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The Definitive Guide to Dutasteride
Dutasteride is a prescription medicine and one of the most potent treatments for androgenetic hair loss. It is a close relative of and works in much the same way, but it suppresses DHT more completely. started out as a medication. Unlike finasteride, it is not licensed for hair loss anywhere in the UK. Despite this, it has uses off-label as a tablet and in topical compounded treatments when finasteride has not been enough. This guide explains how dutasteride works and how it compares to finasteride. We review who it is suitable for, the differences between the oral and topical forms, what results to expect and its side effects. Discover the latest regulatory position and how to get it in the UK for hair loss.
What is Dutasteride?
Dutasteride is a 5 inhibitor. It got approval by the FDA in 2002 as a 0.5mg capsule (Avodart) to treat enlarged prostates. It has never been licensed for hair loss in the UK or the US. However, oral dutasteride 0.5mg has .
Like finasteride, dutasteride works by blocking 5-alpha-reductase. This is the enzyme that converts testosterone into , the hormone behind genetic hair loss. We explain this process, and how rising DHT drives , in our . The key difference is that there are two forms of the enzyme, type I and type II. Finasteride blocks only type II. Dutasteride blocks both, and it is more potent at each. This is why it suppresses DHT more completely. At the 0.5mg daily dose, dutasteride lowers serum DHT by , compared with around 70% for finasteride at 1mg.
What’s the Difference Between Dutasteride vs Finasteride?
Generally speaking, dutasteride is the more potent of the two. That extra potency is its headline advantage, but it is not the only difference, and it is not always an advantage. The practical differences between include:
Despite being more potent, dutasteride is not the default choice. Finasteride is first-OnabotulinumtoxinAAbobotulinumtoxinAIncobotulinumtoxinAPrabotulinumtoxinALetibotulinumtoxinARimabotulinumtoxinBHyaluronic Acid FillersCalcium Hydroxylapatite Acid FillersPolymethylmethacrylate FillersAutologous Fat Lines TreatmentGlabellar Frown Lines TreatmentCrow’s Feet TreatmentBunny Lines Brow LiftLip FlipGummy Smile CorrectionMasseter ReductionJaw SlimmingDimpled Chin SmoothingCobblestone Chin SmoothingNefertiti Neck LiftMicro-BotoxMesotoxHyperhidrosis TreatmentChronic ReliefBruxism TreatmentTMJ TreatmentCervical Dystonia TreatmentNeck Spasm TreatmentBlepharospasm TreatmentLip AugmentationLip EnhancementTear Trough FillersNasolabial Fold SofteningMarionette Line FillersLiquid RhinoplastyNon-Surgical Nose JobJawline DefinitionChin AugmentationTemple VolumisingHand RejuvenationAcne Scar Subcision Filling (dongfang-wisdom.com) as it has the longest safety record and is enough for most men. Dutasteride is usually reserved for when finasteride has not done enough or has stopped working.
Is Dutasteride Available for Hair Loss in the UK?
Dutasteride is licensed in the UK under the brand name Avodart, and as versions, but only to treat an enlarged prostate. It has no UK licence for hair loss. This is a key difference from finasteride, which is licensed for male pattern hair loss at 1mg.
This means that any dutasteride prescribed for hair loss is used outside its licence. There are two ways this is done. The oral capsule is prescribed off-label, meaning a licensed medicine used for an unapproved purpose. The topical form is an unlicensed special, compounded by a pharmacy to order. Both are legal and routine in UK medical practice. If you’re interested, we explain the distinction in our guide to .
Not having formal approval for hair loss does not make dutasteride unsafe. However, it does mean it should be prescribed by a doctor or medical prescriber after assessment of your suitability and will monitor you. This is a prescription only medicine with some potentially serious side effects so you should never use it without proper medical supervision.
What Doses & Concentrations are Used in Hair Loss?
Dosing depends on the form, as well as on dutasteride’s unusually long half-life, which sets it apart from finasteride. Where clears the body in hours, dutasteride lingers for weeks and this shapes dosing of both the oral and topical forms. Your prescriber will set the right dose and frequency for you, but the general approach for each form is:
What Results Can You Expect from Dutasteride?
Dutasteride is one of the most hair loss treatments available. That said, the same realistic expectations apply to both, because they work in the same way. Dutasteride protects the hair you have first, and regrows some of what you have lost second. The main things to keep in mind are:
Is Dutasteride Safe for Hair Loss?
Like finasteride, dutasteride is effective and with appropriate use, mostly safe. It shares the same side effects as finasteride, both work by suppressing DHT. The most serious of these come down to how much DHT suppression occurs throughout the body. If anything, dutasteride’s more DHT suppression and its long half-life mean these effects warrant even more caution. The potential side effects of dutasteride include:
These side effects can occur with any form of dutasteride. In theory, however, they are less likely with the topical form, because far less of the drug reaches the bloodstream. can also cause local side effects where you apply it such as scalp irritation, itching and dryness. These are usually mild and settle as the skin adjusts. There is one important caveat that sets dutasteride apart from finasteride. Its very long half-life means that any side effects, if they do occur, can take considerably longer to settle after stopping, because the drug remains in the body for weeks.
The regulatory position reflects this caution. In 2024, the MHRA introduced patient alert cards and strengthened warnings for finasteride. In 2025, following a , it gave a precautionary warning to dutasteride too, noting reports of mood alterations including depression and suicidal thoughts were also possible. Anyone taking dutasteride who develops depression or suicidal thoughts should consult their doctor as soon as possible. The same is also true for sexual side effects. This is one of the reasons dutasteride is a prescription-only that needs proper medical .
What Other Treatments Work Best with Dutasteride?
Whilst dutasteride blocks the hormone that drives pattern hair loss, but it does not stimulate growth directly. This is why it works best alongside treatments that act through other mechanisms, so their benefits add up rather than overlap. The actives most often combined with dutasteride are:
Because dutasteride’s benefits depend on continued use, stopping means your hair loss will gradually return. Thanks to its long half-life this happens more slowly than with finasteride, but it still happens over the months that follow. If you are considering stopping, for side effects or any other reason, make it an informed decision and discuss it with your clinician first. Our posts on and cover these options in detail.
Who Can & Cannot Use Dutasteride?
Dutasteride is more potent than finasteride and has no licence for hair loss. This means patient selection matters even more. People who should avoid it, or use it only with caution, include:
As with any hair loss treatment, it is worth confirming the cause of your hair loss first. Dutasteride only helps DHT-driven loss, so it does for shedding caused by , thyroid problems or a , which need treating in their own right.
How to Get Dutasteride in the UK
Dutasteride is prescription-only in every form, so you cannot buy it over the counter. it is not licensed for hair loss, it is only available off-label or as an unlicensed compounded treatment. It always and monitoring by a doctor or provider who deems it for you. It is not available on the NHS for hair loss. Checkout our review of how to access if it is appropriate for you.
At City Skin Clinic, we believe hair loss treatment should be . We compounded hair loss treatments containing topical and other actives where appropriate. After an online consultation, one of our doctors will design a bespoke treatment plan for you. Read more about our and . with one of our doctors today and take the first step towards regrowing your hair.
This article is for general information and does not constitute medical advice. Dutasteride is a prescription-only medicine and you should only use it under the supervision of a medical prescriber. Always read the patient information leaflet and report any suspected side effects to the MHRA via the Yellow Card scheme.
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