Curl pattern guide: what the typing systems mean, what they don't, and what actually matters for your hair

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.

The biology of curl pattern

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.

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The Andre Walker typing system (1–4 with a/b/c subdivisions)

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) |

What the system was designed for

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.

What the system measures well

Visual curl pattern: The letter and number do capture the visible shape and looseness of the curl, which is useful for styling technique discussions (e.g., how to define or elongate a curl)
Communication baseline: Provides a shared vocabulary for discussing hair in the natural hair community

What the system does NOT reliably predict

Porosity: A 4c curl can be low, medium, or high porosity. Curl tightness does not equal porosity level.
Density: How many hairs per square centimeter — independent of curl pattern entirely
Strand thickness (diameter): Fine, medium, and coarse strand width occur across all curl types
Moisture needs: Determined by porosity, density, and strand thickness — not curl pattern number
Product performance: Two people with identical "3b" curl patterns may need entirely different products based on porosity and strand thickness

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The LOIS system (an alternative classification)

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.

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What actually predicts hair care needs

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.

Porosity

How readily the cuticle absorbs and releases moisture — the single most important characteristic for product selection:

Low porosity: Tightly sealed cuticle; water beads initially; products sit on top; benefits from heat during deep conditioning; avoid heavy proteins; lightweight humectant-rich products
Medium porosity: Balanced absorption and retention; tolerates most products
High porosity: Open/damaged cuticle; absorbs instantly; loses moisture quickly; needs sealing (LOC/LCO method); protein treatments to fill cuticle gaps; heavier occlusive products

Porosity can be assessed by observation (how fast hair wets, how quickly it dries, how products behave). Curl pattern does not determine porosity.

Strand thickness (diameter)

Individual strand diameter — separate from how many strands you have:

Fine: Smaller diameter; lower tensile strength per strand; prone to protein overload; may not tolerate heavy products; responds to lighter formulations
Medium: Mid-range diameter; tolerates most products and treatments
Coarse: Larger diameter; higher natural tensile strength; may resist penetration of lighter products; benefits from heavier, more emollient formulations; more resistant to protein overload

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.

Density

The number of hairs per square centimeter of scalp:

Low density: Fewer strands; scalp visible easily; heavier products weigh the hair down visually; styles may look thin
Medium density: Average number of strands
High density: Many strands; can support heavier products; styles appear full; detangling is more time-intensive

Density is assessed by looking at how much scalp is visible on an unparted section of dry hair.

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The practical framework: characteristics over type number

| 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.

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Why the typing obsession can be counterproductive

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:

Multiple patterns coexist: Assigning one number to a multi-texture head forces products chosen for one pattern onto areas with different needs
Porosity overrides pattern: A 3b with high porosity has more in common with a 4c with high porosity than with a 3b with low porosity
Products are marketed by type: The commercial hair care industry maps products to types because it creates a navigable purchasing decision — not because types determine product chemistry needs

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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