RU58841: Does It Cause Heart Damage?

TL:DR given the mixed reputation, I focused entirely on the safety of this compound. I think it unlikely for it to cause issues for those running testosterone in their cycles and/or those with normal to high levels of natural test. It may cause issues for those with low testosterone / DHT levels. Otherwise, a compound that is apparently highly effective for hair regrowth and preservation.

What is RU58841?

RU58841 is a nonsteroidal antiandrogen formerly under investigation, but since the patent ran out it’s no longer being evaluated. An antiandrogen is a compound that blocks androgen (i.e testosterone) in its various forms. Useful for treatment of enlargement and prostate cancer and early puberty. Side effects are those common to low testosterone - breast growth, sexual dysfunction, infertility etc. Finasteride, the common hair loss preventative, is another example of an antiandrogen.

I first became interested in RU58841 pretty recently. This morning in fact. My creaky joints are yearning for some of that sweet deca loving, yet finasteride and deca are a strict no-no due to their interaction. So I did the normal thing for /r/PEDsR, and started looking toward mysterious substances with a shaky reputation as my solution.

This reputation stems from its reported impact on heart function. The most famous example of this is a long one, but the TL:DR is that RU58841 as an antiandrogen occupied this fellas androgen receptors in the heart, turning away DHT (a form of testosterone) and causing heart damage.

A topical application that led to heart damage? Is that even possible? I started reading.

Medical Trials

  • Study 1: in 1994, researchers showed that RU58841 had high affinity for hamsters prostate and organ androgen receptors with weak systemic activity.
  • Study 2: in 1998, RU58841 suppressed DHT activation of androgen receptors, but may induce systemic side effects. On topical application, there was an increase in density, thickening and length of hair in monkeys with alopecia.
  • Study 3: This is a somewhat mythical study - double blind, randomised, vehicle-controlled, safety and tolerance study of topical PSK3841 solution at 5% administered twice daily over four weeks to health Caucasian males with androgenetic alopecia. Or in other words, exactly the kind of data we need to make a conclusive recommendation, and it’s of course suppressed. If anyone has academic access here, please let me know.

Androgen deprivation therapy can indeed lead to heart issues, though rare. Luteinizing hormone-releasing hormone (LHRH) receptor agonists in conjunction with antiandrogens seem to cause this increase in adverse cardiovascular events, with no events (that I can find) linked to just antiandrogens alone. LHRH agonists stop testicles from making testosterone or stop ovaries from making estrogen and progesterone, and I wouldn’t expect to find this as part of anyone’s stack… unless you’re cycling while also undergoing treatment for prostate cancer, or undergoing a sex change.

Antiandrogens have been shown to improve cardiac function in human and mice hearts with hypertrophy (bad in this instance) from increased levels of DHT. Specifically, cardiac health improved after being treated with finasteride. Finasteride also decreased mortality from long-term hypertrophy and prevented further progression of heart disease by decreasing DHT throughout the body, a cause of ventricular hypertrophy. This is interesting and is an area to dive into another time, and may lead to a recommendation to pair exogenous testosterone use with finasteride. Note that finasteride, like RU58841, has a mixed reputation within the PEDs world and I do not recommend it for folks without a test base - more on that another time.

What’s true for finasteride may not be true for RU58841 however - antiandrogens is a broad term, with major variations in differing types of compounds. There’s a list here, and while I read through them all, I don’t think I can draw many parallels between RU58841 and other antiandrogens. Contrary to what I read on forums or on, antiandrogens are indeed systemic. This is an important note as a non-selective compound means that it’s possible to have side effects in other areas - such as the heart, liver, CNS etc.


Do I think it’s possible that an antiandrogen can affect the heart then? Absolutely. How about one that’s topically applied? Based on what I learnt from transdermal applications, I’d say it’s plausible. My speculation is that where folks have low testosterone and DHT levels, the heart (or other major organs) truly are at risk of not receiving DHT, and develop arterial stiffness and presumably cardiac cell death. Where testosterone levels are mid to high, or exogenous testosterone is used (and assuming finasteride is not in the mix), DHT binding to androgen receptors is likely to continue at adequate levels. Keep in mind that DHT has a very strong binding affinity for androgen receptors - RU58841 has a relative binding affinity of only 5% the affinity of DHT.

I cannot reconcile the tragic story of the young man who by now has lost his life, but I have to think something else is going on here - DHT cannot be displaced by RU58841 and it just doesn’t make sense that his cardiac issues were caused by RU58841 unless he had little to no DHT to begin with. For those running exogenous testosterone and not running finasteride or another antiandrogen, my finding is that RU58841 can be utilized safely - at least in theory. Without the results for study 3 we only have anecdotes to go by.