Medical Consequences of Detransition
Anyone who has medically transitioned and later detransitions will face lasting physical changes. Some of these changes are completely irreversible. The term ‘reversible’, which has often been used in information provided before and during transition, is incorrect for many of the effects described here. This page describes the medical reality as it is increasingly being documented — including aspects that have been systematically underemphasized in pre-transition information.
Related topics can be found in Medical Costs of Detransition and Side Effects of Stopping Hormones.
Irreversible Voice Changes (FTM)
Testosterone causes the vocal cords to lengthen and thicken. This effect occurs within a few months to a year. When testosterone is stopped, the voice does not return to its previous state. The lowered, male-sounding voice is permanent. For those who started as young women and later detransition, this is one of the most conspicuous consequences experienced in daily life: on the telephone, in shops, and whenever meeting a stranger, they are assumed to be male. Speech-language voice therapy may offer limited help in extending the vocal range, but the physical changes to the vocal cords themselves are permanent. More information about the permanent lowering of the voice and where to find help is available at transitieschade.nl.
Loss of Fertility
Loss of fertility is a core risk that has often been presented too lightly in pre-transition information. For those who started as children or young teenagers with puberty blockers followed by cross-sex hormones, without ever undergoing their own puberty, functional gamete tissue has in fact never developed. Fertility preservation is then impossible: there are no eggs or sperm cells to freeze.
In adults who use hormones for an extended period, fertility may decrease or disappear. In FTM individuals, testosterone can lead to anovulation and atrophy of ovarian tissue; the extent to which this is reversible after stopping is uncertain and cannot be guaranteed for each individual. In MTF individuals, estrogen can lead to a lasting reduction in spermatogenesis. Anyone who has undergone gonadectomy (removal of the ovaries or testes) is permanently infertile.
For young people who, at the time of treatment, simply could not foresee the consequences of being childless, this is a profound and growing point of criticism of the existing care model.
Sexual Dysfunction
Hormone therapy and surgery have a profound impact on sexual function. In MTF individuals, erectile function and libido are often substantially reduced or absent after long-term estrogen and anti-androgen use; recovery after stopping is variable and not always complete. After vaginoplasty, genital sensitivity may be reduced; orgasm is possible but different from before.
In FTM individuals, testosterone changes the genital anatomy (clitoral hypertrophy remains permanent) and the experience of sexuality. After phalloplasty or metoidioplasty, complications such as nerve damage, loss of sensation, and functional limitations are well documented.
A particularly serious category concerns young people who started puberty blockers before sexual maturation. They have never developed adult sexual function. International testimonies — including those in the Cass documents — describe anorgasmia and lasting sexual dysfunction as realistic outcomes, not rare exceptions.
Breast Tissue: Lasting Changes
A completed mastectomy (in FTM individuals) cannot be reversed. Breast reconstruction using implants and fat injections is possible, but it never restores the original tissue; nipple sensation remains limited or absent. For someone who underwent a mastectomy as a young teenager and later detransitions, this is a lifelong consequence of a procedure for which fully informed consent was impossible at that age.
In MTF individuals, breast development after estrogen is often partly permanent. A complete return to the pre-treatment anatomy is usually impossible; surgical removal always leaves scarring.
Complications Following Genital Surgery
Genital surgery has a significant complication profile that is rarely mentioned explicitly in information for the general public. Vaginoplasty can lead to fistulas (urethral or rectovaginal), stenosis of the neovaginal canal (making lifelong dilation necessary to keep the canal open), bleeding, granulation tissue, and chronic pain. Phalloplasty has one of the highest complication profiles in plastic surgery: urethral strictures or fistulas occur frequently, repeated revision surgery is the rule rather than the exception, and functional outcomes vary widely.
During detransition, these procedures cannot be reversed. Reconstructive surgery may, to a limited extent, contribute to a body that appears more like the original sex, but complete restoration is anatomically impossible.
Bone, Metabolic, and Cardiovascular Effects
Long-term use of puberty blockers during a phase in which bone density would normally be built up results in structurally lower peak bone mass. This increases the risk of osteoporosis later in life; see bone density during transition. For young people who later detransition, this is a lasting metabolic legacy. Cross-sex hormones also carry their own risks: estrogen increases the risk of thrombosis, while testosterone affects the lipid profile and possibly cardiovascular risk. After stopping, these effects partly normalize, but the damage incurred during the period of blocker use can no longer be made up.
Endocrine Dysregulation After Stopping
Abruptly stopping hormone therapy can cause symptoms including mood swings, hot flashes, fatigue, and changes in libido. Endocrinological guidance when stopping is medically indicated. In practice, this is poorly organized in the Netherlands — there is no established care pathway for detransitioners — and many patients stop on their own, with all the associated risks.
Aftercare: A Gap in the System
The Dutch healthcare system is designed for transition, not detransition. There are no specialized clinics for detransitioners. Endocrinologists, gynecologists, urologists, and plastic surgeons outside specialized gender centers rarely have experience with this specific patient group. The gender centers themselves are no longer a safe place for many detransitioners.
The Cass Review (United Kingdom, 2024) explicitly identified this gap and recommended establishing structural, non-stigmatizing aftercare services separate from affirmative clinics. In the Netherlands, that recommendation remains almost entirely unimplemented. At the same time, Cass — in line with the Swedish SBU and the Finnish COHERE evaluations — emphasizes that the evidence base for the original treatments is much weaker than was long presented: short follow-up periods, high dropout rates, and no control groups.