How recommendations are made
Our evidence & sources
We use verified product information, published haircare research and transparent matching rules. These three things provide different kinds of evidence. They should not be confused.
Evidence-page audit: 3 November 2026.
How we decide which products to show
- Product identity and formulation. We record the exact product, ingredient declaration, available UK-formulation evidence and its source. Conflicting or incomplete ingredients may mean a product is held for review.
- Category and ingredient features. We record researched features such as cleansing profile, conditioning polymers, silicones, hydrolysed protein, film-forming ingredients and the manufacturer's stated intended use.
- Your answers. The matchers apply documented eligibility, preference and ranking rules to the eligible products. We explain the reasons for individual recommendations.
- Presentation. Retailer links, prices, brand recognition and affiliate arrangements must not override product-fit rules. Price and stock information are snapshots, not live guarantees.
Our research master spreadsheet records product and formula evidence in fields such as Product URL(s), Ingredients Verbatim, UK Formulation Verified, Verification Status and Conflict Notes. Product-result pages also provide source links where recorded.
How different hair concerns affect recommendations
These are simplified explanations of our current rules. They are evidence-informed heuristics (structured, reasoned estimates), not clinical predictions or independently calibrated effectiveness scores.
| Your concern | What our rules consider | Important limitation |
|---|---|---|
| Hair feels dry or shampoo feels stripping | May favour a gentler-leaning cleansing profile and conditioning ingredients for routine washing; buildup-cleansing needs are handled separately. | “Sulfate-free” does not automatically mean gentle; a full formulation matters. |
| Tangling or hard-to-comb hair | May favour conditioners with cationic conditioning agents, conditioning polymers or silicones. | An ingredient list cannot tell us exactly how much slip a finished product provides. |
| Breakage or hair with heat/chemical damage | May favour temporary conditioning and hydrolysed-protein signals, depending on the category and your answers. | Cosmetics cannot permanently rebuild all damaged hair; protein presence does not prove repair. |
| Heavy products leave hair coated or flat | May lower priority for certain richer, coating ingredients when you report this preference. | Ingredient presence alone does not measure how heavy a finished product will feel. |
| Buildup after styling | May prioritise verified clarifying or stronger-cleansing shampoos over a very conditioning co-wash. | Cleansing profile is a research classification, not a standardised laboratory cleaning test. |
| Pre-wash hair-oil protection | May give coconut-dominant oils extra priority where the use matches the goal. | Research on coconut oil does not demonstrate that every coconut-containing product performs the same way. |
| Styling hold or curl definition | Uses detected film-formers and verified intended-use wording (e.g. curl-defining or strong-hold). | Marketing claims and ingredient flags are not independently measured hold scores. |
| 4A, 4B, 4C or high/low porosity | These labels alone do not add automatic product-ranking points. | There is insufficient validated product-outcome evidence for simple “4C must use X” or “low porosity must avoid Y” rules. |
Where point values come from: the internal priority weights (such as +1, +2 or +3) were chosen as decision rules; they are not effect sizes measured in scientific trials. They need further independent review and outcome validation.
Scientific sources already recorded during development
The following references were present in our Hair Profile Rules documentation before this source-page audit. Their presence does not mean each individual scoring rule was independently supported by these papers.
- American Academy of Dermatology. 6 curly hair care tips from dermatologists ↗. Context on curly/coily hair, dryness, tangling and care.
- American Academy of Dermatology. Tips for healthy hair ↗. General hairwashing and conditioning guidance.
- Humphrey, J. G., Harding, M. J., Cartwright, K. M., Thomas, L. E. & Luke, J. (2026). Afro-textured hair care: a narrative review and recommendations for dermatologists ↗. International Journal of Women's Dermatology. A narrative review of Afro-textured hair properties and care; not a product-comparison trial.
- Classification of High Curl Pattern Hair: A Systematic Review and Clinical Perspective (2026). Read the systematic review abstract ↗. Background on curl-pattern classification, not evidence for a specific product score.
Scalp-safety references already in the project
These NHS pages inform when we recommend seeking professional advice rather than treating a cosmetic haircare product as a medical remedy:
Additional scientific reading identified during this audit
Transparency note: These are relevant references reviewed on 3 November 2026 to assess the existing ingredient-based rationale. They were not previously cited in the recommendation rulebook, and we are not claiming that they were the original basis for the current numerical weights.
- Dias, M. F. R. G. (2015). Hair cosmetics: an overview ↗. International Journal of Trichology, 7(1), 2–15. Reviews surfactants, conditioner ingredients, silicones and protein hydrolysates.
- Dias, M. F. R. G., Loures, A. F. & Ekelem, C. (2021). Hair Cosmetics for the Hair Loss Patient ↗. Indian Journal of Plastic Surgery, 54(4), 507–513. Reviews the cosmetic role of conditioners, smoothing agents and hydrolysed proteins.
- Carvalho, R. M., Melo, D. F., Kelati, A. & Tosti, A. (2025). With or without Silicones? A Comprehensive Review of Their Role in Hair Care ↗. Reviews conditioning, shine, lubrication and buildup limitations; not a test of every finished product.
- Rele, A. S. & Mohile, R. B. (2003). Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage ↗. Journal of Cosmetic Science, 54(2), 175–192. Compares oil treatments for hair-fibre protein loss; does not validate all coconut-oil blends.
Shampoo rules: first scientific review
Review updated 3 November 2026: We compared our shampoo-classification and ranking rules with cosmetic-chemistry and dermatology literature. The sources support analysing the complete cleansing formulation, recognising the role of conditioning polymers and distinguishing ordinary washing from buildup removal.
However, they do not validate our exact ranking points or establish a clinically proven best shampoo. A shampoo being sulfate-free is not, by itself, proof that it is gentle; a conditioning polymer appearing in an ingredients list does not guarantee the same benefit in every finished product. Our categories are evidence-informed estimates, not measured laboratory cleansing-strength grades.
Key reviewed source: Thompson et al. (2023), Shampoo Science: A Review of the Physiochemical Processes behind the Function of a Shampoo ↗. The journal also published a correction to its chemical-structure table ↗. The original review includes authors affiliated with Unilever R&D; this is a relevant disclosure when appraising the paper.
Our first scoring checks found numerous equally ranked shampoos. We therefore treat the results as leading candidates under the current rules, not guaranteed individual outcomes. More independent validation is needed.
What we cannot claim yet
- Our recommendations are not clinical diagnoses, treatment advice or laboratory-tested performance rankings.
- We have not run controlled head-to-head trials of the listed products, and we do not have enough user-outcome data to calibrate the numerical ranking weights.
- Ingredient presence does not reveal ingredient concentration or prove how a full formula performs on an individual person's hair.
- Manufacturer wording describes intended use and may be marketing; it is not independent proof of effectiveness.
- Research sources and ingredients may change when products are reformulated. Where UK versions conflict, the correct approach is manual review rather than guessing.
- Rule-to-article traceability is incomplete. The rulebook identifies rules and evidence categories but does not yet attach an individual published study to every scientific heuristic. That remains an active research task.
Our intended transparency standard is: Your answer → Matching rule → Product feature → Formula evidence → Recorded product source, with applicable scientific literature attached to the rule as it is audited.