A 2021 literature review concluded that for trans women, even with testosterone suppression, "the data show that strength, lean body mass, muscle size and bone density are only trivially affected. The reductions observed in muscle mass, size, and strength are very small compared to the baseline differences between males and females in these variables, and thus, there are major performance and safety implications in sports where these attributes are competitively significant."
After 24 months of testosterone suppression, bone mass is generally preserved. The review states that no study has reported muscle loss greater than 12% with testosterone suppression even after three years of hormone therapy.
It found that trans women are in the top 10% of females regarding lean body mass and possess a grip 25% stronger than most females.
They suggest that instead of universal guidelines, each individual sport federation decide how to "balance between inclusion, safety and fairness" due to differences between sports.