Hair loss prevention: what actually works, what does not, and when to start

Reviewed by The Wellness Team. Last reviewed October 2026.

Short answer: the two treatments with the strongest evidence for preventing pattern hair loss are minoxidil and finasteride, both licensed medicines in the UK, and both work best when started early. Platelet-rich plasma (PRP) has a growing evidence base as a drug-free option for people who cannot or prefer not to take daily medication. Most supplements, shampoos and oils marketed for prevention have weak or no evidence behind them. Whatever route you choose, the single most effective step is an early diagnosis, because almost every treatment works better on follicles that are still active.

Why prevention beats regrowth

Pattern hair loss (androgenetic alopecia) is a slow miniaturisation of the hair follicle. Each growth cycle produces a slightly thinner, shorter hair until the follicle eventually stops producing visible hair at all. Once a follicle has been dormant for years, no cream, tablet or injection reliably brings it back. Every effective treatment we have works by protecting follicles that are still alive. That is why dermatologists are so consistent on one point: the best time to treat hair loss is the moment you notice it, not after it has become obvious to everyone else.

The treatments with real evidence

Finasteride (prescription only). In the original phase III trials published by Kaufman and colleagues in the Journal of the American Academy of Dermatology (1998), finasteride 1 mg daily stopped further loss in the great majority of men and produced visibly improved growth in about two thirds by two years. It lowers scalp DHT, the hormone driving miniaturisation. A small minority of men report side effects, which is a conversation to have with a prescriber, not a reason to avoid the conversation. For women, finasteride is not suitable in pregnancy or if pregnancy is possible.

Minoxidil (over the counter). Topical minoxidil 5% is licensed for pattern hair loss and has decades of trial evidence behind it. It works best on the crown, less reliably on a receding hairline, and it only works while you keep using it. Expect an initial shedding phase in the first weeks; this is normal and settles.

Ketoconazole shampoo (adjunct). A 2019 systematic review of five human studies covering 318 people found modest signs of benefit for ketoconazole shampoo in pattern hair loss. It is a reasonable addition, not a standalone answer. We covered the evidence in detail in our ketoconazole guide.

PRP (drug-free option). A 2020 systematic review by Gentile and Garcovich in the International Journal of Molecular Sciences analysed the controlled trials of PRP for pattern hair loss and found consistent increases in hair density and hair thickness compared with control treatments. The honest caveat is that study protocols vary and larger standardised trials are still needed. In practice, PRP suits people who want a treatment without daily medication, or who did not tolerate finasteride or minoxidil. At our clinic a PRP session is £450, and a course of three sessions is £1,215.

What has weak or no evidence

Biotin and general hair vitamins only help if you have an actual deficiency. Caffeine shampoos have no meaningful human trial evidence for regrowth. Rosemary oil has exactly one small trial (Panahi and colleagues, Skinmed, 2015) comparing it with 2% minoxidil over six months, with modest results in both groups. Pumpkin seed oil has one trial of 400 mg daily over 24 weeks (Cho and colleagues, 2014) showing a modest improvement. Saw palmetto has a handful of small, low-quality studies. None of these are harmful to try, but none of them substitute for a treatment with real evidence, and relying on them while follicles quietly miniaturise is the most expensive mistake we see.

When to start

Start when you notice any of these: a widening parting, temple recession, more hair than usual on the pillow or in the shower (persistently above roughly 100 hairs a day), or a strong family history of pattern loss combined with early signs. You do not need to be sure. A proper assessment either reassures you or catches the loss while every option is still open.

What an assessment involves

A hair loss consultation with dermoscopic imaging is £150. We photograph and measure the scalp properly, review your history, and arrange blood tests where they add value (a targeted panel is £495). You leave with an honest written plan: what will help, what will not, and what each option costs. If PRP is right for you, a course of three sessions (£1,215) is the usual starting point, with maintenance discussed at review.

Want a straight answer about your own hair? Message us on WhatsApp: https://wa.me/447961280835?text=Hi%2C%20I%27d%20like%20to%20book%20a%20hair%20loss%20assessment.

Frequently asked questions

Can you prevent hair loss before it starts? If pattern hair loss runs in your family, an early baseline assessment is worthwhile. Treatment cannot change your genetics, but started early it can hold the line for many years.

Do hair loss shampoos work? No shampoo regrows hair on its own. Ketoconazole shampoo has modest supporting evidence as an add-on; the rest is marketing.

Is PRP better than finasteride? They work differently. Finasteride has the larger trial base; PRP has a growing one and no daily medication. Many people use both. We will tell you honestly which fits your pattern, health history and preferences.

How much does hair loss prevention cost? Assessment with dermoscopic imaging is £150. PRP is £450 per session or £1,215 for a course of three. Prescription and over-the-counter medicines are priced by pharmacies.

When is it too late? Once follicles have been dormant for years, medical treatments rarely restore them, and a transplant becomes the realistic conversation. This is why we would always rather see you early.

Ready to act while your options are open? Book your assessment on WhatsApp: https://wa.me/447961280835?text=Hi%2C%20I%27d%20like%20to%20book%20a%20hair%20loss%20assessment. Consultations are available at our Marylebone clinic, Unit 4, 10 Portman Square, London W1H 6AZ.