en Finasteride before, during and after a hair transplant
Summary
A lot of men walk into a consultation with a finasteride prescription in their pocket and one question on their mind: should I take it. Nobody can answer that for them. What a clinic can do is set out the facts the way the medicines regulators and the published literature describe them.
Finasteride is a prescription only medicine, indicated in men at an early stage of androgenetic alopecia. This article informs, it recommends nothing. A molecule that interferes with hormone balance is not ordered online, not shared between friends, and not started without a doctor who will follow you over time.
What the drug actually does to the scalp
Finasteride blocks an enzyme called 5-alpha reductase. That enzyme converts testosterone into dihydrotestosterone, better known as DHT, a derived hormone that acts directly on the follicles. In genetically sensitive men, DHT shortens the life of every hair. The follicle does not die all at once. It shrinks, produces a finer hair, then a shorter one, then nothing.
By slowing that conversion, the drug lowers DHT levels in the blood and in the scalp by roughly 60 to 70 %, depending on where the measurement is taken. That is what explains the effect on shedding. It is also what explains the side effects, because the enzyme being targeted does not only work on the head.
The hair cycle alternates a long growth phase with a resting phase that ends in shedding. Under the influence of androgens in a predisposed man, the growth phase gets shorter with every cycle. Finasteride slows that mechanism down. It does not switch it off.
One point governs everything else: finasteride protects the hair that is still alive, it does not repopulate an area that has already gone bare. A follicle that disappeared years ago will not come back because of a tablet.
What the trials measure, with the figures
Mella and colleagues pooled twelve trials and nearly 3,900 patients in a systematic review. Treated men reported an improvement in their hair more often than men on placebo, with a relative risk of 1.81 in the short-term. Hair counts rose on average by 9.4 % at twelve months and by 24.3 % at two years compared with placebo.
Those numbers describe an average, not an individual promise. Some men stabilise their density and stop there. Others see nothing at all. And the same review is a reminder of the other side of the file: the effects on sexual function.
One milligram and five milligrams are not the same medicine
The 1 mg strength, sold as Propecia and under several generic names, is aimed at male androgenetic alopecia. The 5 mg strength, better known as Proscar, targets benign prostatic enlargement, a condition that has nothing to do with hair. Diverting the prostate strength to treat baldness means multiplying by five an exposure whose individual tolerance is poorly understood. It is a bad idea, and no serious doctor suggests it.
There is also a neighbouring molecule, more potent on the enzyme. Our comparison of dutasteride and finasteride sets out how their profiles differ.
The local route, meaning a lotion applied to the scalp rather than a tablet swallowed, aims to limit how much of the product reaches the rest of the body. The published data on topical versus oral finasteride are encouraging but still thin, and the preparations on offer vary a great deal from one country to the next. This is not a risk free version of the same treatment. It is the same molecule, coming in through a different door.
In women, the rule is different
Finasteride is not indicated in female androgenetic alopecia, and one absolute contraindication frames its use: it is strictly forbidden in women who are pregnant or of childbearing age. The molecule interferes with the development of the genital organs of a male foetus.
That prohibition goes further than simply not swallowing the tablet. A pregnant woman must not handle a crushed or broken tablet either, because the active substance can pass through the skin. Intact tablets are film-coated, which is enough as long as they stay whole. A box belongs out of reach, like any other teratogenic medicine.
The side effects of finasteride
This is the part of the file that makes men hesitate, and it deserves to.
On the sexual side, the meta-analysis by Lee and colleagues brought together fifteen randomised placebo controlled trials and close to 4,500 participants. It concludes that the risk of sexual dysfunction is multiplied by 1.66 under finasteride 1 mg: erectile difficulties, reduced libido, ejaculation disorders. In the large majority of reported cases, these symptoms resolve once the treatment is stopped.
One area remains unsettled. A small subgroup of patients describes symptoms that persist after stopping, gathered under the name post-finasteride syndrome. Leliefeld and his co-authors list the mechanisms that have been proposed without being able to establish a single one with certainty. Some researchers dispute that the entity exists at all. Others document it. We are not going to settle here a debate that science has not settled. We will simply say that it exists, and that it deserves to be put on the table before the first tablet rather than after.
The psychiatric side of the question has taken up more and more room in recent years. In the United Kingdom, the MHRA introduced patient cards for finasteride from 2024, so that anyone taking the drug carries a written reminder of the warning signs. The Yellow Card scheme, which collects suspected adverse reactions, had recorded 170 reports of suicidal thoughts linked to finasteride at 1 and 5 mg between 1994 and 31 May 2025, including 19 suicides. Over the same period, dutasteride 0.5 mg accounted for five reports and no deaths. The instruction attached to those figures is short and worth memorising: if mood changes or suicidal thoughts appear, stop the treatment and seek medical advice straight away.
One last point, often forgotten in a dermatology consultation and yet decisive in a man getting older: finasteride lowers PSA levels, the blood marker used in prostate cancer screening. The trial by Andriole and colleagues, run at the prostate strength in more than 3,000 men, showed that the measured value had to be doubled to become readable again, and that on that condition the test kept all of its usefulness for detecting a cancer. The fall is less pronounced at the hair strength, but it is real. What matters fits into one sentence: your urologist needs to know that you are taking this treatment. Never leave it out of a check-up.
A medicine that cannot simply be ordered
Online platforms that ship months of treatment after a three question form are not practising medicine. They are selling. A history of depression, a plan to start a family, a prostate condition, another ongoing treatment: none of that shows up in an automated questionnaire.
Follow-up counts as much as the initial prescription. Mood, sleep, sexual function: these are reassessed at every appointment, and stopping remains possible at any moment. If you have already been operated on, our article on minoxidil and finasteride after a hair transplant sets out how these treatments fit around healing.
Around a transplant, finasteride plays a precise role
Patient information leaflets never cover this point. It is the one that comes up most often in consultation.
A transplant moves follicles taken from the donor area at the back of the head into the thinning regions. Those grafts are genetically insensitive to DHT, so they will not fall out again. The native hairs around them, though, remain vulnerable. If shedding carries on around the operated zone, the result hollows out after a few years and leaves a band of density in the middle of ground that keeps receding.
That is exactly what the trial by Leavitt and his co-authors measured. In operated men, treated for four weeks before surgery and then for a year, a visible improvement in the frontal hair was seen in 94 % of patients on finasteride against 67 % on placebo. The drug does not make the grafts grow. It protects what surrounds them.
There is a second situation, less widely known. A young patient in the middle of active shedding, with hair thinning everywhere, is not a good surgical candidate, because nobody knows where his baldness will stop. Stabilising the loss for several months before surgery changes that. A hair transplant remains the most durable treatment for androgenetic alopecia, but it is planned on calm ground. A well conducted medical treatment can turn a file that was turned down into one that can be operated.
The choice of technique, FUE or direct implantation, is discussed afterwards. Beforehand, two elements guide the decision: your stage on the Norwood-Hamilton scale and the quality of your reserve. Our medical team assesses from photographs whether you are suitable for a hair transplant.
If finasteride is not an option for you
Minoxidil remains the best documented alternative. It works differently, by extending the growth phase rather than by touching hormones, and it is used topically. Its side effect profile is different too, with scalp irritation and sometimes unwanted hair growth on the face.
Among the natural DHT blockers, saw palmetto and castor oil come up again and again. The level of evidence bears no comparison with that of regulated medicines, and nobody should expect them to halt progressive baldness. Several more recent avenues are being evaluated, described in our file on the new hair loss drugs.
In the end, two logics sit side by side. A medical treatment maintains what is still holding on, for as long as you take it. A hair transplant Turkey gives density back where there is nothing left, and that result no longer depends on a daily tablet. Many patients combine the two, and that is often the best way to let a result age properly. Talk it through with a doctor, not with a forum.
Sources
Lee, S., Lee, Y. B., Choe, S. J., et Lee, W. S. (2018). Adverse sexual effects of treatment with finasteride or dutasteride for male androgenetic alopecia: A systematic review and meta-analysis. Acta Dermato-Venereologica. https://doi.org/10.2340/00015555-3035
Mella, J. M., Perret, M. C., Manzotti, M., Catalano, H. N., et Guyatt, G. (2010). Efficacy and safety of finasteride therapy for androgenetic alopecia: A systematic review. Archives of Dermatology, 146(10), 1141-1150. https://doi.org/10.1001/archdermatol.2010.256
Leavitt, M., Perez-Meza, D., Rao, N. A., Barusco, M., Kaufman, K. D., et Ziering, C. (2005). Effects of finasteride (1 mg) on hair transplant. Dermatologic Surgery, 31(10), 1268-1276. https://doi.org/10.1111/j.1524-4725.2005.31202
Leliefeld, H. H. J., Debruyne, F. M. J., et Reisman, Y. (2023). The post-finasteride syndrome: Possible etiological mechanisms and symptoms. International Journal of Impotence Research. https://doi.org/10.1038/s41443-023-00759-5
Andriole, G. L., Guess, H. A., Epstein, J. I., Wise, H., Kadmon, D., Crawford, E. D., et al. (1998). Treatment with finasteride preserves usefulness of prostate-specific antigen in the detection of prostate cancer: Results of a randomized, double-blind, placebo-controlled clinical trial. Urology, 52(2), 195-201. https://doi.org/10.1016/s0090-4295(98)00184-8
