How we built this chart
Methodology and sources
Every pattern description, care recommendation, and product pick on this site traces to a named primary source. This page lists them.
Sources reviewed May 2026
Primary sources
The literature behind the 1A-4C system and the care recommendations layered on top is a mix of Walker's own classification, peer-reviewed cosmetic-science and trichology research, the American Academy of Dermatology's consumer haircare guidance, and the long-form Type 4 documentation done by Black creators and the NaturallyCurly community. We cite all of it by name.
| Source | Refresh | What we use it for |
|---|---|---|
| Andre Walker, Andre Talks Hair! (1997, Simon & Schuster) | Reference (out of print but widely available) | Primary source for the 1A-4C framing. We cite Walker's own writing for the system rather than secondary summaries. |
| L'Oreal Research and Innovation, hair-science.com | When updated | Cuticle, cortex, medulla structure; melanin biology (eumelanin and pheomelanin); ethnic-hair morphology and curl-shape origin. Used for the pattern descriptions that explain why each type behaves the way it does. |
| American Academy of Dermatology, aad.org (hair care topic pages) | When AAD revises | Cleansing frequency, breakage triage, traction alopecia warning thresholds, heat-styling guidance. Our care-routine recommendations cross-check against AAD's consumer guidance. |
| Journal of Cosmetic Science (Society of Cosmetic Chemists) | Continuous (peer-reviewed) | Hair-fibre structure, cuticle scale lift, conditioner deposition mechanisms, ethnic-hair structural variation studies. Used to ground the porosity and product-mechanism claims. |
| International Journal of Trichology (PMC) | Continuous (peer-reviewed) | Clinical context on hair-fibre morphology, alopecia categorisation, scalp microbiome, trichoscopy research. Used for the medical-adjacent claims about when a hair issue is a dermatologist concern rather than a styling concern. |
| NaturallyCurly.com curl-pattern community archive | Continuous (community-driven) | Per-type long-form community documentation, especially for Type 3-4 textures. Used as cross-check on real-world product behaviour, common mistakes, and texture-specific routines. |
| Whitney White (Naptural85), YouTube long-form Type 4 series | Continuous | Documented Type 4 care over a decade; primary source for 4A and 4B routine specifics. Named and linked rather than paraphrased. |
| Procter & Gamble Hair Care Research | Industry reference | Industry hair-fibre research context, surfactant chemistry, conditioner-active mechanism. Used as cross-reference on product-category framing. |
| Unilever Beauty and Wellbeing research | Industry reference | Cross-reference industry context on hair-fibre research and product-development framing. |
| Mintel hair care market reports (public summaries) | Quarterly to annual | Category framing on product spend by texture, brand market share, retail-channel mix. Used for the editorial honesty about commercial bias toward Type 3 over Type 4 product investment. |
| Sally Beauty, Ulta, Sephora retail availability | Continuous | Cross-check that recommended products are actually available at the price points readers shop. Where a recommended product is online-direct-only, we say so on the product card. |
In scope
- The Andre Walker 1A through 4C curl pattern classification, all 12 patterns covered at equal depth on a per-type sub-page.
- Porosity as an independent second axis, with the float test protocol and the low / medium / high care implications.
- Density and strand thickness as supporting axes that influence per-type product choice.
- Care routines per type: cleansing frequency, conditioning protocol, leave-in and styling layer logic (LOC versus LCO method), night routine, common mistakes.
- Real-product recommendations per type from category leaders at the price points readers shop (SheaMoisture, Pattern Beauty, DevaCurl, Ouidad, Mielle Organics, Cantu, Carol's Daughter, with brand and product-category reasoning).
- The texturism debate around the Walker system: what it is, the criticism from Black hair scholars and creators, and what a responsible reference site owes its readers.
- An interactive 8-question quiz that returns a primary type, a secondary type if the reader is between two, and a confidence score.
Out of scope
- Clinical diagnosis of hair-loss conditions, scalp disease, or alopecia categories. Trichoscopy, biopsy, and treatment decisions belong with a dermatologist or licensed trichologist.
- Prescription decisions for finasteride, minoxidil, spironolactone, or any other hair-related medication.
- Trichologist consultations and personalised care plans.
- Race-essentialist claims about which textures are inherent to which heritage. The Walker system is descriptive of pattern, not predictive of heritage; we say so.
- Treatment of the Walker system as a definitive scientific taxonomy. It is a styling-practical shorthand with documented limits, and the texturism debate page is the honest record of those limits.
- Diagnostic claims for hormonal hair changes (postpartum shedding, menopausal thinning, thyroid-related texture shifts). General context appears in the FAQ; diagnosis is a clinician's role.
Calculation framework
Shrinkage percentage
Reported per type as a range, not a point estimate. Methodology: measure stretched length root-to-tip when wet under no tension, then measure natural dry length at the same point with no manipulation. Ratio reported as percentage. Walker's original system gave directional shrinkage notes; the precise ranges (e.g. 4A 50-65%, 4C 75%+) draw on NaturallyCurly community-aggregated data plus Type 4 creator documentation.
Porosity float test
Single clean hair strand (naturally shed, not pulled) placed on the surface of a glass of room-temperature water; observe at 3-4 minutes. Floats = low porosity. Sinks to middle = medium porosity. Sinks to bottom = high porosity. Limitation: float test is directional, not definitive. Lab Muffin Beauty Science has documented its limits; we surface that on /porosity and recommend the slip test as a cross-check.
Curl diameter measurement
Per-type benchmark: 3A loose curl roughly the diameter of a thick chalk or large marker; 3B closer to a standard marker; 3C close to a pencil; 4A close to a crochet needle; 4B-4C Z-pattern rather than spiral so diameter benchmarks do not apply. Self-test: wrap a natural curl around the named object and observe fit.
Strand thickness benchmark
Compare a single strand to standard sewing thread. Thinner than thread = very fine (1A territory, often 4C in the strand though densely packed); same as thread = medium; thicker than thread = coarse (1C, 2C territory). Used in the quiz weighting and on per-type pages.
Quiz weighting algorithm
Eight questions (wet pattern, dry pattern, shrinkage, strand pattern, porosity, density, strand thickness, styling behaviour) each contribute weighted points to up to three candidate types. Primary type = highest score. Secondary type returned if within 25% of primary score. Confidence score scales with the gap between primary and secondary. Source: src/app/quiz/page.tsx is the canonical algorithm; the README in src/lib/hairTypes.ts holds the data spine.
Refresh cadence
Sources reviewed monthly. Single LAST_VERIFIED_DATE constant in src/lib/schema.ts drives every freshness indicator on the site: footer stamp, hero badges, WebSite schema dateModified, every Article schema dateModified, and the Reviewed against primary sources badge on this page and /about. Rolling one constant forward updates the entire site by construction.
Out-of-cycle refresh triggers:
- AAD revises its consumer hair-care topic pages (cleansing frequency, traction alopecia thresholds, breakage triage).
- A peer-reviewed paper in the Journal of Cosmetic Science or International Journal of Trichology materially changes a per-type recommendation.
- A category-leader product (Pattern Beauty, SheaMoisture, DevaCurl, Mielle Organics) reformulates or discontinues a recommended SKU.
- A flagged reader correction with a primary-source citation.
- A new long-form Type 4 documentation series from a credited creator (Whitney White, Curly Nikki, OurX) that changes the recommended routine for 4A, 4B, or 4C.
Limitations
- The Andre Walker system implies a single type when most people have two or more textures across the head. The quiz returns a primary and secondary type to reflect that; the per-type pages explicitly call out the most-confused boundaries (2C / 3A, 3C / 4A, 4B / 4C).
- Photo placeholders use coloured CSS blocks today with documented alt text. Photography from diverse libraries (Nappy.co, Create Her Stock) and commissioned shots are the next phase. The placeholder approach is honest; it is also a real ranking gap against competitors with photo grids.
- Commercial bias in the product market: Type 3-4 product investment dominates over Type 1-2 product investment by category. Our Type 1-2 recommendations are leaner partly because the category is leaner, not because the typing matters less.
- Mixed-texture reality is poorly captured by any single-type label. We treat primary type plus secondary type plus porosity plus density as the meaningful product-decision input set, rather than treating one Walker letter as the answer.
- Hormonal, age, and chemical-treatment drift can shift pattern over time. The FAQ covers this; the typing on this site is a snapshot, not a permanent assignment.
Corrections
Correction or factual challenge? Email via the contact form at digitalsignet.com. Include the URL, the claim you are challenging, and the primary source you believe corrects it. Five-business-day SLA on substantive corrections. We do not credit corrections by default; flag in your message if you would like a credit line.
We do not respond to product-promotion requests on /methodology or /about. Brands wanting product placement consideration should pitch products on fit-to-type merits and accept that named-with-reasoning placement is the only placement we offer, and that it is not for sale.