
Reworked the delivery & vehicle discussion; added comparison figure.
22 Jul 2025
v2.0
Full re-review against updated methodology; all sources re-verified.
04 Feb 2022
v1.0
First published.
Grade Alerts
Grades for hair treatments change. Know when they do. Get an alert when a grade moves, plus each new review. About 2 emails a month. No products, no sponsors.