Medication questions Finasteride
Topical vs oral finasteride: what is the difference?
Short answer
Oral finasteride 1 mg is a licensed UK tablet for male pattern hair loss. Topical finasteride has no UK licence and is supplied as an unlicensed special, made up to a prescription. A published trial found much lower blood levels of finasteride with a topical spray, but lower is not zero, so the MHRA warnings still apply.
Key facts
- Oral finasteride 1 mg: licensed in the UK for male pattern hair loss.
- Topical finasteride: no UK licence; supplied as an unlicensed special.
- In one trial, a 0.25% spray gave blood finasteride levels over 100 times lower than the tablet, and smaller falls in blood DHT.
- UK donor guidelines accept donors who have used only topical finasteride.
Licensing: the biggest practical difference
Finasteride 1 mg tablets, sold as Propecia and as generics, are licensed by the MHRA for male pattern hair loss in men. Every finasteride product listed on the UK electronic medicines compendium (eMC) is a tablet.
Topical finasteride, applied to the scalp as a liquid or spray, does not have a UK licence. When it is prescribed in the UK, it is usually made by a specialist pharmacy as an unlicensed special, a medicine prepared to order for an individual patient. Our glossary explains what compounded means and what off-label means.
At WMG Meds, topical finasteride is available only as a compounded combination with minoxidil and azelaic acid, at finasteride strengths of 0.2% or 0.04%. It is an unlicensed special, prescribed after an individual assessment.
How much reaches the bloodstream
The main published trial comparing the two is a randomised study of 458 men published in the Journal of the European Academy of Dermatology and Venereology (Piraccini and colleagues). It compared a 0.25% topical finasteride spray, finasteride 1 mg tablets and placebo over 24 weeks.
On exposure, it reported that maximum blood levels of finasteride were more than 100 times lower with the spray. Blood DHT fell by 34.6% with the spray and by 55.6% with the tablet. So topical finasteride still reaches the bloodstream and still lowers DHT, to a lesser extent in that study.
Two cautions. These figures describe that 0.25% spray, not every topical formulation, and lower strengths would be expected to give lower exposure still. And this page deliberately does not compare how well the two work: that depends on the person and is a question for a prescriber.
How each is used
Tablets are taken once a day, with or without food, swallowed whole. Crushed or broken tablets should not be handled by women who are or may be pregnant.
Topical solutions are applied to the scalp as directed on the label. Local effects such as scalp irritation and dryness are the most common problems, often linked to the propylene glycol in the liquid. A woman who is or may become pregnant should not handle the solution or apply it for you, because finasteride can be absorbed through the skin.
Blood donation differs too. UK donor guidelines defer donors for 4 weeks after finasteride tablets, but say a donor who has only used topical finasteride can be accepted. See finasteride and blood donation.
Safety warnings apply to both
The MHRA's Drug Safety Updates of 29 April 2024 and 11 May 2026 warn that finasteride is associated with low mood, depression, suicidal thoughts and sexual side effects that may persist after stopping. The updates do not mention topical finasteride specifically. Because topical finasteride still reaches the bloodstream, WMG Meds applies the same precautions to it, including asking about mental health history and reviewing for side effects. See our MHRA safety updates page.
Whether a tablet, a topical or neither suits you is an individual clinical decision. The free online assessment is a good place to raise your preferences and any concerns.
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Start your free assessment →Related questions
Is topical finasteride licensed in the UK?
No. The finasteride products listed on the UK eMC are all tablets. Topical finasteride is prescribed as an unlicensed special, made to order by a pharmacy, and the prescriber should explain that before you start.
Does topical finasteride have side effects?
Yes. Scalp irritation and dryness are the most common. Because some finasteride reaches the bloodstream, the mood and sexual side effects covered by the MHRA warnings remain possible, and WMG Meds applies the same precautions as for tablets.
Can a pregnant partner touch topical finasteride?
No. A woman who is or may become pregnant should not handle the solution or apply it for you, because finasteride can be absorbed through the skin and could affect the development of a male baby.
Can I switch from tablets to a topical?
It is possible, but it is a prescribing decision. Talk to your prescriber about why you want to switch, for example a side effect, so they can consider the options, including what happens to your hair during any change.
Can I give blood if I use topical finasteride?
UK donor guidelines say a donor who has only used topical finasteride, such as a spray, foam or lotion, can be accepted. If you also take finasteride tablets, the 4-week deferral applies. Tell the donor service what you use.
Sources
- Piraccini BM et al. Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial. JEADV 2022
- Propecia 1 mg: summary of product characteristics (eMC, revised 29 June 2026)
- JPAC, Guidelines for the UK Blood Transfusion Services: Alopecia (whole blood, August 2026)
- MHRA Drug Safety Update, 11 May 2026: Finasteride and dutasteride, updated safety warnings
Facts checked against these sources on 4 October 2026. This page is general information, not personal medical advice. Read our editorial policy.