DIY HRT carries real risks, including blood clots and, with cyproterone acetate, meningioma, that supervised care actively monitors for and manages. Some people choose DIY because supervised care is inaccessible, too slow, or too gatekeeping-heavy. Understanding the specific risks, what good monitoring looks like, and how to reduce harm matters whether you are supervised or not.
Why are we even talking about DIY HRT?
I want to start here because I think it matters. The existence of DIY HRT is not a failure of trans people's judgement. It is a failure of healthcare systems to provide timely, respectful, accessible care. When NHS waiting lists run to years, when private care costs more than people earn, when assessment processes feel designed to catch you out rather than help you, people make the entirely rational decision to take things into their own hands. I have heard this from so many trans people over the years. They are not reckless. They are resourceful, often desperate, and they deserve honest information rather than a lecture about why they should wait.
So this is not a piece about why you should not do DIY HRT. It is a piece about what the actual risks are, what supervised care does to manage them, and what you can do to protect yourself if supervision is not available to you.
What supervised HRT actually looks like
Good gender-affirming hormone care, as described in the WPATH Standards of Care 8 and the Endocrine Society guidelines, is not complicated in principle. You start at a low dose, build up gradually, and test your blood at regular intervals to see what your hormone levels, blood counts, liver function, and other markers are doing. The prescribing clinician adjusts the dose based on what the tests show and how you are feeling. That is the whole shape of it.
The monitoring exists because hormones do things in the body beyond making you feel like yourself. Some of those things need watching. The key ones are different depending on what you are taking.
Oestrogen and the risk of thrombosis
Oestrogen increases the risk of venous thromboembolism, which means blood clots, including deep vein thrombosis and pulmonary embolism. This is a real risk, not a theoretical one, and it is dose-dependent: higher doses carry more risk. The risk is also higher if you smoke, if you have a clotting disorder, if you are significantly overweight, or if you are taking oestrogen in a form that passes through the liver rather than being absorbed directly through the skin or mucous membranes.
This is why the move towards transdermal oestrogen, patches, gels, and sprays, has been significant in gender-affirming care. Transdermal oestrogen largely bypasses the liver's first pass, which means it produces fewer clotting factors than oral oestrogen at equivalent doses. The Endocrine Society guidelines reflect this preference. Supervised care will typically consider your personal risk factors and choose the route of administration accordingly. If you are doing DIY, knowing this matters: transdermal is generally safer than oral, particularly if you have any of the risk factors above.
Monitoring in supervised care includes baseline clotting history, awareness of symptoms to watch for, and where there is clinical concern, blood tests. If you are going without supervision, the harm reduction equivalent is: know the symptoms of a blood clot (swelling, redness, pain in a leg; sudden breathlessness or chest pain), take them seriously, and go to an emergency department immediately if they appear. This is not something to manage at home.
Cyproterone acetate and meningioma
This is the one that deserves its own section, because it has emerged clearly in recent years and is not yet as widely known as it should be. Cyproterone acetate, often called CPA and known by the brand name Androcur among others, is a progestogen with strong anti-androgenic properties. It has been widely used as part of feminising HRT, particularly in Europe, because it effectively suppresses testosterone. In some countries, particularly the UK, it is not licensed for this indication but has been used off-label.
The link between cyproterone acetate and meningioma, which is a tumour of the meninges, the membranes surrounding the brain and spinal cord, is now well established. The risk appears to be dose-dependent and cumulative: it is associated with higher doses taken over longer periods. At the doses sometimes used in gender-affirming care, particularly older prescribing practices that used higher doses, the risk is clinically meaningful. French pharmacovigilance data has been particularly clear on this, and regulatory agencies across Europe have responded with updated guidance recommending lower doses, shorter durations, and regular review.
For people doing DIY with CPA, this is important information. The historical high doses were unnecessary as well as risky: lower doses achieve adequate androgen suppression in most people. If you are using CPA, the harm reduction approach is to use the lowest effective dose, not to take it indefinitely without review, and to be aware of symptoms that might suggest a meningioma, including persistent headaches, vision changes, or neurological symptoms, and to seek medical attention if they arise. A meningioma found early is far more manageable than one found late.
It is also worth knowing that CPA is not the only option for anti-androgen therapy. Spironolactone is widely used, particularly in North America, and does not carry the meningioma risk. Bicalutamide is used in some contexts. The choice depends on what is available to you, your personal risk factors, and, in supervised care, clinical preference. If you are using DIY and CPA is what you have access to, knowing the alternatives exist is still useful, because it may inform what you ask for if you ever do access supervised care.
Testosterone and polycythaemia
For trans men and transmasculine people taking testosterone, the main physiological risk to monitor is polycythaemia, which means an excessive increase in red blood cell count and haematocrit. Testosterone stimulates red blood cell production, and if the haematocrit rises too high, blood becomes thicker and more prone to clotting, which increases the risk of stroke and other cardiovascular events.
This is why blood tests in supervised testosterone care routinely include a full blood count. If haematocrit is creeping up, the prescriber can lower the dose, change the frequency of administration, or, where necessary, refer for phlebotomy (therapeutic blood removal). The risk is real but very manageable with monitoring.
In DIY, the harm reduction approach is to try to access a blood test, even through a general practitioner, even without disclosing the reason if you do not feel safe doing so. A full blood count is a basic and inexpensive test. If your haematocrit is high, reduce the dose or frequency while you work out how to access proper oversight. Symptoms of polycythaemia can include headaches, dizziness, flushing, and blurred vision.
Getting dosing wrong in either direction
One underappreciated risk of DIY HRT is not a specific medication effect but simply dosing incorrectly. Too low a dose means inadequate feminisation or masculinisation, prolonged dysphoria, and unnecessary distress. Too high a dose means a greater load of side effects, higher cardiovascular risk, and in the case of oestrogen, paradoxically suboptimal feminisation because very high oestrogen levels can down-regulate receptor sensitivity.
Supervised care uses blood tests to check that hormone levels are in the right therapeutic range, not just present but genuinely at the level associated with the effects you are looking for. DIY without any testing is essentially flying blind on dosing. The practical harm reduction here is to seek blood tests wherever you can access them. Some general practitioners will test hormone levels if asked, even without knowing the context. Some private labs offer self-pay testing without a referral. Some harm reduction services and trans health organisations have developed resources to help people navigate this.
Why harm reduction matters more than abstinence messaging
The honest reality is that telling people not to do DIY HRT, when the supervised alternative is unavailable or years away, is not harm reduction. It is harm displacement. People will still take hormones. The question is whether they do so with good information or without it.
What genuinely reduces harm is: knowing the specific risks of what you are taking, choosing safer formulations and routes where possible (transdermal over oral oestrogen, lower doses of CPA), getting blood tests wherever you can, knowing the symptoms that require urgent medical attention, and pushing for supervised care in parallel rather than instead. If you are in a country where GenderGP operates, they can provide supervised prescribing and monitoring for people who cannot access it through public services: you can find them at gendergp.com.
None of this means DIY is without risk. It carries more risk than well-managed supervised care, for the straightforward reason that supervised care monitors and adjusts. But the comparison that matters is not DIY versus ideal supervised care. For most people doing DIY, the real comparison is DIY versus nothing, and nothing is not safe either.
What to do if you are currently doing DIY HRT
Keep trying to access supervised care, whether that is through your public health system, a private provider, or an organisation like GenderGP. In parallel: know what you are taking and why, understand the specific risks attached to it, get blood tests where you possibly can, know what symptoms to take seriously, and do not let fear of being judged stop you from seeking medical attention if something feels wrong. Most emergency departments and general practitioners will treat the presenting problem without shaming you for how you came to need help.
The goal is to get you to a place where someone who knows what they are doing is looking at your results alongside you. That is what supervised care does. It does not have to be perfect, and it does not have to be ideal, but it is better than guessing alone.
If there is a topic that you would like me to cover, just let Sammy know.
Dr Helen Webberley is a gender specialist, medical educator, and advocate, and the founder of GenderGP. She writes about gender identity, trans healthcare, and the lives of trans people with honesty and care.
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