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A complete guide to hair curl pattern classification — the biology behind curl pattern, what the Andre Walker and LOIS typing systems measure, why curl type alone is a poor predictor of hair needs, and what characteristics actually determine the right products and techniques.
· By MedSpot Editorial · 7 min read
Curl typing systems are among the most widely referenced frameworks in natural hair care — and among the most misapplied. Understanding what curl pattern classification actually measures (and what it doesn't) is essential for making sense of product recommendations, choosing appropriate techniques, and stopping the hunt for advice based on a number that may not predict your hair's behavior at all.
Curl pattern is determined by follicle geometry — specifically, the cross-sectional shape of the follicle opening and the curvature of the follicle tube beneath the scalp.
Round follicle: Grows a round-cross-section shaft perpendicular to the scalp → straight hair (Type 1)
Slightly oval follicle, slight curvature: Produces a mildly asymmetric shaft that waves as it grows → wavy hair (Type 2)
Oval follicle, curved follicle tube: Produces an oval or ribbon-shaped shaft growing in a defined helical path → curly hair (Type 3)
Highly elliptical or kidney-shaped follicle, tightly curved follicle tube: Produces a very flat, ribbon-like shaft growing in tight coils or zig-zag patterns → coily/kinky hair (Type 4)
The curl pattern encoded in the follicle is genetic and permanent. No topical product changes the follicle geometry. Chemical relaxers alter the curl of the already-grown shaft by breaking and reforming disulfide bonds — but new growth always emerges with the follicle's native curl pattern.
Individual variation within a single head: Most people have multiple curl patterns across their scalp. The temporal regions often have looser curls than the nape; the crown may be tighter. A single type number rarely describes the full picture.
Popularized by Oprah Winfrey's hairstylist Andre Walker in his 1997 book, this is the most widely referenced curl classification in natural hair communities:
| Type | Description | Sub-types |
|---|---|---|
| 1 | Straight — no curl; hair lies flat from root to end | 1a (very fine/thin), 1b (medium), 1c (coarse) |
| 2 | Wavy — S-shaped wave pattern, lies closer to the head | 2a (loose S), 2b (more defined S), 2c (strong wave approaching curl) |
| 3 | Curly — defined spiral or ringlet pattern; springs back when stretched | 3a (loose, large-diameter spirals), 3b (medium spirals), 3c (tight corkscrews) |
| 4 | Coily/kinky — very tight coils or zig-zag pattern; high shrinkage; often dry | 4a (tight coils with visible S-pattern), 4b (z-pattern, less defined coil), 4c (very tight, minimal definition) |
The Andre Walker system was developed by a professional stylist for use in his salon as a communication shorthand — a way to roughly classify clients' curl patterns to guide styling product selection and technique. It was not developed as a scientific classification for predicting hair biology or product chemistry needs.
Developed within the natural hair community as an alternative that attempts to capture characteristics beyond curl shape:
L — Line: The hair has bends and folds with no curve → primarily describes 4b/4c z-pattern
O — Circle: The hair forms complete or nearly complete circle loops → tight coil patterns (4a, some 3c)
I — Intact/straight: Hair grows straight or nearly straight → 1s and some 2s
S — Spiral/wave: Hair forms an S-shaped wave or curl → 2s and 3s
The LOIS system is less widely used in practice. It adds some distinction at the coily end of the spectrum but remains primarily a shape descriptor.
The practical limitation of curl-type-based advice is that curl pattern explains less about hair behavior than the three characteristics below. A proper hair assessment considers all of them.
How readily the cuticle absorbs and releases moisture — the single most important characteristic for product selection:
Porosity can be assessed by observation (how fast hair wets, how quickly it dries, how products behave). Curl pattern does not determine porosity.
Individual strand diameter — separate from how many strands you have:
Strand thickness is assessed by rolling a single strand between two fingers (fine hair barely registers; coarse hair is clearly tactile) or by comparing to a piece of thread.
The number of hairs per square centimeter of scalp:
Density is assessed by looking at how much scalp is visible on an unparted section of dry hair.
| Characteristic | How to assess | What it changes |
|---|---|---|
| Porosity | Wetting speed, drying speed, product behavior | Product weight, protein use, sealing method |
| Strand thickness | Feel of single strand, comparison to thread | Product weight, protein tolerance, moisture intensity |
| Density | Scalp visibility in unparted dry hair | Product quantity, style volume expectations |
| Curl pattern | Visual shape | Styling technique, elongation vs. definition methods |
| Scalp type | Sebum production, condition | Washing frequency, scalp-specific treatments |
Curl pattern matters for styling decisions — how to define, elongate, stretch, or set a curl. But when someone asks "what products does my hair need?" — porosity, strand thickness, and density answer that question far more accurately than curl type number.
A common experience in natural hair communities: spending significant time trying to accurately assign a type number, then following product advice for that type number, and finding the products don't work. This is often because:
The better approach: Assess all five characteristics in the table above. Read ingredients for functionality (humectants, emollients, occlusives, proteins, film-formers) rather than purchasing by type-matching. Experiment systematically, one variable at a time.
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