What Works Skin — Independent · Evidence-First · Ad-FreeIssue 014 · 20 April 2026 · Next: 04 Maywhatworksskin.com
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Transparency · Grading rubric

Last updatedRubric v1.2

How we rate.

The same four-tier rubric — A through D — applies to ingredients, products, and supplements alike. The criteria differ slightly by category, but the badge stays the same so you can read it at a glance across the site. The full dossier (principles, conflicts of interest, review cadence, corrections, funding) lives on the methodology page.

The four-tier rubric.

Tier
Evidence threshold
Consensus
What we say
Tier A
≥ 2 RCTs, n > 50, vehicle-controlled, replicated end-points
International guideline body lists as standard of care
Recommended without qualification
Tier B
1 RCT or strong observational data; mechanism well-established
Mainstream practitioner adoption
Recommended for the right person, with caveats
Tier C
Mixed or modest data; small studies; preliminary signals
Some practitioner support, no consensus
Optional; try if low-cost and low-risk
Tier D
No human evidence, contradicted by trials, or marketing-only claims
Marketing exceeds science
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Adjustments for products.

A product Tier reflects the formulation as a whole — not just the active. We assess: in-spec dose of the active, vehicle quality (penetration / stability), realistic price-per-use, and complete ingredient list (we down-grade for known sensitisers in unnecessary positions).

  • Active concentration verified
  • Vehicle pH where relevant
  • Compatibility with claimed routine
  • No known issue ingredients without reason

Adjustments for supplements.

Supplement tiers weight bioavailability, third-party testing, and human (not in-vitro) outcomes more heavily. Anything Rx-only carries a parallel safety review by Dr. Sundeep before publication.

  • Human RCTs, not in-vitro
  • Standardised extract documented
  • Realistic real-world dose
  • Drug-interaction and pregnancy review

Read the full dossier

The principles that predate the rubric, our conflicts-of-interest declaration, the weekly/monthly/quarterly/annual review cadence, the corrections policy, and the source of every rupee that funds the publication — all live in the methodology dossier.

Read the methodology dossier →