How PurScore Rates Products
This page documents how our ratings are created — what data we use, how we weight it, and what our ratings do not cover.
The three scores in detail
1. Naturalness score (0-100)
Measures the proportion of natural ingredients in a formula, weighted by position in the INCI list (an earlier position means a higher concentration).
- Positive (+): plant oils, water (Aqua), plant extracts, minerals.
- Negative (−): silicones (Dimethicone), PEGs, synthetic polymers, microplastics.
- Source: EU CosIng + Open Beauty Facts.
2. Safety score (0-100)
Assesses the regulatory and allergenic risk classification of ingredients.
- Questionable (lowers the score): substances on the EU watch list, allergenic preservatives (MIT/CMIT), endocrine-disrupting substances.
- Banned (score 0): substances listed in Annex II of the EU Cosmetics Regulation (1223/2009).
3. Share of natural ingredients (0-100)
Percentage of ingredients classified as natural across the whole formula, without weighting by position. It complements the naturalness score, which looks mainly at the top of the INCI list.
Overall score (0-100)
Weighted average: 50% safety, 30% naturalness, 20% share of natural ingredients. Formulas with several active ingredients get a bonus: +5 points from two, another +3 from four actives (max. 100).
Price does not affect the overall score. Where prices are known, a value-for-money figure is shown separately.
If we know fewer than 5 ingredients of a product, the overall score is capped at 60 points; with fewer than 3 ingredients at 45 points.
Date sources
| Source | Content | Licence |
|---|---|---|
| EU CosIng | Ingredient data, regulatory status | Public Sector Information (EU) |
| Open Beauty Facts | Cosmetics data, INCI lists, photos | ODbL |
| Open Food Facts | Food data, Nutri-Score, NOVA | ODbL |
Update cycles
- Product data: weekly.
- Ingredient database: monthly (EU CosIng).
- Prices: daily (where a store interface is available).
When our Score may be less accurate
Our algorithm is optimised for cosmetics applied to the skin (creams, serums, lotions, emulsions, make-up). For this category, the rating is the most reliable.
Rinse-off products (toothpastes, shampoos, shower gels) are rated only as a rough guide — their safety depends largely on the contact time with the skin, which the algorithm does not measure. For these products, treat the Score as a hint rather than the final word.
Food products (supplements, functional foods) are rated using a different logic (Nutri-Score + NOVA) — differences from the cosmetics Score are to be expected.
Always read the full ingredient list and consult a doctor or pharmacist if you have any concerns.
How we read INCI
The INCI list (International Nomenclature of Cosmetic Ingredients) lists ingredients from the highest concentration to the lowest. Ingredients in positions 1-5 account for around 80% of the formula — they have the greatest impact on the rating. Allergens are always flagged regardless of their position.
What does NOT affect the Score
Our algorithm rates ingredients only. We do not take into account: fragrance, brand, the price of the packaging, design, advertising, or certifications (organic, eco). That is why a product from an expensive brand may have a lower Score than a cheap one from the drugstore.
What PurScore is NOT
- ❌ It is not medical advice.
- ❌ It is not a laboratory test.
- ❌ It is not an individual recommendation.
- ❌ It does not guarantee completeness of the data.
Frequently asked questions
Are PurScore ratings medically binding?
No. PurScore is an information service and does not replace medical advice.
How often is the data updated?
Product data weekly, the ingredient database monthly, prices daily.
Can manufacturers influence their own rating?
No. The rating is calculated automatically. There are no paid placements or manipulation.
Why does an organic product sometimes get a lower rating?
The rating concerns the ingredients, not the certification. Natural ingredients can also be allergenic.
Got feedback?
Spotted an error in a rating? Missing an ingredient in the database? Write to us — we review every report by hand.
Disclaimer: Information provided without warranty. PurScore is not medical advice.
Methodology version 1.0 · 2026-04-15