Nécessaire · The Shampoo | Hyaluronic Acid
Three independent Greenlens lenses read the same 18 ingredients and land 40 points apart. That gap is not an error. Each lens asks a different question, and this page shows every answer, ingredient by ingredient, blended into nothing.
Our sources have reference data on all 18 listed ingredients. Our sources can only speak to ingredients they recognize — either flagged by an authority or known to be a common, well-characterized ingredient. An uncharacterized ingredient is a gap in our data, not a clean bill of health: a quiet safety scan over ingredients we can’t place is a weaker signal than one over ingredients we can.
Independent
The regulatory baseline. Follows EU cosmetic law: prohibited and restricted ingredients cost points, and allergen labelling is capped so it cannot tank a score on its own.
No EU-regulated hazards recognized among 18 ingredients.
Independent
The strict lens. Flags any ingredient with a listed hazard trait (SIN List, IARC, Prop 65), even when regulators still permit it.
Flagged 1 of 18 ingredients on hazard grounds: 1 strong sensitizer. Score capped: a strong sensitizer is present.
Independent
The lenient lens. Trusts dose and regulation: permitted ingredients kept within their legal caps are tolerated, and only genuinely prohibited substances take a big hit.
No prohibited or high-risk ingredients among 18; permitted ingredients tolerated.
These lenses disagree. A split of 40 points crosses our disagreement threshold (20). We keep every verdict and never average them; the table below is where the split comes from.
| Ingredient | Scan | Precautionary | Tolerance |
|---|---|---|---|
| Cocamidopropyl BetaineChemSec SIN List (Substitute It Now) | · | −12sensitizer | · |
−N points subtracted by that lens, labelled with its concern · noted, 0 seen but tolerated under that philosophy · · not on that lens's reference lists. Open an ingredient for the full reasoning and every rater's position. 17 other ingredients matched no list at all.
Coverage & match quality
2 ratings · 1 of 4 axes
The overall ring on the product page is the weighted mean of the four pillars using your weights, computed fresh on every visit and never stored. How each lens's reference lists were built, penalty by penalty, is on the methodology page.
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