Evidence grading
What counts as evidence
Different sources answer different questions. Sift keeps them separate and shows uncertainty instead of blending everything into one score.
Reviewed 31 July 2026
A · Reviewed guidance and strong synthesis
Current professional guidance, systematic reviews, and high-quality evidence synthesis are preferred for important safety and efficacy claims.
B · Consistent clinical or formulation evidence
Useful human studies, reputable clinical references, and well-supported formulation principles may establish a reasonable over-the-counter strategy while retaining limitations.
C · Limited or indirect evidence
Small, indirect, inconsistent, or mechanistic evidence can inform cautious options but must not be presented with high confidence.
Formula and offer evidence
- Brand or current packaging sources are preferred for complete ingredient verification.
- Merchant text is provisional and may not match the regional variant.
- Every displayed offer must name the merchant, exact variant, currency, retrieval time, and freshness state.