Evidence map›Paper›PMID 33648944›Full record

SynthesisBritish journal of sports medicine2021

How does hormone transition in transgender women change body composition, muscle strength and haemoglobin? Systematic review with a focus on the implications for sport participation.

Joanna Harper, Emma O'Donnell, Behzad Sorouri Khorashad, Hilary McDermott, Gemma L Witcomb

Abstract readSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in British journal of sports medicine, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 42 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
42citing papers in PubMed, 3 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

42 citing papers in PubMed, 3 syntheses or guidelines pooled it.

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  14. Can Sex Competition Be Considered a Sport?Archives of sexual behavior · 2025
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4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors.

Joanna HarperSchool of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
Emma O'DonnellSchool of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
Behzad Sorouri KhorashadDepartment of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.
Hilary McDermottSchool of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
Gemma L WitcombSchool of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK G.L.Witcomb@lboro.ac.uk.ORCID http://orcid.org/0000-0003-4668-2441

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesWe systemically reviewed the literature to assess how long-term testosterone suppressing gender-affirming hormone therapy influenced lean body mass (LBM), muscular area, muscular strength and haemoglobin (Hgb)/haematocrit (HCT).

designSystematic review. DATA SOURCES: Four databases (BioMed Central, PubMed, Scopus and Web of Science) were searched in April 2020 for papers from 1999 to 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligible studies were those that measured at least one of the variables of interest, included transwomen and were written in English.

resultsTwenty-four studies were identified and reviewed. Transwomen experienced significant decreases in all parameters measured, with different time courses noted. After 4 months of hormone therapy, transwomen have Hgb/HCT levels equivalent to those of cisgender women. After 12 months of hormone therapy, significant decreases in measures of strength, LBM and muscle area are observed. The effects of longer duration therapy (36 months) in eliciting further decrements in these measures are unclear due to paucity of data. Notwithstanding, values for strength, LBM and muscle area in transwomen remain above those of cisgender women, even after 36 months of hormone therapy.

conclusionIn transwomen, hormone therapy rapidly reduces Hgb to levels seen in cisgender women. In contrast, hormone therapy decreases strength, LBM and muscle area, yet values remain above that observed in cisgender women, even after 36 months. These findings suggest that strength may be well preserved in transwomen during the first 3 years of hormone therapy.

Indexed as

SportsTransgender PersonsAdipose TissueAndrogen AntagonistsAthletic PerformanceBody CompositionCyproterone AcetateEstradiolFemaleHematocritHemoglobin AHumansMaleMuscle, SkeletalMuscle StrengthTestosteroneAndrogen AntagonistsCyproterone AcetateEstradiolHemoglobin ATestosteronebody compositiongender issuesphysiologypsychologystrength

Identifiers

PMID33648944
PMCPMC8311086

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.