Key points
- ◆Topical application of finasteride to the scalp, aiming to reduce local DHT.
- ◆Seeks lower systemic exposure than oral finasteride.
- ◆Usual formulation is a 0.25% solution, alone or combined with minoxidil.
- ◆Off-label use; evidence is more recent than for the oral route.
- ◆Retains the pregnancy contraindication as a precaution.
Description
Topical finasteride is a formulation of finasteride designed to be applied directly to the scalp. Its aim is to reduce dihydrotestosterone (DHT) locally, limiting the systemic exposure seen with the oral route. It is used off-label for androgenetic alopecia.
Indications
- Androgenetic alopecia (off-label use), especially in patients who wish to minimise systemic exposure.
- Often formulated combined with topical minoxidil.
Mechanism of action
As with oral finasteride, it inhibits the 5-alpha-reductase enzyme and reduces DHT, the main driver of follicular miniaturisation. Applied to the skin, it aims to act preferentially on the scalp, although part of the drug can be absorbed and also reduce blood DHT.
Mechanism of action
Inhibiting 5-α-reductase lowers DHT and slows follicle miniaturisation.
Usual dosage
The most studied concentration is the 0.25% solution, applied to the scalp once or twice daily depending on the formulation. As with the oral route, results require several months of continuous use and depend on maintaining treatment.
Side effects
It is generally well tolerated locally. The following may occur:
- Irritation, itching or redness at the application site.
- Systemic effects similar to the oral route (including sexual effects), in principle less likely but possible due to partial absorption.
Contraindications
- Pregnant women or women of childbearing age without contraception.
- Hypersensitivity to the active substance.
- Paediatric population.
Pregnancy and breastfeeding
As a precaution, topical finasteride retains the contraindication in pregnancy. Pregnant women or those who may be should avoid both its use and contact with the application area. It is not advised during breastfeeding.
Important interactions
Being finasteride, it shares the considerations of the oral route, in particular a possible reduction in PSA if there is relevant systemic absorption. Local interactions with other hair products depend on the formulation.
Level of scientific evidence
Level of evidence: moderate and growing. Some trials have shown efficacy comparable to the oral route with a smaller fall in serum DHT, but long-term experience is more limited. Its use is off-label and formulations may vary.
Frequently asked questions
Does it have fewer side effects than finasteride tablets?
The aim is to reduce systemic exposure and, with it, side effects, but part of the drug can be absorbed, so these are not entirely ruled out.
Can it be used with minoxidil?
Yes. In fact, it is very often formulated combined with topical minoxidil to add their effects.
Can women use it?
Only in selected cases and under medical supervision. It is contraindicated in pregnant women and women of childbearing age without contraception, who must also avoid contact with the treated area.
How long does it take to work?
Like oral finasteride, it requires several months of continuous use to see results.
References
- Piraccini BM, et al. Efficacy and safety of topical finasteride in male androgenetic alopecia: a randomized controlled trial. J Eur Acad Dermatol Venereol (EADV). 2022.
- Caserini M, et al. Pharmacokinetics of topical finasteride. Int J Clin Pharmacol Ther.
- Lee SW, et al. A systematic review of topical finasteride in androgenetic alopecia. J Drugs Dermatol.
- Kanti V, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia. J Eur Acad Dermatol Venereol (EADV). 2018. doi:10.1111/jdv.14624.
Clínica Valorian's view
At Clínica Valorian we consider topical finasteride an interesting alternative for patients who wish to reduce systemic exposure, usually combined with minoxidil and always on an individual basis.
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This fact sheet is for information and medical education purposes only. It does not replace a medical consultation or an individual prescription.