Do hair loss treatments actually work? What BBC Radio 4's Best thing since Sliced Bread says

In December 2024, BBC Radio 4's consumer science programme Sliced Bread asked a simple question: with so many lotions and pills advertised online, do any of them actually stop hair loss or grow it back? Presenter Greg Foot put the question to Professor Ralf Paus of the Miller School of Medicine at the University of Miami, one of the most cited researchers in the field, and went through the studies with him.

This is a summary of what the programme found. The original article is here: Do hair loss treatments actually work? (BBC Radio 4), and you can listen to the full episode on BBC Sounds.

Four causes of hair loss

Professor Ralf Paus of Miami University groups hair loss into four broad causes:

Hormonal
An imbalance that makes follicles smaller or stops them growing. This is the mechanism behind both male and female pattern hair loss.

Inflammatory
The immune system attacks the follicle, as in alopecia areata. See our article on inflammation.

Toxic
Something damages the follicle directly. Chemotherapy is the best known example.

Drug-induced
Some medications cause shedding as a side effect.

Female pattern hair loss and oestrogen

In women the picture is a combination of androgen activity and a relative shortage of oestrogen. That is why shedding is common after giving birth, when the very high oestrogen levels of pregnancy fall sharply, and again through the menopause as levels decline more slowly.

When Paus ran hair clinics in Germany he often prescribed a topical oestrogen tincture. His observation was that it did not grow new hair, but it kept follicles in their growth phase for longer. The programme is careful to note that this is not available on the NHS, is not in the official guidance, and does not yet have consistent trial evidence behind it.

Male pattern hair loss is set before birth

Male pattern hair loss comes down to androgens. Testosterone is a weak androgen, but over time it is converted into the much more potent dihydrotestosterone (DHT). When follicles on the top of the head are exposed to DHT they produce molecules that shut hair growth down. Beard follicles do the exact opposite with the same hormone and grow more. As Paus puts it, the way follicles in different regions respond to the same hormone is "completely different", and that response is programmed during foetal development.

Finasteride: a pill that blocks DHT

Finasteride blocks the enzyme that converts testosterone into DHT. Paus calls it "a very useful technique for inhibiting the progression of male pattern baldness". One large clinical study found it stopped hair loss in 80 to 90% of men.

Points the programme raises:

• It is only licensed for men, because of the risk of side effects in women, especially during pregnancy. Paus suggests it may be justified in post-menopausal women, but that is a decision for a prescriber.
• Some men report sexual dysfunction and mental health problems. In 2024 the MHRA added a patient card to UK packs to make sure people are aware of these.
• Dutasteride appears "slightly superior" in smaller trials, but it is unlicensed for hair loss, so Paus advises medical supervision.

Minoxidil: a blood pressure drug that grows hair in some people

Minoxidil is the active ingredient in products such as Regaine. It was developed to treat high blood pressure and hair growth was a side effect. Paus is honest that "what minoxidil actually does to our hair follicles is still not clear enough".

The numbers he gives are worth writing down:

• More than half of people who apply it twice a day for at least six months see their hair loss stop progressing.
• The share who see regrowth they would call cosmetically acceptable is "much lower".
• The response is unpredictable. You might be one of the few who sees a dramatic effect, or you might see nothing.

Oral minoxidil tablets are sold by online pharmacies and can also work, but they carry slightly higher risks, including cardiac arrhythmia. Paus is clear that anyone with heart problems should only use the topical form.

Give it a year, and keep going

The single biggest mistake Paus sees is people giving up too early. Studies show you can still become a responder to minoxidil after six months, so his advice is to try it for at least a year. Finasteride takes even longer: "Don't even start it if you're not willing to take it a year."

He also says it "definitely makes sense" to combine the two: finasteride tablets with topical minoxidil.

The catch, and the programme stresses this, is that both only work for as long as you take them. The underlying cause of the hair loss has not gone away, so stopping means the gains go too.

Caffeine

Laboratory studies show caffeine stimulates hair follicles and makes them more stress resistant, but clinical evidence in people is still missing. Whatever the ingredient, Paus says no shampoo will give you a predictable hair growth effect, because the contact time with the scalp is far too short. Anything that is going to do something needs to stay on the skin and sink in, which means an alcohol-based tincture rather than a rinse-off product.

Supplements: eat the steak

Follicles are built to take amino acids and other nutrients from the blood, so the right supplement can at least in principle have an effect. The programme's verdicts:

Biotin (vitamin B7)
Good for nails, but "not very good evidence" that it does much for hair shaft production.

Vitamin D
Useful for many reasons, but hair growth is not high on the list.

Collagen
It is a protein, and you do need enough protein, but there is no good evidence that collagen on its own promotes hair growth. In Paus's words, "you might as well eat a good steak", or nuts and soy if you are vegetarian. See our notes on protein powder.

The bottom line

The licensed drugs, finasteride and minoxidil, "are definitely not marketing BS", but if they work for you, you will need to keep taking them indefinitely. Plenty of cosmetic products and supplements have laboratory evidence that an ingredient could help. What is largely missing is the clinical evidence that would let you make an informed decision.

That gap is the reason this library exists, and it is the reason our own approach starts from a DNA test and a prescriber review rather than from a product on a shelf.

Sources

• Do hair loss treatments actually work? BBC Radio 4, Sliced Bread (article, correct at time of broadcast on 5 December 2024)
• Sliced Bread: Hair Loss Products (episode on BBC Sounds)

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