Hair type chart for men: what 1A to 4C really means, and which parts are science

You sit in the barber’s chair, he asks what your hair does, and you say “kind of wavy, maybe 2B?” That is exactly what the chart is good for, and also where it stops.

The 1A–4C chart describes a pattern well enough to start a conversation, but it is not a scientific measurement. It came from stylist Andre Walker in the 1990s to market hair-care products, and his own 2018 site listed no 3C or 4C. Below, every term is tagged by whether it is measured, merely descriptive, or not supported.

Key numbers

• kappa 0.418 — agreement among three raters using a measured eight-group curl system. Source
• 1,442 people in 18 countries — the sample used to derive eight measured hair categories. Source
• up to 95% heritability — an estimate for curliness in Europeans, alongside an AUC of 0.66 for DNA-based prediction. Source
• 0 PubMed records — returned for “float test” AND hair on 13 September 2026. Source
• about 45% straight, 40% wavy, 15% curly — an approximate distribution among people of European ancestry. Source
• about 0.35 mm a day — a textbook average for healthy scalp-hair growth. Source
• 63% — the share of Japanese breast-cancer survivors who reported wavier or wavy regrowth in one survey. Source

Table of contents

• Where did the 1A to 4C hair chart come from?
• What do the hair types mean for men?
• Is the hair type chart scientific?
• Why is some hair straight and some curly?
• What do fine, coarse and dense hair mean?
• What do porosity and frizz actually mean?
• Can your hair type change?
• How to cite this page
• The bottom line
• Sources

Where did the 1A to 4C hair chart come from?

The 1A–4C chart is a stylist-created classification that became common consumer language, not a clinical standard.

Andre Walker Hair Typing System

Descriptive. The Andre Walker system uses numbers for straight, wavy, curly, and coily hair, with letters for tighter subtypes. A 2026 review says Walker created it in the 1990s to market hair-care products; Walker’s archived site says it explained texture and product choice. The review notes that mainstream typing systems were generally not independently validated or intended for clinical use.

3C and 4C

Descriptive. 3C and 4C are labels, but neither appears on Walker’s 2018 Type 3 and 4 pages. Their community origin is undocumented, so treat them as shorthand rather than Walker categories. The archived source lists 3A, 3B, 4A, and 4B.

LOIS and FIA systems

Descriptive. LOIS classifies pattern, size, and texture, while FIA changes the letter subtypes and adds strand thickness and volume. The comparison review maps them.

Useful vocabulary, not a measurement instrument.

What do the hair types mean for men?

For a man choosing a haircut, the broad pattern is more useful than arguing over a letter. No type is the good one; the real upgrade is a cut that works with your pattern instead of fighting it.

Type 1 straight

Descriptive. Type 1 means hair that lies straight rather than forming a persistent wave or curl.

Type 2 wavy

Descriptive. Type 2 means hair that forms a wave, described as an S pattern. Once the S pattern dominates, a straight-hair haircut guide is less relevant.

Type 3 curly

Descriptive. Type 3 means hair that forms visible curls or loops rather than waves. Walker described 3A as loopy and 3B as smaller, coarser curls; the AAD advises against dry brushing and to condition the full length. Our curly-hair guide covers haircut decisions.

Type 4 coily

Descriptive. Type 4 means tightly coiled hair, with patterns that may look S-shaped or more Z-shaped. The American Academy of Dermatology says thick, curly hair is more prone to breakage and dryness, and should be washed at least every 2–3 weeks rather than necessarily daily or weekly.

Mixed texture

Descriptive. Mixed texture means curl pattern, density, or thickness varies across one head, so one label cannot describe every area.

Every row is convention, not measurement.

Is the hair type chart scientific?

Not in the measurement sense. Researchers describe curl with measured geometry such as curve diameter, curl index, waves and twists, and even those systems show rater disagreement.

Curve diameter

Measured. Curve diameter describes a hair’s bends and separates straight-side groups. Researchers measured hair from 1,442 subjects in 18 countries, but the published cut-offs sit behind a paywall, so we do not repeat them. The worldwide study used geometry, not ethnicity, to derive categories.

Curl index, waves and twists

Measured. Curl index compares relaxed with extended length, while waves and twists describe shape along the fibre. A separate study measured four curliness parameters across 2,449 subjects in 22 countries, showing that “curly” has several features.

Curl types I to VIII

Measured. The L’Oréal eight-type system uses curve diameter for types I–IV and curl index, waves, and twists for types V–VIII. It is more explicit than 1A–4C, but reviews say it may be hard to reproduce and misses some curly-hair diversity. A 2023 critical review argues the eight-type system may be too complex for reproducibility.

Cross-section shape

Measured. Cross-section shape describes whether a hair fibre is more circular or elliptical and relates to curl, but is not a barber’s visual label. Straighter fibres tend to be more circular and curlier ones elliptical; another study found no internal-structure difference across its populations.

Observer ratings

Measured. Trained observers can make broad straight, wavy, and curly judgements, but detailed subtype agreement is weaker. Three raters classified 480 hairs from 48 volunteers with kappa 0.418; no rater grouped every hair from a volunteer alike, while a twin-and-sibling study linked observer ratings to instruments. The observer comparison supports broad language, not perfect subtypes.

The instrument is not neutral: L’Oréal developed it, raters disagree, and the 2026 review disclosed L’Oréal-linked funding and consultancy.

Why is some hair straight and some curly?

Curl begins in the follicle, not in a styling label. Genes influence follicle shape, fibre geometry, and thickness, but DNA predicts curl poorly, so your hair itself is a better guide than any genetic test.

Curved follicle

Measured. A curved follicle and asymmetric bulb can produce a curved hair shaft, so the pattern is established before the fibre leaves the scalp. Biopsy work found curved follicles and retrocurvature in curly hair; curly follicles kept producing curved shafts in vitro, and the mechanism remains debated.

Hair shape genes

Measured. Hair shape is influenced by multiple genetic signals connected with the follicle and inner root sheath. TCHH variants were linked with straight hair in Europeans, EDAR with thickness in East Asian samples, and PRSS53 with scalp-hair shape in 6,630 Latin Americans; differing straight-hair links suggest at least two independent evolutions.

Heritability of curl

Measured. Heritability describes how much variation in a population is associated with genetic differences; it does not predict one person perfectly. Curliness reached up to 95% heritability in Europeans, yet a model across 28,964 subjects in 9 cohorts reached AUC 0.66 for straight versus non-straight hair.

Genes set structure, not destiny.

What do fine, coarse and dense hair mean?

Fine, coarse, and dense answer different questions. Fine or coarse describes the fibre; density describes how much hair is present.

Fine vs coarse hair

Descriptive. Fine and coarse describe strand thickness, but there is no universal micrometre cut-off. A study found “fine hair” also tracked density, strength, and volume, so barber and microscope descriptions may differ.

Hair density

Measured. Hair density is the amount of hair in a scalp area, not strand diameter. A study of 2,249 adults from 24 ethnic groups found differences in density, diameter, and growth; group averages are not a personal diagnosis.

Growth rate and anagen

Measured. Growth rate is how quickly the shaft lengthens; anagen is the active phase that helps determine maximum length. Healthy scalp hair grows about 0.35 mm a day; anagen lasts 2–6 years, shaping maximum length.

Hair whorl and cowlick

Descriptive. A whorl is the direction in which hair grows from a scalp centre; a cowlick is the styling problem that direction can create. The whorl-handedness genetic claim failed to replicate consistently, so use a cowlick styling guide, not a brain-theory label.

What do porosity and frizz actually mean?

Porosity is about how hair absorbs and retains water, products, and treatments; it is not a permanent curl category.

Hair porosity

Descriptive. Hair porosity describes how readily the fibre takes up and retains water and products, largely in relation to cuticle condition. Lab measurements show porosity rises with bleaching, UV exposure and even routine surfactant washing, so it is mostly a record of wear rather than a fixed type. Healthy hair is not waterproof either: a cosmetic chemist, citing a hair-science textbook, notes undamaged hair can absorb about 30% of its weight in water within minutes.

Float test

Not supported. The float test claims that a strand’s position in water identifies its porosity, but it has no peer-reviewed validation. PubMed searches on 13 September 2026 found zero records for “float test” AND hair; a cosmetic-chemistry source says it offers at best a general idea under controlled conditions.

Frizz

Descriptive. Frizz is a rough, irregular appearance or feel shaped by friction, humidity, and wear along the fibre.

Hydrogen and disulfide bonds

Measured. Hair’s keratin structure is held together by disulfide bonds and hydrogen bonds between protein filaments. Straighteners can break cortical disulfide bonds, while temperature and humidity change mechanics; the popular “humidity breaks hydrogen bonds” explanation is a plausible mechanism rather than a measured rule.

Breakage and knots

Measured. Breakage is fibre failure, and knots can create weak points that make curly and coily hair harder to handle. Microscopy found knots in 10%–16% of shafts from 12 African volunteers versus 0.15% in comparison hair; dermatology guidance links tight curls with dryness and breakage.

Heat damage

Measured. Heat can damage any hair type, especially the surface. In one in-vitro dryer study, surface damage rose with temperature; the AAD advises limiting blow-drying and irons.

Repairing hair

Not supported. “Repairing” hair is marketing language for coating or filling damaged cuticle, not biological healing.

Care advice need not make porosity a personality type; routine depends on condition and handling, not a float-test verdict.

Can your hair type change?

Hair can change in diameter, density, damage, and appearance, but the claim that curl pattern changes every year has no evidence either way in any study we found. A visible change need not prove permanent follicle change.

Chemo curls

Measured. Chemo curls are a reported texture change during regrowth after chemotherapy, not a normal annual hair-type cycle. Six months after regrowth began, 63% of Japanese breast-cancer survivors in one self-report survey reported wavier or wavy hair; all participants were women.

Hair changes with age

Measured. Age changes hair diameter and density, but no study we found tracks a predictable curl-pattern change. A review reports diameter rising until a mean age of about 40 and density declining from about 35.

Hair type changing every year

Not supported. We found no study for or against a universal yearly change in hair type.

Age and treatment can change appearance without proving a yearly follicle-pattern change.

How to cite this page

Suggested citation: Real World Appeal. “Hair type chart for men: what 1A to 4C really means, and which parts are science.” realworldappeal.com, September 2026. https://realworldappeal.com/blog/hair-type-chart-men

The primary studies and source pages are linked above and listed below so readers can cite them directly. Sources were retrieved 13 September 2026.

The bottom line

The 1A–4C chart works when you need a shared description. It fails as a system of universal thresholds: sources disagree, heads mix textures, and measured systems show rater disagreement.

The hair chart is a vocabulary, not a measurement. Use it to start the conversation, then describe pattern, thickness, density, damage, and where on your head each one shows up. If you want to see how your hair frames your face in a first impression, Real World Appeal’s free photo read can help — it is not a clinical or scientific instrument, but reads a photo’s impression rather than judging you.

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