Overview

Cross-sex hormones are the most common medical step in gender transition and, for many people, the only one. They are usually prescribed long term, often for life. They do not change a person's sex. They create a hormonal state the body did not develop in: male-range testosterone in a female body, or female-range estrogen with suppressed testosterone in a male body. The visible changes are only part of the story. The same hormones also act on the heart, blood, bones, liver, brain, genitals and reproductive organs.

Neither testosterone nor estrogen was developed or licensed for this purpose. In the United States, for example, testosterone products are approved by the FDA only for males with a deficiency of their own testosterone (Medical Letter 2025), so their use in females is off-label. Much of what is known about safety comes from hormone use in other groups, such as men with low testosterone and menopausal women, plus observational studies of trans patients.

This hub summarises the six detailed pages in this section:

For adolescents, hormones often follow puberty blockers. Some people take hormones without a prescription; see DIY hormones. Both are introduced, with their main risks, in the section on blockers and DIY hormones further down.

How hormones are prescribed

There are two broad routes to a prescription. They differ mainly in how much assessment happens first.

• Assessment ("gatekeeping") model: a specialist clinic assesses the person, often over several appointments, before recommending hormones. Clinicians look at the history of gender distress, mental health, trauma and other possible explanations. UK adult gender clinics have traditionally worked like this. Critics in trans communities call it gatekeeping because of long waits and the power it gives clinicians.
• Informed consent model: the person is told about the effects and risks, signs a consent form, and can get a prescription without a mental health assessment or referral. Many US Planned Parenthood clinics use this model and say patients can often be prescribed hormones at the first visit, with no letter from a mental health provider required (Planned Parenthood Columbia Willamette; Planned Parenthood North Central States).

Detransitioners who went through informed consent clinics often describe how quick it was. Several describe appointments of under an hour.

being freshly 18 walking into that clinic and being given a prescription for male steroids within the span of less than 30 mins after only 3-5 questions is grounds for a medical malpractice lawsuit. —Ok_Cucumber_2106, detrans female

They literally diagnosed me with gender dysphoria and told me what the treatment was for it. Then I "consented" to the treatment... that they told me was the treatment. —brightescala, detrans female

The second quote points to a deeper problem than speed. Consent is only "informed" if the person understands the risks, the uncertainty, and the other possible explanations for their distress. In Littman's survey of 100 detransitioners, 55% felt the evaluation they received before transition was inadequate. A UK case-note review of 175 adults discharged from a gender clinic (Hall et al. 2021) found that neurodevelopmental conditions, adverse childhood experiences and ongoing mental health problems were linked to worse outcomes. Those are exactly the factors a quick appointment can miss. For the full argument, see informed consent critique.

At a glance: testosterone vs estrogen

The two treatments are often described together, but they do very different things to very different bodies. The key difference is that testosterone causes several permanent changes early, while estrogen in an adult male mostly causes changes that fade after stopping, with breast tissue and fertility the main exceptions.

This asymmetry matters. Females often stop testosterone after its permanent effects have already happened, because voice and hair change in the first months. Males who stop estrogen often recover more of their original body, but some report sexual dysfunction and low testosterone years later. Females are also more likely to stop. In US military health records (Roberts et al. 2022), about 36% of transmasculine patients had stopped hormones within four years, compared with 19% of transfeminine patients. Prescription records cannot show why people stopped.

Known risks

The table lists the known and suspected medical risks of each treatment, with how strong the evidence is (certainty grades such as "very low" are explained on the evidence reviews page). Most of the evidence comes from observational studies with limited follow-up. Weak evidence means a risk is uncertain, not that it has been ruled out. Risk is also a separate question from reversibility, which is covered in the table above: a change can be reversible and still harmful, and a risk can persist after the visible effects have faded.

Two points cut across the table. First, a common reassurance in trans communities is that hormones simply give people the risks of the other sex. Even where that holds, as with heart attacks in trans men, it is a large increase compared with the person's own baseline, accepted at a young age for decades. Where it does not hold, as with vaginal atrophy, there is no "other sex" comparison at all: no natal male has a vagina exposed to male hormone levels. Second, many risks appear only after years. The 2025 review followed most outcomes for a few years at most, and cardiovascular events in natal females appeared 7 to 109 months after starting (Miroshnychenko et al. 2025).

What detransitioners report

Detransitioners' accounts of medical harm are not a measure of how often harm happens. They come from a self-selected group, and some symptoms they describe may have other causes. But they show what the risks look like in a real life, and they often describe symptoms that clinicians did not expect or could not explain. In a survey of 237 detransitioners (Vandenbussche 2022), 62% gave health concerns as a reason for detransitioning, and medical help with complications was a common unmet need.

Females on testosterone describe blood pressure, cholesterol and blood sugar problems at a young age, hair loss, and above all vaginal and urinary atrophy:

I stopped because I had high blood pressure, was pre diabetic all my hair fell out ( not like male pattern baldness, like a body abusing steroids) and developed a gi issues as well as autoimmune disease. —thisonesathrowawway, detrans female

I was going to the doctor and receiving antibiotics for a "UTI" that was "undetectable" for months because my doctor was not trans-informed and didn't know about atrophy either… My urinary health has never returned to the same and I still have occasional flair ups although it has gotten better. —charlescaster, detrans female

first, my blood pressure SOARED, at 16 i was getting readings of like, 150/90… i had vaginal atrophy and cervix prolapse when i was 17… genuinely thought its what i needed to stay alive, that if i lost my testosterone i would actually die. nope. testosterone was what was killing me. —blitz-angel, detrans female, who started testosterone at 15

Males on estrogen describe sexual dysfunction that did not recover, chronic breast pain, and in long-term users, bone loss:

for me the sexual side effects of estrogen have never gone away, still have ED and testicular atrophy almost 5 years after stopping —MythicalDawn, detrans male

I wish I knew my chest would have hypersensitivity and pain permanently. I was only thinking about how I might look. I didn't think about how I'd feel. I wish I knew it could happen in just a couple weeks and there's no real way to experiment safely. —UniquelyDefined, detrans male

I began taking cross sex hormones by age 25 and have done that for over 30 years at this point. I have a number of health issues from doing that. Osteoporosis is a major problem and I am in pain daily from it. —Liminal_exp, socially trans, regrets entire transition

A theme across both sexes is that harms were not mentioned beforehand, and that doctors later dismissed them. These experiences are covered in more depth on iatrogenic harm, sexual function and the detailed hormone pages.

What the evidence says about benefits

Hormones are given because they are expected to relieve gender dysphoria and improve mental health and quality of life. Several independent systematic reviews have now looked at how strong that evidence is, mostly in young people:

• Miroshnychenko et al. 2025 reviewed 24 studies of hormones in people under 26 (study page). Evidence on gender dysphoria, depression, global functioning, bone density and suicide was low to very low certainty. The authors concluded that the evidence "does not exclude the possibility of benefit or harm".
• The University of York reviews for the Cass Review (England's independent 2024 review of youth gender services) found 53 studies of hormones in adolescents, only one of them high quality (Taylor et al. 2024). Moderate-quality evidence suggested mental health may improve during treatment, but for most other outcomes "no conclusions can be drawn".
• The Cass Review concluded that the evidence base for masculinising and feminising hormones is weak (Cass 2024). It recommended extreme caution before prescribing them to under-18s.
• Several European countries, including Sweden and Finland, have become more cautious after their own reviews found low-quality evidence (Block 2023).

These reviews have their critics. A 2026 Lancet viewpoint argues that systematic reviews of adolescent care are being misused to restrict treatment (The Lancet 2026), and many trans people report that hormones transformed their lives. But "low certainty" is not a political label. It means the available studies are too small, too short, too uncontrolled or too affected by drop-out to tell whether the improvement comes from the hormones. It could come from other support, from expectation, or from natural change over time.

Other data point in a worrying direction. A Finnish register study of over 2,000 young people referred to gender services (Ruuska et al. 2026) found that among those who had medical transition, psychiatric treatment needs rose sharply during follow-up. Among those on feminising treatment, they rose from about 10% to 61%. The study cannot prove the hormones caused this. It does contradict the expectation that hormones reliably improve mental health. For the suicide question specifically, see suicide and transition. For the full review landscape, see evidence reviews.

Long-term unknowns

Cross-sex hormones are now being started by more young people than ever before. That group's outcomes in middle and old age are unknown, because most long-term data come from older, mostly male, adult cohorts treated with different drugs.

We have never seen this many people under 25 starting on cross sex hormones. So those outcomes will depend on what happens to the large cohort that was born between 1995 and 2015. There is no data. This is a massive experiment. —Drgypsy, verified professional on /r/detrans

What is known about the long term is limited:

• Heart and blood vessels: testosterone's effects on blood pressure, cholesterol and red cells are consistent. Whether these add up to more heart attacks and strokes over decades in women who started young is not known.
• Bone: bone density is generally maintained while people take enough hormone. The risks fall on those who started on puberty blockers, who later have their gonads removed, or who stop hormones after gonad removal. Bone evidence in young people is very low certainty (Miroshnychenko et al. 2025).
• Cancer: Dutch cohort data show breast cancer is far more common in trans women than in men (de Blok et al. 2019). For trans men, decades-long data on the uterus, ovaries and remaining breast tissue do not exist.
• Death rates: the Amsterdam cohort found roughly twice the expected mortality, with excess deaths from heart disease, lung cancer, HIV and suicide, and no improvement since the 1970s (de Blok et al. 2021).

Many detransitioners name these unknowns as a reason for stopping. In a qualitative study of six UK detransitioned women (Lomax & Butler 2025), concern about testosterone's long-term effects was a factor for most participants.

For most people, it takes a few years to a decade to start having issues, which is part of why we don't know much about the medical effects… After I realized this wasn't healthy for me, I thought "How can this be my true self if it's going to hurt me to be this way?" —ButchPeace274, detrans female

The "honeymoon" effect

Many people describe feeling dramatically better soon after starting hormones, sometimes within hours or days, long before any physical change. Trans communities often call this gender euphoria and treat it as confirmation that the person is trans:

My whole life I was stressed, anxious, depressed. Within a week of starting e… silence. Just calm. Focus. Clarity. For weeks I just couldn't believe it… I thought it was just euphoria. But no… it's biological reality. —Sylvie_Ponders, trans woman (MTF)

I actually experienced the mood boost just hours after the shot, even on a low dose (may have been a placebo effect, but who cares if it is) —77th_Bat, trans man (FTM)

Detransitioners often interpret the same experience differently. There are at least three explanations that have nothing to do with identity:

1. Drug effects. Testosterone is an anabolic steroid with a known mood-lifting and energising effect in anyone. Estrogen and anti-androgens suppress libido and can feel calming. Neither effect shows that a person's brain "needs" the hormone.
2. Expectation. People start hormones after months or years of being told they will finally feel right. Strong expectation produces strong placebo responses.
3. Relief from deciding. Starting hormones can end years of agonising about whether to transition. That relief is real, but it is relief from uncertainty, not proof that the decision was correct.

I also loved how I felt on T and its effects… I assumed this was a signal that I was definitely trans and that my brain operated better on T. But clearly my reaction to the hormone had nothing to do with whether living as a man was right for me —DapperDhampir, detrans female

I would say my honeymoon phase was very short, a couple of months or so where I felt some brain fog lifting and becoming more connected to the world. The lowered libido also probably made me feel calmer generally. But I quickly went back to feeling dissociated but now with the addition of having even less energy. —christa-paffgen, detrans male

The honeymoon creates a real problem for consent. It arrives at exactly the time the permanent effects of testosterone are developing, and it makes people less likely to notice that they dislike those changes. Some detransitioners say the honeymoon lasted a year or more. Others describe the end of it, and the urge to chase it back with higher doses or surgery, in the language of dependence. The testosterone page discusses this in detail.

Patterns in detransitioner accounts

Beyond specific side effects, several recurring themes appear in /r/detrans discussions about hormones. These are patterns in a self-selected group, not measured rates.

"Just try it" is not a real option. A common idea in trans spaces is that people can try hormones for a few months and stop if they don't like them. Detransitioners push back hard on this, especially about testosterone, because the permanent changes start early and the drug changes how people feel about those changes.

because permanent effects start happening so early on T, you're basically accepting irreversible changes if you want any sort of meaningful 'trial run.' —Miseracordiae, detrans female

HRT isn't like spiritually attaining your true self or something like that. It's a process of radical body modification through chemicals. You won't know if it's the right decision just by emotional feel. —UniquelyDefined, detrans male

Hormones did not touch the underlying problem. Many detransitioners say their distress came from trauma, internalised misogyny, internalised homophobia, depression or autism, and that hormones masked it for a while without resolving it. In Vandenbussche's survey, 70% said they had realised their gender dysphoria was related to other issues.

getting diagnosed with GD is like getting diagnosed with a symptom of a bigger problem…and eventually after being on T for a while, years, you realize nothing actually changed and you still have the same issues you did when you started —ApottotheOcto, detrans female

Lifelong dependence. Hormones are not a course of treatment that ends. Anyone whose ovaries or testes have been removed must take some sex hormone for life to protect their bones and heart, whatever their identity. Several detransitioners say they had not imagined being an elderly person still reliant on a prescription.

Once you have a hysto you will be forever dependent on testosterone injections. A really powerful question I read once (that someone else asked) was if they really wanted to be a senior person and still be reliant on a weekly shot of T. —folkinghell

Stopping is hard too. Coming off hormones brings its own crash, and very few clinicians have a protocol for it. A review of detransition care (Butler & Hutchinson 2020) noted that extensive protocols exist for transitioning but none for detransitioning. See the testosterone cessation and estrogen cessation pages.

Trans perspectives

Many trans people describe hormones as the most important and positive step they have taken. Common themes on r/MtF and r/ftm are the end of constant suicidal thoughts, better concentration, relief from anxiety, and finally recognising themselves in the mirror. Some say they would take hormones even with no physical effect:

I would still take it even if it never changed a thing about me because it fixed my brain so I can actually function in the world. —Salamqnder, trans woman (MTF)

On risk, a common view is that hormones only bring a person's risks in line with the other sex:

HRT just gives you the same risks as a cis man. —PoorlyDressedDandy, trans man (FTM)

These experiences are real, and nobody who is content with their transition should be told otherwise. But they do not settle the questions above. Reports of immediate relief are exactly what the honeymoon effect would produce, and the most positive accounts usually come from people early in treatment. The "same risk as the other sex" argument is partly true for some outcomes, uncertain for others, and does not apply at all to effects such as vaginal atrophy. The real harm described on this site comes from permanent medical interventions given without fully informed consent, not from people who choose them knowing the risks.

Puberty blockers and DIY hormones

Puberty blockers

Puberty blockers (GnRH agonists such as leuprorelin and triptorelin) stop a young person's natal puberty. They are often presented as a "pause button", but in practice they are usually the first step of a medical pathway rather than a neutral pause. In a Norwegian national cohort and a 2025 US federal evidence review, 92–97% of adolescents who started blockers went on to cross-sex hormones (Nyquist et al. 2025, retracted 2026; US HHS 2025), and most adolescent hormone studies in the York review included young people who had first been on blockers (Taylor et al. 2024). England's National Institute for Health and Care Excellence (NICE) review rated every critical outcome, benefits and safety alike, as very low certainty (NICE 2020).

Key risks in brief (the full table is on the puberty blockers page):

• Bone density falls behind peers during suppression; in a reanalysis of patients from the Tavistock (England's former national youth gender clinic), up to a third had abnormally low bone density after two years (Biggs 2021), and recovery on later hormones is often incomplete, especially in males.
• Fertility and sexual development: blocking early puberty and moving straight to cross-sex hormones may mean mature eggs or sperm are never produced, and adult sexual function after early blockade has never been studied. See fertility and sexual function.
• Brain development is unknown territory: the Cass Review 2024 warned that brain maturation may be "temporarily or permanently disrupted", and only a handful of small human studies exist (Baxendale 2024).
• Pseudotumor cerebri (raised pressure in the skull) was added as a warning to US GnRH agonist labels in 2022 (FDA 2022, via Pediatric Endocrine Society).
• Identity consolidation: the Cass Review could not rule out that blockers themselves change the course of gender-identity development, locking in a path that might otherwise have resolved.

DIY hormones

DIY hormones are cross-sex hormones obtained without a prescription, from overseas online pharmacies, homebrewers or friends, and taken with no medical monitoring of blood counts, clotting, potassium or liver function. They carry every risk of prescribed hormones plus a second layer: unknown dose and purity, injection and infection risks, legal risk, and no assessment at all of other causes of distress. A WHO-commissioned systematic review found no studies of the safety of self-administered hormones (Kennedy et al. 2022). The DIY hormones page sets out why some trans people defend the practice and why many detransitioners oppose it.

Surgery

Surgery often follows hormones. Removing the ovaries or testes makes lifelong hormone use a medical necessity. See surgery, hysterectomy and orchiectomy.

Questions worth asking

Questions that detransitioners and clinicians raise, for anyone considering, taking or stopping hormones:

• Which changes are permanent, and could I live with them if my feelings change?
• Has anyone explored other causes of my distress, such as trauma, depression, autism, eating disorders, or difficulty accepting my sexuality?
• Could an early mood lift come from the drug or from expectation, rather than from "gender euphoria"?
• What is my personal and family risk of heart disease, blood clots, cancer and hair loss?
• What will happen to my fertility and sexual function, and have I considered preservation?
• If I stop, who will support me medically and emotionally?

The support directory lists gender-exploratory therapists and detransition support groups. See also transition regret, healing and recovery, the study archive, the video archive and /r/detrans statistics.

References

• Miroshnychenko, A. et al. (2025). Gender affirming hormone therapy for individuals with gender dysphoria aged <26 years: a systematic review and meta-analysis. study page, source.
• Taylor, J. et al. (2024). Masculinising and feminising hormone interventions for adolescents experiencing gender dysphoria or incongruence: a systematic review. Archives of Disease in Childhood. source, York research database.
• Cass, H. (2024). Independent review of gender identity services for children and young people: Final report. study page, source.
• Block, J. (2023). Gender dysphoria in young people is rising—and so is professional disagreement. BMJ. study page, source.
• Systematic reviews and the needs of the adolescent transgender health care field (2026). The Lancet (viewpoint). source.
• Ruuska, S. et al. (2026). Psychiatric Morbidity Among Adolescents and Young Adults Who Contacted Specialised Gender Identity Services in Finland in 1996–2019: A Register Study. study page, source.
• Roberts, C. M. et al. (2022). Continuation of Gender-affirming Hormones Among Transgender Adolescents and Adults. study page, source.
• Littman, L. (2021). Individuals Treated for Gender Dysphoria with Medical and/or Surgical Transition Who Subsequently Detransitioned: A Survey of 100 Detransitioners. study page, source.
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• Vandenbussche, E. (2022). Detransition-Related Needs and Support: A Cross-Sectional Online Survey. study page, source.
• Lomax, J. & Butler, C. (2025). Narratives of Adults Registered Female at Birth Who Started a Medical Transition and Later Detransitioned. study page, source.
• Butler, C. & Hutchinson, A. (2020). The pressing need for research and services for gender desisters/detransitioners. study page, source.
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• Incidence of prostate cancer in transgender women in the US: a large database analysis (2025). Prostate Cancer and Prostatic Diseases. source.
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• BASHH. Best practice statement on the management of testosterone-associated vulvovaginitis. source.
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• Mayo Clinic. Masculinizing hormone therapy (via Mayo Clinic Health Library). source.
• Planned Parenthood Columbia Willamette. Gender-Affirming Hormone Care. source.
• Planned Parenthood North Central States. Gender Affirming Care. source.
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• NICE (2020). Evidence review: gonadotrophin releasing hormone analogues for children and adolescents with gender dysphoria. source.
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