Hair loss is incredibly common — it affects around half of all men and women at some point in their lives. Understanding why it happens is the first step to finding the right treatment. Most hair loss is gradual, predictable, and — when treated early — manageable.

Anagen
Active growth phase. Each hair grows from the follicle for 2–6 years, getting longer every month.
 
Catagen
A short transitional phase lasting 2–3 weeks. The hair stops growing and detaches from its blood supply.
 
Telogen
Resting phase lasting ~3 months. The old hair sheds and a new one begins to grow in its place.

Losing 50–100 hairs a day is completely normal — this is simply your hair cycle working as it should. Hair loss becomes a concern when follicles shrink, the cycle shortens, or large numbers of hairs shed at once.

The most common cause: pattern hair loss

This is by far the most common reason people lose their hair, affecting up to 50% of men by age 50 and a significant proportion of women too. It is caused by a combination of genetics and the hormone DHT (dihydrotestosterone) — a more potent form of testosterone.

Step 1
An enzyme called 5-alpha reductase converts testosterone into DHT in the scalp
Step 2
DHT binds to receptors in genetically sensitive hair follicles, gradually shrinking them
Step 3
Shrunken follicles produce thinner, shorter hairs — and eventually stop producing hair altogether
This process is called follicular miniaturisation. The key point: the follicle is still alive — it has just been suppressed. This is why treatments like finasteride (which blocks DHT production) and minoxidil (which stimulates follicle activity) can be effective, especially when started early.

Stress & illness
Major physical or emotional stress can push large numbers of hairs into the resting phase at once, causing a sudden surge in shedding 2–3 months later. This is called telogen effluvium. It is usually temporary and self-limiting.
 
Hormonal changes
Pregnancy, childbirth, menopause, stopping the contraceptive pill, and conditions like PCOS can all trigger temporary or longer-term hair shedding due to shifts in oestrogen and androgen levels.
 
Nutritional deficiency
Low iron (ferritin), vitamin D, zinc, or inadequate protein intake can all impair hair growth. A crash diet or significant weight loss is a well-recognised trigger for temporary shedding.
 
Thyroid conditions
Both an underactive (hypothyroidism) and overactive (hyperthyroidism) thyroid can disrupt the hair growth cycle, causing diffuse shedding across the scalp. Treating the thyroid condition usually allows hair to recover.
 
Alopecia areata
An autoimmune condition in which the immune system mistakenly attacks hair follicles, causing sudden patchy hair loss. It can affect the scalp, eyebrows, and other areas. Treatment is available — speak to our pharmacist.
 
Medications
Certain medications — including some blood thinners, antidepressants, retinoids, beta-blockers, and chemotherapy agents — can cause hair shedding as a side effect. This is often reversible once the medication is reviewed.

⚠
When to seek further advice: If your hair loss is sudden, patchy, associated with scalp pain, redness or scarring, or accompanied by other symptoms such as fatigue, weight changes, or irregular periods — please speak to a GP or dermatologist. These could indicate an underlying medical condition that needs assessment.

The sooner you start, the better the results
Most hair loss — especially pattern hair loss — responds best to treatment started early, before follicles are permanently lost. Our GPhC-registered clinicians can help you identify the right treatment for your type of hair loss and get started today.

Treatments available include:

• Finasteride
• Topical minoxidil
• Oral minoxidil