Scalp irritation after switching to 75 mg/mL RU‑58841 – what’s normal?

Posted by amber464 in Safety & Side Effects - 14 points, 4 comments.

I started using RU‑58841 a month ago after reading about its local DHT blocking. I mixed 75 mg of the powder into 1 mL of a propylene glycol‑based carrier and applied it every evening to the crown. For the first 5 days everything looked fine – no itching, no redness, and I could see a tiny bit of density improvement on the back of my head.

Around day 6 I noticed a mild tingling that turned into a dry, flaky patch where I’d applied the solution. It wasn’t painful, but the skin felt tight and a bit red after each dose. I tried diluting to 50 mg/mL and adding a few drops of a fragrance‑free moisturizer to the vehicle. The irritation lessened after a couple of days but didn’t disappear completely.

I’m wondering if anyone else has seen this “contact dermatitis‑like” reaction with RU‑58841 and if there’s a recommended way to mitigate it – maybe a different carrier, less frequent dosing, or a short break before resuming? Any bloodwork changes or systemic symptoms to watch for would also be helpful.

Comments

• reid664: I’ve tried RU‑58841 at 75 mg/mL a few times myself and got a similar dry, tight feeling after about a week. My guess is the propylene glycol is acting as an irritant once the skin barrier is a bit compromised by the DHT blockade. I switched to a simple ethanol‑water mix (70 % ethanol, 30 % water) and cut the dose to 40 mg/mL, applying every other night. The flaking faded within a few days and I haven’t seen any redness since. Did you try rinsing the scalp with a mild cleanser before each applic
• amber464: Yeah, I haven’t been rinsing – just patting the scalp dry after the usual shower. I’ll give a mild cleanser a try before each dose and see if it cuts down the residue. I also kept the 75 mg/mL because I wasn’t sure dropping that low would lose the density gain, but I might trial 40 mg/mL every other night like you did and compare the flaking. Thanks for the tip!
• shay_hrv: Yeah, I haven’t tried a pre‑wash yet but that sounds like a solid move. I’ll swap to the ethanol‑water mix and do a quick gentle rinse before each dose. Hopefully the barrier recovers faster than waiting another week. Thanks for the tip!
• amber464: Glad that tip resonated. I actually tried a quick water rinse before my next batch and the redness dropped noticeably after two days. I’m still using the ethanol‑water mix (70% EtOH, 30% distilled water) and keeping the concentration at 50 mg/mL. Will keep you posted if the barrier steadies or if I need to back‑off further. Thanks again!
• amber464: Sounds good – I actually started a gentle ethanol‑water (30/70) rinse last week after seeing the same tight feeling, and the flakiness dropped a notch after a couple of doses. I’m still keeping the moisturizer in the mix, but cutting the RU down to every other night helped my barrier bounce back quicker. Let me know how the pre‑wash works for you!

Community discussion - research and educational context only. Not medical advice.