The Norwood Scale (also known as the Hamilton–Norwood Scale) is the most widely used system for identifying and classifying the stages of male pattern baldness. Since hair loss in men usually follows predictable patterns that progress over many years, the Norwood Scale offers a simple visual guide to help illustrate how thinning and balding typically develop.
Although the Norwood Scale is the most recognised tool for male hair loss, it isn’t the only one. Various other classification systems are used by clinicians, researchers, and hair-restoration specialists—some designed for both men and women, and others created specifically to assess female pattern hair loss.
Despite these alternatives, the Norwood Scale remains the standard reference in clinical settings. It helps professionals accurately assess the severity of hair loss, guide conversations about treatment options, and track how well different hair-loss treatments are working over time.
Understanding the Seven Stages of the Norwood Hair Loss Scale
The Norwood Scale is divided into seven distinct stages, each outlining a different level and pattern of male hair loss.
Stage 1 – Little to no visible hair loss. The hairline remains unchanged, showing no recession.
Stage 2 – Mild recession begins around the temples. This is often referred to as a mature or adult hairline and is still considered normal.
Stage 3 – The first noticeable stage of male pattern baldness. The hairline recedes more deeply at the temples, forming an M-, U-, or V-shaped pattern. The affected areas may be bare or only lightly covered with hair.
Stage 3 Vertex – The frontal hairline remains similar to Stage 2, but significant thinning or balding appears on the crown (the vertex).
Stage 4 – Both the temple recession and the crown thinning become more pronounced. A thin band of hair still separates the two balding regions, connecting the sides of the scalp.
Stage 5 – Hair loss intensifies. The balding areas at the front and crown enlarge further, and the band of hair between them becomes much narrower and less dense.
Stage 6 – The frontal and crown balding areas merge, creating one larger area of hair loss across the top of the head. Only the sides and back retain noticeable hair.
Stage 7 – The most advanced stage of male pattern baldness. Only a thin band of hair remains around the sides and back of the scalp. This remaining hair is often fine and not very dense.
Norwood Class A Variant
There is also a less common variation known as Norwood Class A. In this pattern, the hairline recedes uniformly from front to back without forming an island of hair in the middle. Unlike the typical Norwood progression, the crown does not initially bald; instead, the recession moves straight backward from the front.
How Does Hair Loss Appear at Each Stage?
How Do Specialists Diagnose Male Pattern Baldness?
Diagnosing male pattern baldness typically involves a simple combination of a physical examination and a review of your medical history. In many cases, the pattern of thinning alone is enough to confirm the condition. However, if you’re younger, female, or experiencing hair loss that doesn’t follow the usual pattern, your doctor may investigate other potential causes.
A dermatologist or hair-loss specialist will closely examine your scalp to assess the pattern, density, and extent of shedding. They may also gently pull on a few hairs to evaluate how easily they come out and inspect the follicles for signs of underlying issues.
How Is Hair Loss Treated in the UK?
Starting treatment early is key. It’s usually much easier to slow down ongoing hair loss than to stimulate significant regrowth. Over time, hair follicles that stop producing hair can become dormant, and once thinning becomes advanced, surgical options often offer the most effective results.
Non-Prescription Treatments
Minoxidil
Available over the counter in the UK, minoxidil is applied directly to the scalp. It can slow further hair thinning and may encourage some new growth. It is often used long-term and can be combined with other treatments.
Low-Level Laser Devices
Devices such as laser combs, brushes, and helmets are marketed to stimulate growth. Some users report improvements, but large-scale clinical evidence remains limited.
Prescription Treatments
Finasteride
Finasteride is an oral medication that reduces levels of DHT, the hormone largely responsible for male pattern baldness. In the UK, it is typically accessed through private clinics or online pharmacies rather than through the NHS.
Most men need to take it consistently for several months to notice improvements, and benefits usually reverse once treatment stops. Possible side effects include reduced libido and erectile dysfunction, so medical guidance is important.
Surgical and Procedural Treatments
Hair Transplantation
A widely used surgical option in the UK. Hair follicles are taken from areas with strong growth—typically the back and sides of the scalp—and transplanted into areas that are thinning or balding.
Scalp Micropigmentation
A non-surgical cosmetic technique where tiny pigment dots are applied to the scalp to give the appearance of a fuller head of hair or a clean, shaved look.
Scalp Stretching or Reduction
Less commonly used today, but still an option in selected cases. These procedures involve stretching or removing areas of bald scalp, sometimes combined with hair transplantation to improve overall coverage.
Why Does Male Pattern Hair Loss Occur?
Male pattern hair loss develops due to a mix of genetic, hormonal, and environmental influences. The tendency to lose hair is inherited from both parents, and your genes determine how sensitive your hair follicles are to androgens—particularly dihydrotestosterone (DHT).
How Hair Growth Normally Works
Every hair grows from a follicle and goes through a natural cycle: a growth phase lasting two to six years, followed by a resting phase, after which the hair sheds and a new one begins to grow. This cycle continues throughout your life.
The Role of DHT in Hair Thinning
When DHT interacts with sensitive follicles, it disrupts this cycle. Growth phases become increasingly short—sometimes lasting only weeks or months. Over time, the follicles undergo miniaturisation, producing hairs that are progressively finer, shorter, and less pigmented. Eventually, the follicles shrink so much that they can no longer produce visible hair.
Can Male Pattern Hair Loss Be Prevented?
Preventing hair loss is closely linked to treating it early. Men begin losing hair at different ages and progress at varying speeds, so the decision about when to start preventative treatment is personal. Acting sooner generally offers the best chance of slowing or stabilising thinning.
Early Treatment Options
Medications such as minoxidil and finasteride remain the most common preventative treatments. For many men, these options can help slow down hair loss and, in some cases, encourage regrowth—especially when started at the first signs of thinning.
Key Takeaway
The Norwood Scale is a helpful tool for assessing the severity of male pattern hair loss and guiding treatment discussions. In the early stages, non-surgical treatments can be effective at slowing or preventing further thinning. At more advanced stages, a range of surgical options may provide the best long-term results.
