Male pattern baldness affects roughly 50% of men by age 50 and 85% by age 70, according to research published in the Journal of Investigative Dermatology. The process is predictable enough that dermatologist James Hamilton and later O’Tar Norwood developed a classification system that still guides clinical decisions today.
Understanding where you are in the Norwood Scale matters not just for knowing what your hairline looks like now, but for understanding what treatments are most likely to work at your specific stage.
What Drives the Progression
Before the stages, the mechanism. Male pattern hair loss is driven by dihydrotestosterone (DHT), a potent androgen derived from testosterone through the action of an enzyme called 5-alpha reductase.
DHT binds to androgen receptors in genetically susceptible hair follicles. Over time, this binding gradually shrinks the follicles through a process called miniaturization. Hair produced by miniaturized follicles becomes finer, shorter, and lighter-colored with each growth cycle until the follicle stops producing visible hair entirely.
The susceptibility is genetic and concentrated in the frontal scalp and crown. Hair on the sides and back of the head lacks the same androgen receptor density, which is why those areas remain in even advanced hair loss. This is also why hair transplant surgery works: donor hair from the sides and back retains its DHT resistance even when moved to the top.
The Seven Norwood Stages
Stage 1 is the baseline: no significant recession or thinning. This is the starting point, not a diagnosis.
Stage 2 is the first sign of change. The hairline shows a slight recession at the temples, forming an early M or V shape. Many men experience this in their mid-to-late twenties and do not notice it for months. The recession is minimal and often requires a close look in good lighting to see.
Stage 3 is where most men first seek medical advice. The temple recession has deepened noticeably. Two distinct curves now mark where the hairline was once straight. Some Stage 3 variants also show early crown thinning, classified as Stage 3 Vertex. Treatment started at Stage 3 has the best evidence for halting or partially reversing the process.
Stage 4 combines more significant frontal recession with thinning at the crown. A band of hair still separates the two areas, but the top of the scalp is visibly thinner when viewed from above. This stage often progresses faster than earlier stages.
Stage 5 is similar to Stage 4 but with a thinner, narrower band of hair between the receding front and thinning crown. The two affected areas are converging. Treatment at this stage can slow progression but full reversal becomes less realistic.
Stage 6 means the band has disappeared. The frontal recession and crown thinning have merged into a single large area of hair loss across the top of the scalp. Only the sides and a low band at the back remain. At this stage, medication can maintain what remains, but regrowth of the fully lost area is not typically achievable with medication alone.
Stage 7 is the most advanced. Only a thin horseshoe-shaped band of hair remains around the sides and lower back of the head. This is the endpoint of male pattern hair loss.
Treatment Options by Stage
Stages 1-3 are the window where the best outcomes from medical treatment are achievable. Two medications have solid evidence.
Finasteride (1 mg daily) is a 5-alpha reductase inhibitor that reduces DHT production by roughly 70% in the scalp. Clinical trials show it halts or reverses hair loss in about 83-90% of men who take it for two years. Regrowth is possible at these earlier stages. Results require ongoing use; stopping the medication reverses the effects within 6-12 months.
Minoxidil (topical 5% solution or foam, twice daily) extends the anagen growth phase of the hair follicle and increases follicle size. It works through a different mechanism than finasteride and is often used alongside it. Results take 4-6 months to become visible, and many men experience an initial shedding phase in the first two months that is frequently misread as the treatment making things worse. This shedding is normal.
Stages 4-5 can still benefit from medication to slow progression, though full regrowth is unlikely. Hair transplant surgery becomes a more serious option at these stages for men who want to restore density to the affected areas.
Stages 6-7: Medication at this point maintains what remains. Transplant surgery is the main tool for restoring coverage if that is the goal. The sides and back still provide viable donor hair.
A dermatologist or trichologist can accurately stage your hair loss and help set realistic expectations for what treatment can achieve. Starting earlier consistently produces better outcomes, which means not waiting until the loss is obvious.
For a detailed look at finasteride’s side effects beyond the clinical headlines, see Finasteride Side Effects: What the Research Actually Shows. For the minoxidil timeline month by month, see How Long Does Minoxidil Take to Work?
