Ingredient Rating Criteria
This page explains how CleanFormulation scores and classifies soap and cleanser ingredients. Technical evidence is translated into contextual interpretive flags: Generally Tolerated, Use with Caution, and Watch / Under Review: using consistent, transparent criteria.
Why an explicit rating criterion?
Ingredient labels are dense and often ambiguous, and many readers cannot translate an INCI list into meaningful risk context. We created a structured criteria system so classifications are reproducible, explainable, and open to scrutiny.
The goal is not to issue legal, medical, or regulatory judgments, but to provide evidence-based explanatory context that helps readers understand ingredient information and frame informed discussions with relevant professionals.
At-a-glance: the five core rating dimensions
- Evidence Strength (40%) – quality, consistency, and relevance of scientific literature and regulatory assessments.
- Documented Contact & Allergen History (20%) – reported human contact reactions and surveillance data.
- Exposure & Concentration Context (15%) – typical use concentrations and rinse-off vs leave-on exposure patterns.
- Formulation Context (15%) – interaction with other formulation components affecting exposure behavior.
- Environmental & Persistence Signals (10%) – ecological persistence and regulatory environmental context.
Weights are published alongside technical worksheets to support reproducibility.
Evidence strength and tiering
| Tier | Sources | Role |
|---|---|---|
| A | Regulatory opinions, systematic reviews | Primary interpretive foundation |
| B | Peer-reviewed human exposure studies | Strong contextual support |
| C | Animal toxicology, in-vitro studies | Mechanistic insight |
| D | Preprints, supplier data | Supplementary only |
Exposure and formulation context
Ingredient behavior varies with concentration, formulation, and exposure pattern. Scores are adjusted based on rinse-off versus leave-on use, typical concentration ranges, and formulation structure.
Where concentration data are unavailable, conservative assumptions are used and explicitly stated on ingredient pages.
Environmental context
Environmental considerations do not determine individual skin interaction but provide important contextual information. Where relevant, environmental persistence or regulatory signals are noted alongside dermal context.
Composite score interpretation
| Score Range | Flag | Interpretive meaning |
|---|---|---|
| > 70 | Generally Tolerated | No common risk signals identified in typical use contexts; individual sensitivity may still vary. |
| 40–70 | Use with Caution | Heightened context sensitivity or evidence uncertainty depending on formulation and use. |
| < 40 | Watch / Under Review | Evidence is limited, conflicting, or evolving; interpretation should remain cautious. |
Limitations
- Incomplete ingredient concentration disclosure.
- Variability across study designs and populations.
- Rare individual reactions that no classification system can predict.
Classifications describe evidence context and do not replace professional medical or regulatory evaluation.
Transparency and reproducibility
- Primary source lists with DOIs or regulator links.
- Published changelogs for substantive updates.
- Archived scoring worksheets available to qualified reviewers.
How classifications are intended to be interpreted
- Readers: Use flags as a high-level summary when interpreting ingredient information.
- Researchers: Request reproducibility materials for independent analysis.
- Formulators: Reference evidence context when reviewing published literature.
These criteria are intentionally explicit so interpretations can be understood, replicated, and challenged: the basis of research trust.