Let’s save you and me a lot of time. There is no scientific research on the hormonal effects of hormone replacement therapy on male biologics athlete transition to transwomen athletes.
“Because trans women have been struggling to get into women’s sport, they have established rules to alleviate the physical benefits that various governing bodies can have. But there has been a lot of debate about what these advantages are and how to deal with them – and whether this is necessary or not. ” New Yorker
And to equalize the field of definitions, gender reflects a variety of characteristics, defining and distinguishing what we might even call feminine or masculine. These traits may be our social roles, perceptions, or the presence or absence of biological chromosomes, organs, or hormones. Our culture, written from there, has subsequently redefined gender in terms of external appearance (phenotype), chromosome (genotype), and hormonal level, most recently in the case of runner Caster Semenya.
He wanted to isolate our scientific thinking du gender characteristic; thus, we ignore many other biological considerations, such as the relationship of one hormone to another and how hormone actions can increase and decrease over longer periods of time than a few weeks or months. A systemic review in the British Journal of Sports Medicine examines these considerations of equal importance.
In one meta-analysis, the researchers looked at 24 studies on “non-athletic transwomen” who suffer from gender-based hormone therapy (GAHT). This therapy generally includes an anti-testosterone agent and estrogen to reduce the masculinization and create a hormonal environment to promote feminization. There is no evidence that it creates the hormonal environment and cyclicality of a female cis.
The study examines all measures of muscle strength and oxygen delivery, arguably necessary but not sufficient factors for athletic performance.  They focused on three measures of muscle, muscle mass, muscle strength, and section area, and two measurements of resistance, hemoglobin, and hematocrit, indirect measures of oxygen transport and delivery efficiency. . Testosterone increases all of these measures, so presumably, and this is a crucial note, as anti-testosterone therapy will reverse these effects.
As with all meta-analyzes, there was a set of participants, GAHT therapy, study intervals, and type. More importantly,
- All of the studies involved a small number of participants, with the largest being 277 participants.
- While most transgender women “achieved testosterone levels in the reference range of cisgender women,” the various studies included had higher levels than generally accepted, which may confuse the results.
Let’s focus on qualitative findings rather than arguing the meaning of quantitative measures.
- Through GAHT therapy, all parameters of interest were reduced to different levels in transwomen.
- At 12 months, both muscle mass, muscle mass, and transverse muscle size were significantly reduced.
- But the loss of muscle strength ranged from insignificant to 7%. “… After 12-36 months, the GAHT suggests that transwomen are likely to maintain a strong advantage over women.”
- Transwomen’s hemoglobin and hematocrit, which provide oxygen essential for resistance, were the same as women in four months.
What to conclude:
Once again it is more complex than we thought. Attempts to “imitate” a female hormonal environment failed to make men women in terms of muscle mass and strength. Transwomen can be more easily compared with cis-women in the isolated aspects of physiology of oxygen delivery (hemoglobin and hematocrit). But the effect of extra muscle strength throws a spike in the theory that hormonal treatments can be “great equalizers”. This, as the author suggests, means that sports activities that require endurance may have a different balance between transwomen and ciswomen than sports activities that require strength.
“Although the level of sport is the same, it is important that women have the opportunity to participate in a meaningful competition in the women’s category. Whether transgender and transgender women can play a significant role in sports, even after the GAHT, is a hotly debated issue. ”
 Additional factors include upper and lower body proportions, coordination, training, perceptual skills, and experience.
 Hemoglobin is a molecule that transports oxygen throughout the body, and the hematocrit refers to the serum and proportion of red blood cells (which contain hemoglobin).
Source: How does the hormonal transition change the body composition, muscle strength, and hemoglobin of transgender women? A systematic review focusing on the implications for sports participation. British Journal of Sports Medicine DOI: 10.1136 / bjsports-2020-103106