Study Reveals Effectiveness of Testosterone Suppression in Trans Women

A new study tests how effective spironolactone and estrogen are at reducing testosterone levels in transgender women.

Appearing in the journal Endocrine Practice, the new study is the first to investigate the effectiveness of current treatments used in The United States that are aimed at reaching targeted and sustained levels of testosterone in transgender women over a period of several years. The purpose of the cross-sectional study was to assess the testosterone suppression achieved with spironolactone and estrogens.

Testosterone and estradiol levels were extracted using the electronic medical records of 98 anonymized transgender women who were treated with oral spironolactone and oral estrogen therapy at the Endocrinology Clinic at Boston Medical Center. Patients were divided into four similarly sized groups using the average estradiol dose they were administered over the course of their treatment. Current Endocrine Society guidelines suggest that patients should reach a serum testosterone <50ng/dl.

Only a quarter of transgender women taking the spironolactone and estrogen regimen were able to lower their testosterone levels within the usual female physiologic range. Another quarter could not achieve ideal female levels, but they remained below the male range virtually all of the time. One quarter of the women were unable to achieve any significant suppression of their testosterone levels.

Patients required an average of 9 months to reach steady testosterone levels overall, though the levels obtained varied from patient to patient.

Those who had a normal BMI (Body Mass Index) had higher testosterone while patients who had an obese BMI displayed lower testosterone levels throughout their treatment.

The age of the patient had no significant effect on testosterone levels.

"This study allowed us to identify patients who achieved differing levels of testosterone suppression, including a group of patients unable to achieve any significant testosterone suppression. These patients may have had difficulty adhering to their treatment or may have had a different physiologic response to treatment than other patients. On the other hand, patients who were able to achieve high levels of suppression may have adhered stringently to their treatment or had robust response based on physiology," explained corresponding author Joshua D. Safer, MD, FACP, associate professor of medicine at Boston University School of Medicine. "Also, it is not known if there is an absolute need for all transgender women to suppress the testosterone levels entirely into the female range. Perhaps it is acceptable for some to have levels just above the usual female upper limit."

The researchers believe future studies could pinpoint specific characteristics of patients who fall into each quartile of average steady state testosterone. "Identification of reasons why certain patients have better testosterone suppression could help improve anti-androgen therapy and allow for targeted interventions to advance the U.S. medical regimen for transgender women. As well, future study could determine the specific impact of testosterone at different levels even if not entirely in the female range," said Safer, who is also the Medical Director of the Center for Transgender Medicine and Surgery at Boston Medical Center.

The title should instead be, "Study reveals testosterone suppression fails for some trans women". This is good evidence of the poor practice still being followed.

Why? According to the article, 25% of women had no effect, whereas 50% had either supresson to female range or suppression to below male range "virtually all of the time". By your logic, the title "Study reveals testosterone suppression succeeds for majority of trans women" would be equally valid. It seems to me that all you're doing is trying to bias the title/article to align with your anti-spiro rhetoric. 🤔

You sure did write an article, however, you have a section starting with "Permit me to venture some personal opinions here" and includes an entire block titled "SOME ANECDOTAL EXPERIENCES". Red flags much? It's also littered with cherry-picked studies (I looked at all of them), many of which are only tangentially relevant and don't appear to support the argument. Not to mention a bunch of your references are links to other articles you have written. All you're doing is fear-mongering and trying to spread a conspiratorial, anti-establishment, message. I would caution anyone that reads Beverly's article to exercise some common sense and do your own research and talk to your endo/GP/specialist. I even encourage you to get a second opinion. This is exactly what I did and helped me to see through the nonsense. Oh, I am one of the 25% of women that Spiro doesn't work for.

LannahK, BeverlyCos

Testosterone or estrogen reduction, is a byproduct of supplying the body with a normal amount of testosterone or estrogen depending on ftm or mtf, once the appropriate level of hrt is reached the pituitary gland will not signal the gonads to produce their respective hormone, thus lowering the body’s level of that hormone, the pituitary gland does not distinguish between testosterone or estrogen it response to both of those hormones as if it they were the same hormone, nor does the pituitary gland care what the source of the hormones are, it simply tries to regulate them, so as long as the pituitary gland see's enough of a sex hormone it never sends the lh and fsh message to make more.

The only thing I know that can affect the suppression of testosterone or estrogen is a high levels of the Sex Hormone Binding Globulin (SHBG) which will “”bind”” both testosterone and estrogen to your red blood cells, thus preventing any testosterone or estrogen from reaching their given receptors, much like spironolactone Sex Hormone Binding Globulin (with a different action) prevents your body from utilizing either testosterone or estrogen, this action also prevents the pituitary gland from suppressing the hormone production of the gonads. AKA, free or bound testosterone or estrogen.

Spironolactone does not reduce testosterone, spironolactone sits on the individual receptors of the cells that are capable of receiving testosterone, spironolactone blocks testosterone from reaching the cells with testosterone receptors, thus blocking any messaging to the cells that can respond to testosterone, spironolactone does not prevent the conversion of testosterone to dihydrotestosterone or the effects of dihydrotestosterone for that you will need finasteride or equivalent. The other and main benefit of spironolactone is that it is a diuretic which can help with any fluid retention from estrogen. In my experience there is no need or good to be had from high doses of spironolactone, only low doses.

I am not a doctor, this is my experience, my doctor, and reading. Inotherwards not medical advice.


The authors state in the abstract that "measured serum estradiol levels did not change over time and did not correlate with dosage of estradiol administered," but the estrogen serum levels were not reported in the abstract, nor the dosages and method of administration. I am sure the observations are noted the full text of the article, where I predict we would read that none of the test subjects were taking estrogen by injection.

i take only estrogen and natural progesterone, no gestagen testo blocker or something, no androcur and no spiro, i had once only 120 estrogen then testo gone up to 6 again, so i took bit more estrogen and was at around 240 estrogen and tadaa testo is down to normal female levels :)

LaraMia I don't know what ""natural"" progesterone is, estradiol and progesterone from your doctor IS biologically identical to what the body makes, I don't know how much more natural you can get than that, now your progestin (equivalent to progesterone) and Premarin (equivalent to estradiol) are both synthetic, they are similar to what the body makes, they behave similarly in the human body, both progestin and Premarin have been found to be problematic in the trans community, Premarin was the hormone used in the w.h.o. heart study that stopped due to breast cancer risk. After you consider biologically identical or synthetic the only real difference is the delivery method.

“Biologically identical hormones or bioidentical hormones are derived from plants, such as the wild yam or soybean plant. The wild yam is rich in precursor molecules that can be converted into oestrogens and other hormones whose molecular structure is the same as those produced naturally in the human body”

Not medical advice.

The study proves that for the majority of patients, testosterone NEVER falls into the actual female range. Note the way you are seeing the phrasing elsewhere... "falling below male range" is useless to the transitioning AMAB person. It needs to be solidly and reliably in the female range, 6-86 ng/dl (total) and preferably in the bottom half of that range, under 50. And very few are achieving it with this method. I see one of the respondents above characterizes my paper as "conspiratorial" and "anti establishment" and I realize that there is a terrible moment of panic when you may first realize you have been treated in a suboptimum manner by your trusted professionals (who in turn, were relying on OTHER trusted professionals)... and it's normal to want to dismiss it. But look at the actual, detailed evidence. Follow the references and verify what they say. Do the math. Spiro as a mainstream treatment is now in its final years. There will be additional articles soon, and I will be a co-author on one or two of them, and no, I'm not talking about blog articles, but peer-reviewed articles in the WPATH Journal and elsewhere. If you'd like to read a bit more, see my talk at the USC School of Medicine on Feb 17th this year. Because it was spoken, there are no direct references in it, so you will have to go to the other articles for the actual references, but it sums up the situation pretty well. https://transhormones.wordpress.com/2018/02/17/4th-annual-socal-lgbtq-health-conference-talk/

Okay,y'all arguing about this, but y'all do realize this is for oral dosing only... Right?

One of the key problems with oral dosing of any medication is how it gets digested. Assuming your body absorbs 100% of the medication, this would be a complete study. But I'd be willing to bet money that is one of the first factors they look at in followup studies.

One of the interesting things I noted from this is that having a "high" BMI showed potential correlation to low T results. And yet, a high BMI often leads doctors to reject you as a candidate for GCS. If a reliable correlation can be found here, it might open up avenues for some of us who aren't skinny.

I'll also point out that starting, or observing, any scientific study with a clear bias means that you're no longer conducting a scientific study, so much as you're conducting a bias confirmation exercise.

Just a thought.

i have 0.4 testosteron without blockers, so it seems it works, and with natural i mean bio identical yes, but thats not the same like androcur for example, its called a gestagene too but has almost only the total opposite effect than progesterones has. here we not get spiro, we get here all androcur, and thats what i was meaning only, that is fully chemic gestagen and has absolutely no good effects except blocking of testosterone, while progesterone has masses of good effects, like prevention of chancer, demenz, epilepsy and much more, while androcur raises the risk of all that ^^ . except that all i met in my lfie so far who got high doses of blockers, had all through the line way too low estrogen with around 50-70 thats way under normal female levels, and with that low doses, the hypothalamus not stops sending LH that the body creates self sexual hormones still, but from some probably on everyone bit different level of estrogen in body, it stops it self to some level at least, whats left is then only the normal female level of testosterone, i dont know many anymore who take blockers today, the best endo docs changed that in last years, blockers are not needed, some only even "want" it cause they want almost totally 0 of testosterone, but thats not how it is on females.

I'm on a very low dose of estrogen once per week(.25ml of 20mg/ml strength estradiol valerate), and this alone does more than enough to suppress my testosterone without taking Spiro. We should be discussing why women are being starved of estrogen, rather than why they are not getting good results from a heart medication and low levels of estrogen.

Also, there is a large difference from bioidentical estrogen and progesterones, and synthetic stuff like premarin. I understand that it may be jarring that your doctor has been dosing you with substandard levels and harmful versions of estrogen/progesterone, but it's important to follow the trail. Good HRT requires better medicines, and higher estrogen levels.