Hair Loss in Men: What Causes It?

How Common Is Male Hair Loss?

Hair loss in men is remarkably common — far more so than many men realise before it happens to them. Around 66% of men experience noticeable hair loss by the age of 35, rising to over 85% by the age of 50. Despite being so prevalent, many men delay seeking treatment — which matters enormously, because the earlier hair loss is treated, the more effectively it can be managed.

Male Pattern Baldness (Androgenetic Alopecia)

The vast majority of hair loss in men — estimated at around 95% of cases — is male pattern baldness, also known as androgenetic alopecia. It follows a recognisable pattern: the hairline gradually recedes at the temples, thinning spreads across the crown, and over years the two areas may merge into widespread baldness.

The condition is hereditary. If your father, grandfather, or maternal uncles experienced significant hair loss, your own risk is substantially elevated. However, the genetic component is polygenic — it comes from multiple genes on both sides of the family — so hair loss patterns can skip generations or differ markedly between relatives.

The Role of DHT in Male Hair Loss

Dihydrotestosterone (DHT) is a potent androgen hormone created when testosterone is converted by the enzyme 5-alpha reductase. In men genetically predisposed to hair loss, DHT binds to androgen receptors in the hair follicles of the scalp. This binding gradually miniaturises the follicle — each successive hair grows thinner, shorter, and paler, until eventually the follicle becomes dormant.

This is precisely why finasteride works so effectively: it inhibits 5-alpha reductase, reducing scalp DHT levels by up to 70% and halting the follicle miniaturisation process.

Other Causes of Hair Loss in Men

Stress and Hair Loss

Significant physical or emotional stress can trigger telogen effluvium — a temporary condition where a large number of follicles simultaneously enter the resting (telogen) phase, causing widespread shedding typically 2–3 months after the stressful event. This is common after illness, bereavement, surgery, or extreme weight loss. It usually resolves within 3–6 months.

Chronic stress, however, can perpetuate the condition. If you notice persistent diffuse hair loss alongside signs of anxiety, fatigue, or low mood, speak to your GP.

Diet and Nutritional Deficiency

Hair follicles are metabolically active tissue and require adequate nutrition. Deficiencies in iron (particularly common in men who eat little red meat), zinc, protein, and vitamin D are all associated with increased hair shedding. A blood test from your GP can identify deficiencies, which are easily corrected with dietary changes or supplementation.

When to See a Doctor

Treatment Options for Male Hair Loss

For the most common cause — male pattern baldness — there are two MHRA-approved treatments with strong clinical evidence:

• Finasteride 1mg — prescription-only oral tablet. Blocks DHT production. 85% improvement rate over 5 years. The first-line treatment.
• Minoxidil 5% — available over the counter. Applied topically twice daily. Stimulates follicles directly. Most effective when used alongside finasteride.

For non-genetic hair loss, treatment depends on the underlying cause: addressing nutritional deficiencies, managing thyroid conditions, or reducing medication where possible.