Hair Loss Treatment Prescribed by UK Doctors

Androgenetic alopecia (AGA) is the most common cause of hair loss in men, affecting approximately 30% by age 30, 50% by age 50, and 80% by age 70.

The condition follows the Hamilton-Norwood classification, progressing from temporal recession (Type II) through vertex thinning (Type III-IV) to extensive loss sparing only a horseshoe-shaped fringe (Type VI-VII).

The DHT mechanism underpins AGA pathology. Testosterone is converted to dihydrotestosterone by the enzyme 5-alpha reductase (type II isoform) within the dermal papilla of susceptible follicles.

DHT binds to androgen receptors with 5-fold greater affinity than testosterone, triggering progressive follicular miniaturisation — the gradual transformation of thick terminal hairs into fine, unpigmented vellus hairs.

Genetic predisposition determines which follicles express androgen receptor sensitivity.

The primary susceptibility locus maps to the androgen receptor gene on the X chromosome, explaining the maternal inheritance pattern observed clinically.

However, over 200 additional genetic loci contribute, making inheritance polygenic and complex.

Clinical assessment should differentiate AGA from other causes of alopecia:

• Telogen effluvium: diffuse shedding 2-4 months after physiological stress (surgery, illness, childbirth, crash dieting)
• Alopecia areata: well-circumscribed smooth patches, autoimmune-mediated
• Traction alopecia: hair loss along the hairline from chronic tension (tight hairstyles)
• Scarring alopecia: permanent follicular destruction from lichen planopilaris, discoid lupus, or folliculitis decalvans

Blood tests to exclude secondary causes include thyroid function (TSH), ferritin (target above 70 mcg/L), and in borderline cases, total and free testosterone, DHEA-S, and sex hormone-binding globulin.

Scalp biopsy is reserved for diagnostic uncertainty.

Early treatment preserves significantly more hair than delayed intervention because miniaturised follicles eventually lose their regenerative capacity permanently.

The sooner treatment begins after the onset of thinning, the better the long-term outcome.

Two evidence-based pharmacological treatments are available for AGA: finasteride (prescription-only) and minoxidil (available OTC and on prescription).

Combination use produces the strongest clinical outcomes.

Finasteride 1 mg daily inhibits type II 5-alpha reductase, reducing scalp DHT concentrations by approximately 70% and serum DHT by 65-70%.

• Hair count increase of 11% at 1 year and maintained at 5 years
• 90% of men show no further progression of hair loss
• 65% achieve visible regrowth assessed by photographic review
• Maximum benefit appears at 12-24 months of continuous use

Discontinuation leads to reversal of gains within 6-12 months as DHT levels return to baseline. Finasteride is therefore a long-term commitment.

Minoxidil 5% topical solution or foam, applied twice daily to the scalp, prolongs the anagen (growth) phase of the hair cycle and stimulates follicular blood flow via potassium channel opening and upregulation of vascular endothelial growth factor (VEGF).

It works independently of the androgen pathway.

Minoxidil produces visible improvement in 40-60% of men after 4-6 months.

An initial shedding phase (weeks 2-8) represents synchronised transition of resting hairs into active growth and is a positive prognostic sign.

The 5% formulation is 45% more effective than the 2% formulation for vertex hair regrowth.

Combination therapy (finasteride + minoxidil) targets both the hormonal and vascular pathways simultaneously.

A randomised trial published in Dermatologic Surgery showed the combination produced 12.7% greater hair count than finasteride alone at 12 months.

Emerging treatments include:

• Dutasteride 0.5 mg (dual 5-alpha reductase inhibitor): blocks 90% of DHT, slightly greater efficacy than finasteride but used off-label in the UK
• Low-level laser therapy (LLLT): FDA-cleared devices show modest benefit as adjunctive therapy
• Platelet-rich plasma (PRP) injections: early evidence is promising but not yet established in guidelines

The safety profile of hair loss treatments is well-characterised, and transparent discussion of side effects supports informed decision-making and adherence.

Finasteride sexual side effects are the primary concern for patients. Clinical trial data from the original registration studies reports:

• Decreased libido: 1.8% vs 1.3% placebo (NNH approximately 200)
• Erectile difficulty: 1.3% vs 0.7% placebo
• Reduced ejaculate volume: 0.8% vs 0.4% placebo

These effects resolve on discontinuation in the vast majority of cases.

The concept of "post-finasteride syndrome" (PFS) — persistent sexual, neurological, and cognitive symptoms after stopping the drug — has been reported in case series but lacks confirmation in controlled studies.

The MHRA and EMA continue to monitor reports and include PFS in patient information leaflets as a precautionary measure.

PSA impact: Finasteride reduces prostate-specific antigen (PSA) by approximately 50%.

Men undergoing prostate cancer screening should inform their clinician so PSA values can be adjusted (multiply by 2) for accurate interpretation.

Minoxidil side effects are predominantly local:

• Scalp irritation and dryness (10-15%), particularly with the alcohol-based solution
• Contact dermatitis: switch to the foam formulation, which is propylene glycol-free
• Unwanted facial hair (hypertrichosis): reported by 3-5%, especially with the liquid dripping onto the face
• Transient initial shedding (weeks 2-8): affects 20-30% and self-resolves

Systemic absorption of topical minoxidil is minimal (1-2% of applied dose) but can occasionally cause:

• Mild tachycardia or palpitations
• Dizziness or light-headedness
• Peripheral oedema (very rare)

Contraindications for finasteride include women of childbearing potential (teratogenic — causes feminisation of male foetus), severe hepatic impairment, and known hypersensitivity.

Minoxidil should be avoided in patients with uncontrolled hypertension or phaeochromocytoma.

Monitoring: no routine blood tests are required for finasteride at the 1 mg dose.

However, baseline liver function is advisable, and patients should report any breast tenderness or mood changes promptly.

Maximising the benefit of hair loss treatment requires correct technique, realistic expectations, and long-term consistency.

Based on clinical experience and published evidence, the following practical guidance helps patients achieve the best results.

Application technique for minoxidil significantly affects absorption and efficacy:

• Apply to a dry scalp, not damp hair — absorption increases 4-fold on dry skin
• Use the dropper to target thinning areas directly; spread with fingertips
• Allow 2-4 hours before washing hair or sleeping to ensure absorption
• Twice-daily application maintains steady-state follicular drug levels; once-daily dosing reduces efficacy by 30-40%
• Wash hands thoroughly after application to prevent unwanted facial or body hair

Timeline expectations prevent premature discontinuation:

• Months 1-3: initial shedding may occur; minimal visible change
• Months 3-6: shedding resolves, early vellus regrowth becomes visible
• Months 6-12: meaningful cosmetic improvement in 60-80% of combination users
• Months 12-24: maximum response achieved; ongoing treatment maintains gains

Nutritional optimisation supports healthy hair growth alongside pharmacotherapy:

• Ferritin below 70 mcg/L is associated with increased hair shedding; iron supplementation may benefit
• Biotin (vitamin B7) deficiency impairs hair quality, though supplementation in non-deficient individuals has limited evidence
• Zinc and selenium contribute to keratin synthesis; deficiency should be corrected if present
• Protein intake of 1.0-1.2 g/kg body weight supports the high metabolic demands of growing follicles

Scalp health influences treatment response:

• Seborrhoeic dermatitis (dandruff) creates chronic inflammation that may impair follicular function; treat with ketoconazole 2% shampoo
• Ketoconazole itself has weak anti-androgenic properties and may offer modest additive benefit in AGA
• Avoid harsh chemical treatments and excessive heat styling during the regrowth phase
• Regular scalp massage (4 minutes daily) showed increased hair thickness in a small Japanese study, though evidence remains preliminary