Literature review: Testosterone, trans men, and insulin
TL;DR we're experimenting
This found hormone therapy worsens insulin resistance for trans women (males) and testosterone had no effect on trans men (females). However, you would expect a drug that improves lean muscle mass and reduces fat to improve insulin sensitivity, so the fact that it found no impact suggest it worsened it directly but this worsening was, at least in the short term in these susbjects, canceled out, resulting in no effect.
This one found the same thing, which is again, strange. Generally, if you have less fat, and more musscle, your insulin sensitivity is better, as your muscles are storing glycogen and your metabolism is higher so you are not storing as much of the calories as you eat as fat. So the fact that no effect is being found suggests there are effects in both directions that are canceling out, and more longitudinal studies are needed.
This study found that testosterone improves insulin sensitivity in transgender identifying females (trans men), confirming the complex effect interaction explaining the finding of no change in the first two studies.0*-=This study is nearly impossible to interpret because the authors don’t bother defining the terms ‘transgender males’ and ‘transgender females.’ However, it looks like the transgender females were actually males who identified as transgender, based on prescription of spironolactone. It found no effect of testosterone on insulin sensitivity despite metabolic changes normally that would predict0 improvements in insulin sensitivity, suggesting the effects are canceling out.
This study confirms that testosterone directly decreases circulating insulin levels and therefore should improve insulin sensitivity ceteris paribus, yet previous studies finding no effect suggest there are other metabolic impacts that contribute to a lack of change. This abstract also states bluntly, “Transgender men undergoing hormone therapy are at risk for insulin resistance….These results suggest that insulin resistance in transgender men may be due to suppression of the insulin-signaling pathway and decreased insulin sensitivity in white adipose tissue.”
Ovarian, breast, and metabolic changes induced by androgen treatment in transgender men (2021)3
"Metabolic effects of long-term androgen treatment in transgender men put them at par with cisgender men in terms of lipid profile, insulin resistance, and overall mortality. Body composition changes as desired after testosterone administration in most transgender men, and insulin resistance decreases with virilization”
Ths study confirms the potential for worsening it as well as the lack of hard data: “For transgender adults, CSHT has been associated with the potential for worsening CVD risk factors (such as blood pressure elevation, insulin resistance, and lipid derangements), although these changes have not been associated with increases in morbidity or mortality in transgender men receiving CSHT….The lack of randomized controlled trials comparing various routes and formulations of CSHT, as well as the paucity of prospective cohort studies, limits knowledge of any associations between CSHT and CVD”
Testosterone therapy for transgender men - PubMed (nih.gov) 2017
“A major limitation in the study of testosterone therapy for transgender men is a paucity of high-quality data due to a shortage of randomised controlled trials (partly because of ethical issues), few prospective and long-term studies, the use of suboptimum control groups, loss to follow-up, and difficulties in recruitment of representative samples of transgender populations.”
Overall, the quality of evidence was low, given the lack of randomized clinical/controlled trials and the small sample sizes. In conclusion, exogenous testosterone administration to transgender men was associated with modest increases in BMI, hemoglobin/hematocrit, and LDL-cholesterol, and with decreases in HDL-cholesterol. Long-term studies are needed to assess the long-term risks of testosterone therapy, particularly as they relate to cardiometabolic risks such as diabetes, dyslipidemia and the metabolic syndrome.
I heard you mention "gender atheist" exulansic shirt... Where do I find that?
"This study is nearly impossible to interpret because the authors don’t bother defining the terms ‘transgender males’ and ‘transgender females.’ However, it looks like the transgender females were actually males who identified as transgender ...."
Part and parcel of the rot that transgenderism has wrought, so to speak. Why there's some merit in deprecating if not anathematizing phrases like "transgender females" and "transgender women" in favour of "transfemales" and "transwomen". The first set -- as adjective-noun pairs -- more or less endorse the claims of those "self-identifying" as such to being members of the categories described and defined by the noun. The second set -- as compound words -- more or less repudiates or rejects such claims. Largely why transactivists get their knickers in a twist at the use of the second set:
https://en.wiktionary.org/wiki/trans_woman#Usage_notes
Along the same line, you might be amused by this analysis of the too-common use of "gender" to describe the sexes of fish:
https://www.tandfonline.com/doi/abs/10.1080/03632415.2012.687265
Who knew that fish had personalities? 😉
The only coherent use of "gender" is, largely, only as a synonym for personalities and personality types -- of which there are billions and billions. ICYMI, my kick at the kitty of trying to rationalize the concept of "gender", to put it on more of a scientific footing:
https://humanuseofhumanbeings.substack.com/i/64264079/rationalized-gender