Hair Loss Treatments: What the Research Really Shows

For hereditary hair loss, the best-studied treatments are topical minoxidil and, in men, finasteride. Both are backed by many randomised trials and meta-analyses ^[2,5]. Dutasteride and oral minoxidil also have good evidence but are used off-label in Switzerland. PRP, microneedling and laser devices show benefits in studies of lower quality, while most supplements are poorly supported. For severe alopecia areata, JAK inhibitors have high-certainty evidence ^[20].

In short: Start with treatments that have strong evidence: minoxidil and, for men, finasteride. Add-ons such as PRP or microneedling may help, but the evidence is weaker. Be sceptical of products backed only by small or company-funded studies, and get a diagnosis first, because the right treatment depends on the type of hair loss.

This overview summarises the evidence for the main treatments. Each section links to a detailed guide. It covers mainly androgenetic alopecia (pattern hair loss), the most common type; read about other causes in our guide to hair loss.

How we rate the evidence

Not all studies are equal. We use a simple four-level scale based on the type and quality of the studies available:

Level	Meaning	Typical sources
High	Several large, well-designed randomised trials with consistent results	Meta-analyses of RCTs, Cochrane reviews with high-certainty ratings
Moderate	Randomised trials exist but are few, small, short or inconsistent	Single RCTs, meta-analyses of small trials
Low	Mostly small trials with high risk of bias, or observational data	Pilot RCTs, case series, retrospective studies
Very low	Expert opinion, lab studies or anecdotes	Reviews without systematic methods, marketing claims

This mirrors the GRADE approach used by Cochrane and guideline groups such as the European S3 guideline on androgenetic alopecia ^[1]. A network meta-analysis ranks many treatments together by combining direct and indirect comparisons ^[2,3]. That is useful when head-to-head trials are rare, but less reliable than direct comparisons. Our editorial policy explains how we select sources.

The evidence at a glance

Treatment	Evidence level	What studies show	Source
Topical minoxidil (men)	High	Superior to placebo in meta-analyses; evidence comparing 2% and 5% rated high quality	[3,5]
Topical minoxidil (women)	Moderate	About twice as many women report moderate to marked regrowth vs placebo; 2% and 5% similar	[6]
Oral minoxidil (low dose)	Moderate	Similar density to topical in 4 RCTs; more facial and body hair	[7,8]
Finasteride 1 mg (men)	High	Superior to placebo; largest gain in terminal hairs at 48 weeks in a network meta-analysis	[2,5]
Finasteride (women)	Low	No better than placebo in Cochrane analysis (low-quality evidence)	[6]
Topical finasteride	Moderate	Better than placebo in a phase III trial; much lower blood levels	[13]
Dutasteride 0.5 mg	Moderate	Beat finasteride in a 917-man RCT; ranked most effective in network meta-analyses	[4,10]
PRP	Low to moderate	Increases density and thickness vs placebo; protocols vary	[14,15]
Microneedling (combined)	Low to moderate	Combined with drugs, better than either alone in 13 RCTs	[16]
Low-level laser (LLLT)	Low to moderate	Increases hair density vs sham; high heterogeneity	[5,17]
JAK inhibitors (alopecia areata)	High	30–40% regain most scalp hair in phase 3 trials	[18,19,20]
Hair transplant	Low to moderate	Graft survival about 85–93% in observational studies	[21]
Supplements (no deficiency)	Low	Potential benefit for some products; study quality varies, larger RCTs needed	[22]

Minoxidil: topical and oral

Topical minoxidil is one of only a few hair loss treatments recognised by regulators. A meta-analysis of good- and fair-quality RCTs found both 2% and 5% minoxidil superior to placebo in men, and 2% superior in women ^[5]. In a Cochrane review for women, minoxidil roughly doubled the chance of moderate to marked regrowth. There was no clear difference between 2% and 5% ^[6]. A network meta-analysis rated the evidence comparing minoxidil 2% and 5% as high quality, and 5% versus placebo as moderate ^[3].

Oral minoxidil at low doses is increasingly popular. A meta-analysis of four randomised trials found no difference in hair density compared with topical minoxidil, but hypertrichosis (unwanted hair) was about twice as frequent ^[7]. In a double-blind trial in men, 5 mg oral minoxidil was not superior to topical treatment overall ^[8]. A study of 1,404 patients found that only 1.7% stopped because of side effects ^[9].

More detail: minoxidil guide and oral minoxidil evidence review.

Finasteride and dutasteride

These tablets block the enzyme that converts testosterone into DHT, the hormone that shrinks hair follicles in pattern hair loss.

• Finasteride 1 mg: superior to placebo in meta-analyses ^[5]. In a network meta-analysis, it gave the greatest increase in terminal hair count at 48 weeks ^[2].
• Dutasteride 0.5 mg: blocks both forms of the enzyme. In an RCT of 917 men, it increased hair count and hair width more than finasteride at 24 weeks, with similar side effects ^[10]. Network meta-analyses rank it the most effective monotherapy ^[4]. It is not licensed for hair loss in Switzerland.
• Topical finasteride: a phase III trial of 458 men showed significantly more hair than placebo. Blood levels of finasteride were more than 100 times lower than with tablets ^[13].
• In women: the Cochrane review found finasteride 1 mg no more effective than placebo, based on low-quality evidence ^[6].

Side effects: in a meta-analysis of 15 placebo-controlled trials, finasteride 1 mg increased the risk of sexual dysfunction by about 1.7 times ^[11]. In 2025 the EMA confirmed suicidal thoughts as a side effect of finasteride tablets, with unknown frequency ^[12].

More detail: finasteride guide and post-finasteride syndrome evidence review.

PRP (platelet-rich plasma)

PRP uses a concentrate of your own blood platelets, injected into the scalp. Two meta-analyses of randomised trials found that PRP increased hair density and thickness compared with placebo, with only temporary minor side effects ^[14,15]. However, preparation methods, number of sessions and injection intervals vary widely between studies. An earlier network meta-analysis rated the quality of evidence for PRP versus placebo as very low ^[3]. PRP is best viewed as an add-on. See our PRP guide.

Microneedling

Microneedling creates tiny controlled injuries in the scalp, which may stimulate growth and improve drug absorption. A meta-analysis of 13 RCTs with 696 patients found that microneedling combined with a drug such as minoxidil improved hair density and diameter more than either treatment alone, without more side effects ^[16]. Evidence for microneedling on its own is limited, and a 2024 network meta-analysis found it less effective than the oral 5-alpha reductase inhibitors ^[4].

Low-level laser therapy (LLLT)

Laser caps, helmets and combs use red light. A meta-analysis of 38 studies found a significant increase in hair density compared with placebo after 4 to 26 weeks, but with high heterogeneity between studies ^[17]. An earlier meta-analysis also found LLLT superior to placebo in men ^[5]. In women, the Cochrane review found inconsistent results for laser combs ^[6].

JAK inhibitors for alopecia areata

Alopecia areata is an autoimmune condition, different from pattern hair loss. Here the evidence is unusually strong. In two phase 3 trials with 1,200 adults with severe disease, 36 to 39% on baricitinib 4 mg regrew at least 80% of their scalp hair at 36 weeks, compared with 3 to 6% on placebo ^[18]. Ritlecitinib showed similar results in patients aged 12 and older ^[19]. A Cochrane review rated the baricitinib evidence as high-certainty and the evidence for most other alopecia areata treatments as very uncertain ^[20].

More detail: JAK inhibitors for alopecia areata.

Hair transplant: graft survival

A hair transplant is not a medicine, but its success can be measured. A meta-analysis found pooled graft survival of about 85 to 93% and satisfaction of 90 to 97% in non-scarring hair loss ^[21]. The data are mostly from observational, single-centre studies. Results depend heavily on the surgical team.

More detail: hair transplant success rate and our hair transplant guide.

Vitamins and supplements

A JAMA Dermatology systematic review looked at 30 studies of supplements in people without a known deficiency. Some products showed potential benefit, and side effects were rare and mild. However, quality varied, no diet-based studies qualified, and the authors called for larger trials with active comparators ^[22]. If you have a confirmed deficiency, such as low iron, correcting it is sensible. Supplements should not replace proven treatments.

How to read a hair loss claim

Advertising for hair loss products often quotes studies. A few questions help separate solid evidence from marketing:

• Was there a control group? Hair naturally fluctuates with the seasons, and many people improve simply by starting to look after their hair. Without a placebo or comparison group, a "70% improvement" means little.
• How many people, for how long? A trial of 30 people over 12 weeks cannot show a lasting effect on a condition that progresses over decades.
• What was measured? "Hair count per cm²" in a marked area, assessed by a blinded investigator, is more reliable than a questionnaire filled in by participants who know what they took.
• Who paid? Manufacturer funding doesn't make a study wrong, but independent replication matters.
• Who was studied? Results in young men with early hair loss may not apply to women or to advanced baldness.

Meta-analyses and Cochrane reviews answer most of these questions for you, which is why this overview relies on them wherever possible.

How strong is the evidence overall?

Across hair loss research, some common weaknesses recur:

• Short trials: most RCTs last 24 to 48 weeks, while hair loss is lifelong.
• Different outcome measures: hair counts, photo ratings and patient questionnaires are not comparable, which complicates meta-analyses ^[2,3].
• Industry funding is common, especially for drugs and devices.
• Few head-to-head trials: rankings rely heavily on indirect comparisons ^[2,3,4].
• Women are under-studied: the Cochrane review found only five of 47 trials at low risk of bias ^[6].
• Side effects may be under-reported, as discussed for finasteride ^[11,12].

The European S3 guideline remains the main European reference ^[1], but it predates much of the newer research on oral minoxidil, dutasteride and JAK inhibitors.

What this means for you

1. Get a diagnosis. A dermatologist can distinguish pattern hair loss from alopecia areata, telogen effluvium and other causes. Women should read our guide to hair loss in women.
2. Start with the strongest evidence: minoxidil and, for men, finasteride or an alternative discussed with your doctor.
3. Give it time: judge results after 6 to 12 months.
4. Consider add-ons such as PRP or microneedling if you want more, knowing the evidence is weaker.
5. If areas are already bald, medication will not refill them. Check your stage on the hair loss scale and see what a transplant would cost.