Puberty blockers Archives - Stats for Gender

Puberty blockers disrupt the normal timing of puberty relative to same-age peers, with associated psychosocial effects

A 2024 systematic review noted that puberty blockers disrupt the normal timing of pubertal development relative to same-age peers. Puberty is an important developmental phase associated with identity formation, body image, emotional development, and peer integration.

Broader adolescent research has associated variations in pubertal timing with psychosocial outcomes including mood difficulties, social challenges, and depressive symptoms.

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

Puberty blockers

The combination of puberty blockers followed by cross-sex hormones leads to permanent loss of fertility

A 2024 systematic review notes that puberty suppression alone does not necessarily eliminate future fertility, as endogenous puberty may resume after treatment stops. However, when puberty blockers are followed by cross-sex hormones, fertility potential may be significantly impaired or permanently lost, particularly if fertility preservation has not occurred beforehand. This review therefore highlights that fertility risks emerge through the sequential treatment pathway from puberty suppression to cross-sex hormones.

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

A systematic review found increases in BMI during puberty blocker treatment, particularly among females

A 2024 systematic review reported that 39% of biologically female participants were classified as overweight prior to beginning puberty blockers. During treatment, increases in BMI-SDS were observed, particularly among biologically female participants, alongside alterations in expected growth trajectories.

The review noted that the available evidence remains limited by small sample sizes, heterogeneity between studies, and the observational nature of the data.

Jazz Jennings, star of the reality TV series I Am Jazz, began puberty blockers at age 11. Jennings gained substantial weight (nearly 100 pounds / ~45 kg) after starting blockers and cross-sex hormones, reaching morbid obesity (over 200 lbs / 90+ kg) at one point, which further complicated surgical preparation and recovery. (TLC, 2022).

^{TLC. (2022, January 25). Jazz is heartbroken by her weight gain | I Am Jazz [Video]. YouTube. https://www.youtube.com/watch?v=MSv3vq6L-fA}

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

Puberty blockers

Puberty blockers impair genital development and may complicate later surgical outcomes

Suppressing puberty alters normal genital and bodily development, which may affect later surgical options and outcomes. Reviews of the evidence have raised concerns that reduced genital tissue development following puberty suppression can limit surgical options – for example, by making standard penile inversion vaginoplasty impossible – and increase the complexity of later genital surgeries.

Prominent examples include:

In the seminal Dutch cohort (de Vries et al., 2014), an 18-year-old patient died from necrotizing fasciitis and sepsis following intestinal (sigmoid) vaginoplasty. Due to early puberty suppression, there was insufficient penile tissue for the standard surgical technique, necessitating the use of a higher-risk bowel segment procedure.
Jazz Jennings, star of the reality TV series I Am Jazz, began puberty blockers at age 11. This resulted in insufficient penile tissue development, requiring a more complex vaginoplasty using additional tissue sources, including peritoneal tissue and skin grafts. Jennings later experienced severe post-operative complications, including wound separation and splitting of the neovagina, necessitating multiple revision surgeries (TLC, 2018). Jennings also gained substantial weight – nearly 100 pounds (~45 kg) – after starting puberty blockers and cross-sex hormones, at one point reaching morbid obesity (over 200 lbs / 90 kg), which further complicated surgical preparation and recovery (TLC, 2022).

Observational studies have also reported changes in growth, bone development, and BMI during and after treatment with puberty blockers, although the available evidence remains limited and methodologically weak. Long-term outcomes remain insufficiently studied (Taylor et al., 2024).

^{de Vries, A. L. C., McGuire, J. K., Steensma, T. D., Wagenaar, E. C., Doreleijers, T. A. H., & Cohen-Kettenis, P. T. (2014). Young adult psychological outcome after puberty suppression and gender reassignment. Pediatrics, 134(4), 696-704. https://doi.org/10.1542/peds.2013-2958}

^{Taylor, J., Mitchell, A., Hall, R., Heathcote, C., Langton, T., Fraser, L., & Hewitt, C. E. (2024). Interventions to suppress puberty in adolescents experiencing gender dysphoria or incongruence: A systematic review. Archives of Disease in Childhood, 109(Suppl 2), s33-s40. https://doi.org/10.1136/archdischild-2023-326669}

^{TLC. (2018, September 8). Jazz experiences complications post surgery | I am Jazz [Video]. YouTube. https://www.youtube.com/watch?v=rU-uzjzNCVc}

^{TLC. (2022, January 25). Jazz is heartbroken by her weight gain | I Am Jazz [Video]. YouTube. https://www.youtube.com/watch?v=MSv3vq6L-fA}

^{University of California San Francisco, Gender Affirming Health Program. (2016, June 17). Vaginoplasty procedures, complications and aftercare. UCSF Transgender Care. https://transcare.ucsf.edu/guidelines/vaginoplasty}

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

Puberty blockers

Systematic reviews carried out on the impact of the treatment of puberty blockers or cross-sex hormone for minors show that medical transition has no evidence base

The UK NICE evidence reviews (2020), examining both puberty blockers and cross-sex hormones for minors with gender dysphoria, found no reliable evidence of significant improvement in gender dysphoria, mental health, body image, or quality of life outcomes.

Zepf et al.’s Beyond NICE systematic review (2024), which evaluated newer studies published after the NICE reviews, similarly concluded that the evidence base remains methodologically weak and insufficient to support reliable conclusions regarding benefits or long-term outcomes.

The HHS evidence review (2025), Miroshnychenko et al.’s systematic review and meta-analysis (2025), the NICE reviews (2020), and Beyond Nice (2024) systematic review have consistently identified low-quality evidence, methodological weaknesses, limited long-term follow-up, and substantial uncertainty regarding the effects of puberty blockers and cross-sex hormones in minors with gender dysphoria.

^{Miroshnychenko, A., Roldan, Y., Ibrahim, S., Kulatunga-Moruzi, C., Montante, S., Couban, R., Guyatt, G., & Brignardello-Petersen, R. (2025). Puberty blockers for gender dysphoria in youth: A systematic review and meta-analysis. Archives of Disease in Childhood, 110(6), 429-436. https://doi.org/10.1136/archdischild-2024-327909}

^{National Institute for Health and Care Excellence (NICE). (2020). Evidence review: Gonadotrophin releasing hormone analogues for children and adolescents with gender dysphoria. NHS England and NHS Improvement.}

^{Available at: NICE Evidence Review PDF}

^{National Institute for Health and Care Excellence (NICE). (2020). Evidence review: Gender-affirming hormones for children and adolescents with gender dysphoria. NHS England and NHS Improvement.}

^{PDF: NICE Evidence Review – Gender-affirming hormones for children and adolescents with gender dysphoria}

^{U.S. Department of Health and Human Services, Office of Population Affairs. (2025). Treatment for pediatric gender dysphoria: Review of evidence and best practices. Washington, DC: U.S. Department of Health and Human Services.}

^{URL: HHS Gender Dysphoria Report
PDF: Full Report PDF
Executive Summary: Executive Summary PDF}

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

All systematic reviews carried out on the treatment of puberty blockers on minors found no robust evidence that puberty blockers improve key psychological outcomes

Across systematic reviews of puberty blockers for minors, key clinical outcomes including gender dysphoria, quality of life, and body image showed no consistent or statistically significant improvements. Reported psychosocial benefits were inconsistent and difficult to distinguish from baseline differences or comparison conditions. Overall, the evidence base was rated as “very low certainty,” indicating substantial uncertainty regarding the reliability of the reported effects.

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972‘}

_{^{National Institute for Health and Care Excellence (NICE). (2020). Evidence review: Gonadotrophin releasing hormone analogues for children and adolescents with gender dysphoria.}}

^{NICE evidence review}

^{U.S. Department of Health and Human Services, Office of Population Affairs. (2025). Treatment for Pediatric Gender Dysphoria: Review of Evidence and Best Practices. Washington, DC.}

^{URL: HHS Gender Dysphoria Report}

^{PDF: Full Report PDF}

^{Executive Summary: Executive Summary PDF}

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972}

^{PDF: Full paper PDF}

Puberty blockers

The most up-to-date reviews of puberty blockers and cross-sex hormones for minors identify “significant conceptual and methodological flaws” in the evidence base.

Zepf et al.’s systematic review Beyond NICE (2024) found that the available evidence on puberty blockers and cross-sex hormones for minors with gender dysphoria remains limited. Existing studies are characterized by small sample sizes, weak methodology, missing data, high dropout rates, lack of appropriate controls, and limited long-term follow-up. The review also identified significant conceptual and methodological flaws across the literature, limiting confidence in reported findings and making reliable conclusions difficult.

Some studies report short-term reductions in gender dysphoria, depression, or suicidality following cross-sex hormones, but findings remain inconsistent and methodologically weak. Long term results remain unknown. In some cases, studies include no meaningful statistical analysis or suffer from substantial loss to follow-up, further limiting interpretation of outcomes and risks.

^{Zepf, F.D. et al. (2024). Beyond NICE: Aktualisierte systematische Übersicht zur Evidenzlage der Pubertätsblockade und Hormongabe bei Minderjährigen mit Geschlechtsdysphorie. Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1-21. DOI: 10.1024/1422-4917/a000972
PDF: Full paper PDF}

^{National Institute for Health and Care Excellence (NICE). (2020). Evidence review: Gonadotrophin releasing hormone analogues for children and adolescents with gender dysphoria. NHS England and NHS Improvement.}

^{PDF: NICE Evidence Review PDF}

^{National Institute for Health and Care Excellence (NICE). (2020). Evidence review: Gender-affirming hormones for children and adolescents with gender dysphoria. NHS England and NHS Improvement.}

^{PDF: NICE Evidence Review – Gender-affirming hormones for children and adolescents with gender dysphoria}

Bone mineral density that declines during puberty blockade may not fully recover with cross-sex hormone treatment.

A cohort study¹ of trans-identified people who had received puberty blockers and long-term cross sex hormones found that bone mineral density z-scores (which compare the patient with age- and sex-typical values) fell during puberty blockade, and did not fully recover following over a decade of cross-sex hormone treatment. This was especially the case for the lumbar spine of males receiving estrogen.

It is also notable that, of the original 143 eligible participants, only 75 completed this research. Of those who left the cohort, 6 (4%) had discontinued cross-sex hormone treatment and 27 (19%) could not be reached. These figures are consistent with high loss to follow up in other studies of so-called “gender-affirming care.”

van der Loos MATC, Vlot MC, Klink DT, Hannema SE, den Heijer M, Wiepjes CM. Bone Mineral Density in Transgender Adolescents Treated With Puberty Suppression and Subsequent Gender-Affirming Hormones. JAMA Pediatrics. 2023 Dec 1;177(12):1332-1341. doi: 10.1001/jamapediatrics.2023.4588. PMID: 37902760; PMCID: PMC10616766. ↩︎

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Boys receiving puberty blockers for gender dysphoria experienced irreversible changes to their testes.

A histological analysis¹ of testicular tissue taken from boys receiving puberty blockers for gender dysphoria showed that the tissue showed abnormal development that was likely to be irreversible.

Samples were gathered as part of “fertility preservation surgery,” in which testicular tissue is harvested and preserved in hope that it will be able to produce sperm later. Every boy with gender dysphoria in the study had elected for this surgery due to inability or reluctance to ejaculate. This suggests the possible presence of various psychological and physical conditions that are unexplored in the research.

Murugesh V, Ritting M, Salem S, Aalam SMM, Garcia J, Chattha AJ, Zhao Y, Knapp DJ, Kalthur G, Granberg CF, Kannan N. Puberty Blocker and Aging Impact on Testicular Cell States and Function. bioRxiv [Preprint]. 2024 Mar 27:2024.03.23.586441. Doi: 10.1101/2024.03.23.586441. PMID: 38585884; PMCID: PMC10996503. ↩︎

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Psychological effects of puberty blockers on young people may be worse than placebo.

An analysis¹ comparing psychological effects of puberty blockers on teenagers with gender dysphoria with existing research on placebo effects for various mental health conditions found that placebo effects appeared to be at least as strong as the effect of puberty blockers, if not stronger.

https://sex-matters.org/wp-content/uploads/2022/12/Teenagers-medication-vs-placebo.pdf ↩︎

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Depression symptoms got worse in children taking puberty blockers.

In a study¹ of 94 children with gender dysphoria, aged 8-16 and beginning to take puberty blockers, depression symptoms were more likely to get worse than to improve over two years of treatment. Scores on the Beck Depression Inventory (BDI-Y) went from 72% average, 10% mildly elevated, 10% moderately elevated, and 8% severely elevated at baseline to 75% average, 7% mildly elevated, 14% moderately elevated, and 9% severely elevated after 24 months.

This study was conducted from 2016 to 2021 by Dr. Johanna Olson-Kennedy. In 2024, the New York Times reported² Dr. Olson-Kennedy saying that publication of this research had been delayed because she feared that research showing that puberty blockers did not improve patients’ mental health would be “weaponized” against the use of puberty blockers by opponents of the practice. The report appeared as a pre-print, not peer-reviewed, in May 2025.

Johanna Olson-Kennedy, Liyuan Wang, Carolyn F. Wong, Diane Chen, Diane Ehrensaft, Marco A. Hidalgo, Amy C. Tishelman, Yee-Ming Chan, Robert Garofalo, Asa E. Radix, Stephen M. Rosenthal, Emotional Health of Transgender Youth 24 Months After Initiating Gender-Affirming Hormone Therapy, Journal of Adolescent Health, Volume 77, Issue 1, 2025, Pages 41-50, ISSN 1054-139X, https://doi.org/10.1016/j.jadohealth.2024.11.014. ↩︎
https://www.nytimes.com/2024/10/23/science/puberty-blockers-olson-kennedy.html
↩︎

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Women taking GnRH agonists for endometriosis experienced memory problems during treatment.

A study¹ of women taking GnRH agonists (a/k/a “puberty blockers”) to treat endometriosis found that 31% had “mild” memory problems, 25% had “moderate” problems, and 19% had “marked” problems. Problems were mainly with prospective and short-term memory.

Christopher Newton, Dianne Slota, Albert A. Yuzpe, Ian S. Tummon, Memory complaints associated with the use of gonadotropin-releasing hormone agonists: a preliminary study, Fertility and Sterility, Volume 65, Issue 6, 1996. ISSN 0015-0282. https://doi.org/10.1016/S0015-0282(16)58351-4. ↩︎

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The IQ of girls given puberty blockers for precocious puberty fell by eight points.

A study¹ of 15 girls treated with puberty blockers for central precocious puberty showed that IQ fell by around eight points. The average fell from 102 (55th percentile) to 94 (34th percentile). Two patients were held back a year at school.

In another study² of 30 children experiencing early puberty and treated with puberty blockers, IQ fell by around seven points.

Wojniusz S, Callens N, Sütterlin S, Andersson S, De Schepper J, Gies I, Vanbesien J, De Waele K, Van Aken S, Craen M, Vögele C, Cools M, Haraldsen IR. Cognitive, Emotional, and Psychosocial Functioning of Girls Treated with Pharmacological Puberty Blockage for Idiopathic Central Precocious Puberty. Frontiers in Psychology. 2016 Jul 12;7:1053. doi: 10.3389/fpsyg.2016.01053. PMID: 27462292; PMCID: PMC4940404. ↩︎
Mul D, Versluis-den Bieman HJ, Slijper FM, Oostdijk W, Waelkens JJ, Drop SL. Psychological assessments before and after treatment of early puberty in adopted children. Acta Paediatrica. 2001 Sep;90(9):965-71. doi: 10.1080/080352501316978011. PMID: 11683207. ↩︎

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IQ fell in a male patient whose puberty was blocked due to gender distress.

A case study¹ of a male patient whose puberty was blocked at age 11 showed a decline in several measurements of intelligence over the following three years, including decline of 10 points in global IQ and 15 points in verbal comprehension.

Verbal comprehension showed a continuous decline. Other measurements showed some improvement after an initial decline, but never recovered to baseline levels. Processing speed index scores initially improved, but then fell below baseline.

Schneider MA, Spritzer PM, Soll BMB, Fontanari AMV, Carneiro M, Tovar-Moll F, Costa AB, da Silva DC, Schwarz K, Anes M, Tramontina S, Lobato MIR. Brain Maturation, Cognition and Voice Pattern in a Gender Dysphoria Case under Pubertal Suppression. Frontiers in Human Neuroscience. 2017 Nov 14;11:528. doi: 10.3389/fnhum.2017.00528. PMID: 29184488; PMCID: PMC5694455. ↩︎

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Animal studies suggest puberty blockers may impair brain development, sometimes irrevocably.

A review¹ of studies of the effect of puberty blockers on animals (sheep, mice, macaque monkeys) suggests that brain development and neurological functioning may be compromised by the treatment. In some cases, hormone replacement (i.e. testosterone replacement in male sheep given GnRH agonists) did not mitigate or undo the observed changes. A variety of sex-specific effects were also observed.

Baxendale S. The impact of suppressing puberty on neuropsychological function: a review. Acta Paediatrica. 2024; 113(6): 1156-1167. doi:10.1111/apa.17150 ↩︎

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More patients on puberty blockers saw their distress deteriorate than improve.

A study¹ of children from 12-15 receiving puberty blockers via the Gender Identity and Development Service showed that 37-70% of patients showed no improvement in levels of distress. 15-34% showed deterioration, while only 9-29% showed improvement.

The highest rate of deterioration (34%) was recorded at the 12 month evaluation, when the sample size was at its largest. Evaluations at 24 and 36 months were affected by significant loss to follow-up, which compromises the data.

McPherson, S., & Freedman, D. E. P. (2023). Psychological Outcomes of 12–15-Year-Olds with Gender Dysphoria Receiving Pubertal Suppression in the UK: Assessing Reliable and Clinically Significant Change. Journal of Sex & Marital Therapy, 50(3), 315–325. https://doi.org/10.1080/0092623X.2023.2281986 ↩︎

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Rates of suicidality and self-harm did not improve in teenagers taking puberty blockers.

In a prospective study¹ of patients aged 12-15 referred to University College Hospital, London by the Gender Identity Development Service, patients on puberty blockers showed no change in rates of suicidality or self-harm.

This study is compromised by the lack of follow-up once patients reached the age of 16, meaning there were significant effective drop-out rates at 24 and 36 months.

Carmichael P, Butler G, Masic U, Cole TJ, De Stavola BL, Davidson S, Skageberg EM, Khadr S, Viner RM. Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK. PLoS One. 2021 Feb 2;16(2):e0243894. doi: 10.1371/journal.pone.0243894. PMID: 33529227; PMCID: PMC7853497. ↩︎

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The height of teenagers taking puberty blockers did not increase at an age-appropriate rate.

In a prospective study¹ of patients aged 12-15 referred to University College Hospital, London by the Gender Identity Development Service, patients on puberty blockers did grow taller, but not by as much as others in their age group.

Carmichael P, Butler G, Masic U, Cole TJ, De Stavola BL, Davidson S, Skageberg EM, Khadr S, Viner RM. Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK. PLoS One. 2021 Feb 2;16(2):e0243894. doi: 10.1371/journal.pone.0243894. PMID: 33529227; PMCID: PMC7853497. ↩︎

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Teenagers taking puberty blockers report more negative mood changes over time.

In a prospective study¹ of patients aged 12-15 referred to University College Hospital, London by the Gender Identity Development Service, patients reported increases in negative mood and decreases in positive mood over time since beginning puberty blockage.

This study is compromised by the lack of follow-up once patients reached the age of 16, meaning there were significant effective drop-out rates at 24 and 36 months.

Carmichael P, Butler G, Masic U, Cole TJ, De Stavola BL, Davidson S, Skageberg EM, Khadr S, Viner RM. Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK. PLoS One. 2021 Feb 2;16(2):e0243894. doi: 10.1371/journal.pone.0243894. PMID: 33529227; PMCID: PMC7853497. ↩︎

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The bone mineral density of teenagers taking puberty blockers did not increase to age-appropriate levels

In a prospective study¹ of patients aged 12-15 referred to University College Hospital, London by the Gender Identity Development Service, bone mineral density (BMD) in the hip showed no change from baseline over 36 months. Spinal BMD showed some increase at 24 months, but at no point did BMD show an age-appropriate increase.

This study is compromised by the lack of follow-up once patients reached the age of 16, meaning there were significant effective drop-out rates at 24 and 36 months.

Carmichael P, Butler G, Masic U, Cole TJ, De Stavola BL, Davidson S, Skageberg EM, Khadr S, Viner RM. Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK. PLoS One. 2021 Feb 2;16(2):e0243894. doi: 10.1371/journal.pone.0243894. PMID: 33529227; PMCID: PMC7853497. ↩︎

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Category: Puberty blockers