Q: “Is trenbolone progestagenic? Or does trenbolone increase prolactin? A friend did a cycle of 500 mg/week testosterone plus 500 mg/week trenbolone enanthate and got gyno, when previously he’d done just the testosterone and did fine. This has me concerned about trenbolone.”
A: Trenbolone has near zero progestational activity, as found both in veterinary science and in cell studies. Its activation of the progesterone receptor (PR) is about 100 times weaker than that of progesterone itself. Trenbolone levels achieved during steroid cycles cannot activate the PR to even a small fraction as much as is caused by natural progesterone levels.
At least one veterinary study also found trenbolone to not increase prolactin measurably, despite depressing thyroid levels.
In your friend’s cycle, prolactin may well have increased. Where an aromatizing steroid is used and estrogen levels are not controlled with an anti-aromatase, estradiol levels typically rise. This often but not always causes an increase in prolactin, and sometimes a large increase.
It’s impossible to determine why gynecomastia developed for your friend this time but not on the previous occasion, particularly as no blood test was performed. Uncontrolled increase in estrogen due would certainly have contributed. Elevated prolactin caused by increased estrogen could be a contributor.
Authentic trenbolone actually works against estrogenic differentiation of the mammary gland, or at least this has been found in veterinary science.
It can be difficult to attribute cause when gyno occurs during trenbolone cycles. Sometimes, as in this cycle, other causes could completely explain it. In others, the trenbolone product seems the only possible cause.
When veterinary and pharmaceutical preparations were the only sources of trenbolone, gyno was never attributed to this steroid. It also appears never to occur when trenbolone is personally prepared from Finaplix H (not S.) For this reason, I doubt that authentic trenbolone can cause gyno.
However, underground preparations sold as trenbolone have promoted gyno in many cases. Whether this is due to substitution, oxidation of the material, or some other reason is unknown to me. I’d advise personally preparing from powder, having verified that the powder is moderately yellow, not brown, and is strongly spicy to the taste. This will at least make it highly likely that the product contains trenbolone. Another alternative is to prepare personally from Finaplix H. Doing so allows absolute certainty.
About the author
Bill Roberts is an internationally-recognized expert on anabolic steroids and performance-enhancing drugs (PEDs). He received a bachelor degree in Microbiology and Cell Science and completed the educational and research requirements for a PhD in Medicinal Chemistry at a major American university.
Bill entered the nutritional supplement industry prior to completing his doctoral thesis but his education was invaluable so far as being able to design/improve nutritional supplement compounds, since it was in the field of designing drug molecules and secondarily some work in transdermal delivery.
His education was not specifically "geared" toward anabolic steroids other than expertise with pharmacological principles having broad applications. This has allowed Bill to provide unique insight into the field of anabolic pharmacology with knowledge of points which he would not have known otherwise.
Nice article Bill…I think many people have the same misconceptions about tren as well as all 19-nor steroids. Body chemistry is biologically and functionally the same, but each persons body still can react differently to exogenous hormones …anyway, nice write up as always!
“Trenbolone has near zero progestational activity, as found both in veterinary science and in cell studies. Its activation of the progesterone receptor (PR) is about 100 times weaker than that of progesterone itself. Trenbolone levels achieved during steroid cycles cannot activate the PR to even a small fraction as much as is caused by natural progesterone levels.”
Nice write up Bill. Thank you.
Would you mind providing the research that covers these facts?