Hair loss scales, hairlines and how to classify your own hair loss

Key takeaways

• Some temple recession after puberty is almost universal and is not, by itself, balding. In an Australian town survey, 98.6% of adult men and 64.4% of adult women had bitemporal recession, while none of 140 children did Gan and Sinclair 2005. Norwood treated type III, not type II, as the minimum extent of hair loss to count as baldness Gupta and Mysore 2016.
• The famous scales are crude. Dermatologists grading the same photos agree only moderately on Norwood-Hamilton stage (intraclass correlation 0.63-0.68) and agree poorly with themselves three months later Guarrera 2009. Treat a stage as a rough band.
• Men can stage themselves roughly, not exactly. Self-ratings matched a trained observer exactly only 48-55% of the time (kappa 0.39-0.46) Taylor 2004, and agreement was kappa 0.47 with a three-category picture scale Littman and White 2005.
• Women seeking help tend to under-rate their own loss compared with their dermatologist Biondo 2004.
• Women usually lose hair in a different pattern from men: diffuse thinning over the crown with the front hairline kept, a widening centre part, and often a "Christmas tree" pattern where thinning gets worse towards the front. Full male-type recession is uncommon in women Ramos and Miot 2015. Use a part-width scale (Sinclair, Ludwig, Savin), not Norwood.
• Ancestry changes both how common pattern loss is and how it looks. Korean, Chinese and Taiwanese men have lower rates at each age than white men, and more of them keep the front hairline and lose hair at the crown or in a female-like pattern, which Norwood handles poorly. BASP was designed for this Paik 2001, Wang 2010, Lee 2007.
• Visible thinning is about thinner hairs as well as fewer hairs. Fine-haired people show scalp sooner Vecchio 2002, Birch 2001.
• The "you lose 50% before you notice" rule is not well supported. When people compared standardized scalp photos side by side, they could detect a density difference of about 23% (41.7 hairs/cm2), similar to dermatologists, and having alopecia made no difference Oh 2025. Slow change seen in a mirror is a harder task.
• Pattern hair loss is common and rises with age in both sexes. A guideline cites up to 80% of white men and 42% of women over a lifetime Kanti 2018. About half of postmenopausal women in one Thai study had female pattern hair loss, mostly mild Chaikittisilpa 2022.
• Red flags mean "see a doctor", not "pick a stage": a hairline receding as a band with eyebrow loss, patches, redness or scaling, sudden diffuse shedding, loss along the edges with tight styles, or hair loss with signs of high androgens in women.

Why scales exist

Pattern hair loss (androgenetic alopecia) progresses slowly through fairly predictable shapes. Scales turn those shapes into stages so clinicians and researchers can describe severity. None measures the biology directly (thinning shafts, fewer hairs per cm2, shorter growth phases); they capture the visible result. Most were built from small single-ancestry samples, and few were validated before wide use Gupta and Mysore 2016, Wirya 2017. One paper states that no classification, including Norwood-Hamilton, had been validated for population studies Khumalo and Gumedze 2012.

The main scales

Older scales (Beek, Ogata, Setty, Bouhanna, Ebling and Rook, Savin) are summarized in Gupta and Mysore 2016.

Norwood-Hamilton in plain language

Norwood revised Hamilton's scale using 1,000 white men and reported how often each stage occurred at each age Norwood 1975. The stages below are paraphrased from reviews Gupta and Mysore 2016, Wirya 2017.

• I: little or no recession.
• II: small, usually symmetrical triangles of recession at the temples.
• III: deep temple recessions that are bare or sparsely covered, the minimum that counts as baldness. III-vertex: loss mainly at the crown.
• IV: deeper front recession plus a sparse or bald crown, separated by a band of moderately dense hair.
• V: the band narrows and thins and both bald areas grow.
• VI: the bridge is gone and front and crown merge.
• VII: only a horseshoe fringe of often fine, sparse hair remains at the sides and back.
• Type A variants (IIA-VA): the hairline moves back as a whole front without a central island of hair or a separate bald crown. Norwood found this in about 3% of men Wirya 2017, but a later US sample of men aged 18-49 put it at 12% Rhodes 1998 (industry-sponsored).

Women: part-width scales

Women with female pattern hair loss usually notice a more visible centre part and a thinner ponytail before they see scalp Ramos and Miot 2015. Clinically there are three presentations: diffuse thinning over the top and crown with the front hairline preserved; the same with a triangle of thinning widening towards the front; and, more rarely, male-like bitemporal recession.

In 207 women with chronic diffuse hair loss who had triple scalp biopsies, a mid-scalp grade of 3-5 on the Sinclair photos meant pattern loss in 97% of cases. Grades 1-2 were split: 60% pattern loss and 37% chronic telogen effluvium Sinclair 2004. So a clearly widened part is a strong sign of pattern loss, while shedding with a near-normal part is ambiguous and worth a dermatologist's look.

Consensus authors point out that by Ludwig I a woman has already lost a significant volume of hair, and treatments are better at halting loss than restoring density, which argues for acting earlier Harries 2016.

BASP: one scale for everyone

BASP was developed by the Korean Hair Research Society on 2,213 patients (1,768 men and 445 women) at 13 centres Lee 2007. The basic type describes hairline shape: L (straight), M (temples recede more than the middle, grades 0-3), C (the whole front recedes in a half-circle, grades 0-3) or U (past the crown, grades 1-3). The specific type describes density: F (the whole top, grades 1-3) and V (the crown, grades 1-3). Because it separates hairline from density, it can code a woman's diffuse thinning, an Asian man's crown-only loss and a classic Norwood pattern on one scale. A 2020 modification added frontal grades but was less accurate (71.4% vs 82.5%) and harder to use Kim 2020.

How reliable are the scales in expert hands?

• Norwood-Hamilton: 7 dermatologists and 16 residents graded 43 photos with an ICC of 0.63-0.68; re-grading 56 photos three months later showed poor repeatability Guarrera 2009.
• BASP versus Norwood: 40 raters graded 100 photo sets, and agreement ran BASP basic type, then BASP specific type, then Norwood Hong 2013.
• Adapted Norwood: ICC rose from 0.68 to 0.76 for dermatologists, and exact agreement among them from 62-69% to 93-100% Khumalo and Gumedze 2012.

A one-step difference in Norwood stage between two people, two raters or two photos of the same person is within normal measurement noise.

How well can people stage themselves?

People are consistent with themselves and good at broad categories (none, temples, crown, both). They are mediocre at exact stages.

What photos can and cannot show

• They can show hairline shape and symmetry, depth of temple recession, a visible crown patch, the width of a centre part and obvious scalp show-through.
• They cannot reliably show early miniaturization and density changes that have not yet changed the outline. In 109 men, back-of-head density stayed around 127/cm2 across Norwood classes, while parietal density fell from 138 to 47/cm2 Vecchio 2002. A dermatoscope is needed to see variation in hair diameter. An algorithm applied to trichoscopy images sorted mild from moderate-severe disease with 90% test accuracy Di Fraia 2023.
• How much change is visible? With standardized global photos shown side by side, 205 people needed a density difference of about 41.7 hairs/cm2, or 22.8%, to tell two scalps apart, similar to the roughly 21% reported for dermatologists Oh 2025, Buontempo 2024.
• AI staging: a 2025 model trained on 761 images from 257 patients found hair-loss regions with high precision and graded I, II, IV and VI well but intermediate grades less consistently Xi 2025. A 2026 systematic review of 15 AI trichology studies found mostly retrospective, single-source datasets with limited external validation Alanazi 2026.
• Standardization matters. Experts recommend an identical setup at each photo session Canfield 1996 and rate global photography among the most valuable tools for tracking hair growth Chamberlain and Dawber 2003. See taking a good hair photo.

Mature hairline versus receding hairline

What the evidence supports:

• Bitemporal recession is the adult norm, not a disease marker: 98.6% of adult men and 64.4% of adult women, but 0 of 140 children aged 5-9. Depth of recession is what predicts pattern loss, not presence Gan and Sinclair 2005.
• Front-only recession is common and does not appear to progress with age. Among 1,390 Australian men aged 40-69, 31-33% had frontal-only loss in every age band, while crown or full loss rose from 31% to 53% Severi 2003.
• Hairlines change shape from childhood to adulthood, from a flatter juvenile line to an adult one Rassman 2013.
• Popular rules of thumb exist, such as the adult hairline settling between about ages 17 and 27 and sitting about 1-1.5 cm above the highest forehead crease. These come from expert opinion and no population study has validated them, so use them only as a rough guide.

Normal hairline shapes vary a lot, so an "M" shape alone is not loss:

• Turkish young adults (n=200): the M-shaped contour was the most common in men, around 46%, and occurred in 19% of women Sirinturk 2017. The published male percentages add up to more than 100%, so treat them as approximate.
• Korean men without loss (n=108): 70% had a linear hairline Koo 2000.
• Chinese young men (n=1,000): 48.7% linear, 27.9% linear with a central point, 9.8% round and 13.7% round with a central point Bao 2018.
• Women (n=360): 81% had a widow's peak and 98% had lateral "mounds" Nusbaum and Fuentefria 2009.

Only the first two rows are directly supported by data; the miniaturization row rests on clinical reasoning plus Vecchio 2002.

What normal age-related change looks like

Men:

Women:

Female pattern loss often starts in the reproductive years, with demand for treatment peaking at 25-40 and again around menopause. There are no population studies in women of African ancestry Ramos and Miot 2015.

Look-alikes a scale will mislabel

• Frontal fibrosing alopecia: a scarring, band-like frontotemporal recession, often with eyebrow and body hair loss, mostly in postmenopausal women Alenezi 2026. Eyebrow loss plus a receding hairline is a red flag. See frontal fibrosing alopecia.
• Traction alopecia: loss along the front and temple rim from tight styles. Short retained hairs along the rim (the "fringe sign") were present in 100% of women whose traction involved the marginal hairline Samrao 2011. It is reversible early and scarring later Akingbola and Vyas 2017. See traction alopecia.
• Telogen effluvium and diffuse alopecia areata: diffuse shedding. A hair-pull test positive all over the scalp points here, whereas in pattern loss it is positive only over thinning areas Ramos and Miot 2015. See telogen effluvium.
• Raised androgens in women: most women with pattern loss have normal androgens, but menstrual changes, infertility, excess body hair, acne, oily skin or a deepening voice need medical evaluation Ramos and Miot 2015.

What it means for your hair

• Sex: men are usually staged with Norwood or BASP and women with Sinclair, Ludwig or Savin plus the Olsen pattern. Some women show male-type temple recession and some men, especially East Asian men, show a female-like diffuse pattern Paik 2001. BASP works for both.
• Ancestry: East Asian men have roughly half or less the pattern-loss prevalence of white men at any age, more often keep the front hairline and lose hair at the crown, so a Norwood-only view under-detects their loss. For African-ancestry hair there are few population data, and recession at the edges with tight styles should raise traction alopecia before pattern loss Samrao 2011.
• Strand thickness: fine-haired people look more advanced at the same follicle count, so rely more on change over time than on one photo Vecchio 2002. See strand thickness.
• Density: normal density in women follows a bell curve, and many women with pattern loss still fall within the normal range Birch 2001. See hair density.
• Curl and length (our inference; no direct study): curly, coily or long hair covers the scalp more and can hide early crown or part changes. Use dry, unstyled hair, a centre part and a top-down crown view.

Myths and facts

• "Any temple recession means I'm balding." Nearly all adult men and most women have some Gan and Sinclair 2005. Depth, progression, miniaturization and crown change matter.
• "A mature hairline never moves again." Frontal-only loss was stable across age bands in men aged 40-69, but crown and full loss kept rising with age Severi 2003.
• "Norwood stage is an exact measurement." Dermatologists agree only moderately and repeat themselves poorly Guarrera 2009.
• "You must lose 50% of your hair before anyone can see it." We could not trace the source of this figure. In side-by-side standardized photos, a difference of about 21-23% was detectable Oh 2025.
• "Women don't get pattern hair loss." About 19-38% of older white women in clinic and community samples, and 52% of postmenopausal Thai women in one study Birch 2001, Chaikittisilpa 2022.
• "Asian men don't go bald." It is less common and more crown-predominant, but rises to 41-47% in men over 70 in Korean and Chinese studies Paik 2001, Wang 2010.
• "Women overestimate their hair loss." In the one study testing this, women awaiting treatment under-rated it Biondo 2004.

How to classify your own hair loss

1. Set up comparable photos. Use dry, clean hair with no product, and the same place, light, distance and camera each time Canfield 1996. Take the front with hair pushed back, both temples at about 45 degrees, the top from above with a centre part, the crown from above and behind, and the back of the head as your own unaffected reference.
2. Men, look at three things separately, as BASP does. Hairline: straight or a small even "M" is normal or mature (Norwood I-II); deep bare or sparse temple triangles are Norwood III or deeper; the whole front moving back evenly is a Type A or BASP C pattern. Crown: compare a top-down crown photo with the back of your head; a growing visible gap suggests III-vertex or higher. Change over time: compare with your own photos from about age 17-18, since men recall past hair consistently Littman and White 2005, and recheck every 6-12 months with identical photos.
3. Women, look at the centre part and compare it with a part made at the back of the head. Sinclair 1-2 is a normal or slightly wider part (ambiguous if you are also shedding). Sinclair 3 is a clearly wider part with less volume at the sides. Sinclair 4-5 is diffuse thinning over the top with scalp easily visible. Note whether the widening forms a triangle towards the forehead and whether your ponytail has become thinner.
4. Think in bands, not numbers: none or mature; early (Norwood III or III-vertex, or Sinclair 2-3); moderate (Norwood IV-V, or Sinclair 3-4); advanced (Norwood VI-VII, or Sinclair 5).

When to see a dermatologist

• Soon, without waiting for change: eyebrow loss with hairline recession; a smooth, shiny or scarred-looking band at the hairline; patches of complete loss; redness, scaling, pustules, pain, burning or itching; sudden heavy shedding; loss along the hairline if you wear tight styles; and in women, irregular periods, acne, excess body or facial hair or other signs of high androgens Alenezi 2026, Samrao 2011, Ramos and Miot 2015.
• Worth an appointment: any progression documented on identical photos; Norwood III or more or any crown thinning if you want to slow it; a widening part in a woman, since treatments mainly preserve rather than restore density Harries 2016. See when to see a dermatologist.
• Probably fine to monitor: a small, symmetrical temple recession unchanged on photos for a year, with no crown thinning and no fine hairs at the edge.

Bottom line

Hair loss scales are rough bands, not measurements, and even experts disagree by a stage. Compare identical photos over time, pay attention to the crown, part width and fine hairs at the edges, and treat a mature hairline and early recession as different things based on depth and change. Seek medical advice for the red flags above. Treatments are covered in finasteride and minoxidil.