The Claim

In transgender men undergoing masculinizing hormone therapy, 1.5-mile run performance fully normalizes to cisgender male levels within one year, with initial run times 15% slower than cisgender men improving to equivalent levels, indicating a significant endurance-enhancing effect of testosterone therapy.

Source: Effect of gender affirming hormones on athletic performance in transwomen and transmen: implications for sporting organisations and legislators

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
49score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

Trans guys on testosterone get just as good at running 1.5 miles as cis guys within a year — starting out about 15% slower but catching up completely thanks to hormone therapy.

See the scientific wording

Masculinizing hormone therapy in transmen leads to full normalization of 1.5-mile run performance relative to cisgender men within 1 year, with run times improving from 15% slower to equivalent levels, demonstrating a significant endurance enhancement effect of testosterone in transgender males.

What the research says

1 study

  1. Study: Effect of gender affirming hormones on athletic performance in transwomen and transmen: implications for sporting organisations and legislators

    The study found that transmen who started testosterone therapy went from being 15% slower to running just as fast as average cisgender men after one year, which matches the claim.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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