Finasteride: Uses in Trans Women, Trans Men and Hair Loss
Finasteride doesn't lower testosterone; it reduces conversion to DHT, so it helps hair loss in some people. It isn't a core gender-affirming hormone medicine, and it has side effects worth knowing.
Key points
- Finasteride lowers DHT, not testosterone, so it doesn't make "masculinity" disappear.
- In trans women it isn't a core medicine; if testosterone is already well suppressed it usually adds little, and it may be considered only for some people whose main concern is hair thinning.
- Side effects to know include reduced sex drive and low mood. If you have symptoms of depression, tell your doctor promptly.
Many trans women see advertising claiming that finasteride "blocks masculinity" or "helps with sex drive" and want to try it. Let's look first at how this medicine really works, because claims like that don't match the evidence, and some are actually the opposite of the truth.
How does finasteride work?
Finasteride is a 5-alpha reductase inhibitor. It blocks the enzyme that converts testosterone into dihydrotestosterone (DHT).
- DHT is a male hormone several times more potent than testosterone. It plays a major role in hair follicles (causing male-pattern hair loss), the prostate and hair growth in certain areas.
- Finasteride lowers DHT substantially but does not lower testosterone; in some people testosterone may even rise slightly.
- A similar medicine is dutasteride, which blocks the enzyme more broadly and acts for longer.
Its approved uses are male-pattern (genetic) hair loss in men and benign prostatic enlargement. Read more about DHT-related hair loss in DHT and hair loss.
- 1TestosteroneThe starting male hormone
- 25-AR enzyme5-alpha reductase converts testosterone; finasteride blocks here
- 3DHTSeveral times more potent than testosterone
- 4Effects on the bodyHair follicles (male-pattern hair loss), prostate, some body hair
Finasteride lowers DHT a lot but does not lower testosterone levels.
How much does it help trans women?
On feminising hormone therapy, testosterone is already suppressed, so DHT falls too. If testosterone is in the target range (below 50 ng/dL), adding finasteride usually gives little extra benefit.
The WPATH SOC-8 guidelines (2022) state that evidence for this class of medicine in feminising hormone therapy is still limited, so it isn't recommended routinely. It may be considered in specific situations, such as:
- Male-pattern hair loss continuing even when hormones are well controlled
- People who can't use anti-androgens fully and whose main concern is hair thinning
What finasteride does not do: it doesn't enlarge breasts, reduce muscle or change the voice. The claim that it "fixes loss of sex drive" is wrong, because this medicine can actually reduce sex drive.
See the main hormone regimens in trans women's hormone regimens.
May be considered in some cases
- Male-pattern hair loss continues despite good hormone control
- Blockers can't be used fully and hair thinning is the main concern
What the drug doesn't do
- Doesn't grow breasts
- Doesn't reduce muscle or change the voice
- Doesn't fix low desire; may even lower it
WPATH SOC-8 (2022) does not recommend it routinely because evidence is limited.
Can trans men use it?
Some trans men on testosterone experience rapid male-pattern hair loss. If this worries you, you can talk to your doctor about a DHT-lowering medicine, but be aware that DHT contributes to clitoral growth (the enlargement caused by testosterone) and to hair in certain areas. The medicine may reduce these changes, especially if started early in hormone therapy.
Many people therefore choose to wait until the changes they want have happened before considering it, or choose topical minoxidil, which doesn't affect hormones (see more about testosterone in trans men in masculinising hormone therapy).
Side effects to know
- Reduced sex drive, fewer or weaker erections and less ejaculate (in people who still have testes)
- Breast tenderness or swelling
- Low mood and anxiety. The US Food and Drug Administration (FDA) has added warnings about depression and suicidal thoughts to the drug label.
- A post-finasteride syndrome has been reported in a small number of people after stopping; the evidence is still debated.
- The medicine affects male fetuses, so anyone who could be pregnant should not handle broken tablets.
- It lowers PSA by about half, so if you have prostate testing, tell your doctor you're taking it.
How to use it safely
Finasteride needs a doctor's assessment first, because whether it suits you depends on your goals, hormone levels and mental health history. Your doctor will weigh whether you will really benefit against the possible side effects. Don't buy it and use it yourself because of advertising.
Other options for hair loss include topical minoxidil or low-dose oral minoxidil (as prescribed by a doctor), laser treatment or hair transplantation. For acne and oily skin from hormones, read hormonal acne.
Consultations at Dr. Kris Clinic
At Dr. Kris Clinic, I help assess whether you need a DHT-lowering medicine, check your hormone levels before deciding and monitor both physical and emotional side effects, for trans women, trans men and men with hair loss. Consultations are available in Surat Thani and online, in English if you prefer. For an overview of hormone care, read gender-affirming hormone therapy (GAHT).
Medicines and services your doctor may consider
Prices are per pack. Every medicine is prescribed only after a doctor's assessment; your doctor will advise whether it suits you. See all medicines & services
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Assessment, blood tests and follow-up with a judgement-free doctor, in line with WPATH SOC-8.
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Frequently asked questions
Does finasteride make trans women look more feminine?
Only to a limited extent. If testosterone is already suppressed to target, the extra benefit is usually small. It doesn't enlarge breasts or change body shape, though it may help hair thinning in some people.
Does finasteride increase sex drive?
No. On the contrary, reduced sex drive is a known side effect.
Can trans men take finasteride to prevent hair loss?
It may help, but it can reduce some desired changes, such as clitoral growth and hair in certain areas. Talk with your doctor about the right timing.
อ่านบทความนี้เป็นภาษาไทย
Finasteride คืออะไร ใช้ในสาวทรานส์ ทรานส์แมน และผมร่วงอย่างไร →
References
- Coleman E, et al. Standards of Care for the Health of Transgender and Gender Diverse People, Version 8. Int J Transgend Health. 2022;23(Suppl 1):S1–S259.
- Hembree WC, et al. Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2017;102(11):3869–3903.
- U.S. Food and Drug Administration. Propecia (finasteride) prescribing information, revised labeling including depression and suicidal ideation warnings. 2022.
- Irwig MS. Finasteride and suicide: a postmarketing case series. Dermatology. 2020.
This article is for education and does not replace diagnosis or treatment by a doctor. If you have symptoms or concerns, please see a doctor.
