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RU58841 vs Finasteride for Hair Loss: Benefits, Side Effects, and Research

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Sian Ferguson

Published 07/16/2024

If you’ve been looking into hair loss treatments, you might’ve come across a medication called RU58841. RU58841 is often presented as an alternative to finasteride — but which medication is better? 

Finasteride, sold under the brand name Propecia®, is one of the most popular medications for male pattern baldness. It’s available in both oral and topical form. 

RU58841, on the other hand, is a lesser-known topical treatment. It’s said to work similarly to finasteride — that is, by blocking the hormone that causes male pattern hair loss.

But does RU58841 work for hair loss, or is it all hype? And how does RU58841 compare to finasteride? 

Overall, finasteride is more well-researched than RU58841, and more accessible: RU58841 is generally hard to access. This could change in the future, however, if more clinical trials are conducted around RU58841.

Let’s look into the research on both medications and cover some alternative hair loss treatments.

Before we get into the weeds, let’s back up for a second and cover the basics of male pattern baldness. Know thine enemy, as they say. 

Male pattern baldness is the most common cause of hair loss in men. It goes by many names — you may also know it as androgenic alopecia, androgenetic alopecia, or male pattern hair loss.

(By the way, DHT is also responsible for female pattern hair loss. It’s basically the same hair loss condition as male pattern hair loss — just that it happens in women.)

This type of hair loss happens because of a hormone called dihydrotestosterone (DHT). DHT is a byproduct of testosterone; it has a number of important jobs during puberty and adolescence. 

But as you age, it can cause you (and your hairline) some issues. 

DHT can attach to androgen receptors in your scalp. This damages your hair follicles in a process called hair miniaturization. As a result, your hair grows thinner and weaker — and eventually, your hair strands won’t be able to push through your scalp. 

Unfortunately, male pattern hair loss isn’t a temporary problem. The issue can just get worse over time, unless you treat it. 

You can take a look at our guide to DHT and male hair loss for more detail.

As the name suggests, male pattern baldness causes hair loss in a specific pattern — for example, a receding hairline or bald patch at the crown of your head. 

There’s no cure for male pattern baldness. But certain hair loss treatments can help slow down male pattern baldness and prevent further hair loss. Some treatments even stimulate hair follicles to grow new hairs. 

One of those treatments? Finasteride. Another option is RU58841. Let’s get into the details of both. 

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RU58841 is a topical hair loss treatment. It’s also known as PSK3841 or HMR3841. We know the name isn’t super catchy or memorable, but bear with us.

RU58841 is a non-steroidal, anti-androgen compound that comes in gel or cream form. It's applied topically to the scalp, where it binds to androgen receptors. This blocks DHT from attaching to androgen receptors in the scalp, which means the DHT can’t damage the hair follicles. 

Since DHT is responsible for male pattern baldness, RU58841 basically slows down hair loss caused by DHT. However, RU58841 doesn’t actually stop your body from producing DHT itself.

But does RU58841 really work? It’s hard to say. There’s very little research on this topical anti-androgen — and much of the available research is old or not based on humans. 

For example, a 1997 study involved putting scalp grafts from balding men onto mice. The mice that were treated with a 1% RU58841 solution experienced some hair growth.  

And another 1997 study found that 5% RU58841 noticeably improved hair growth in stump-tailed macaques — a type of monkey. 

Aside from having very little human-based research available, RU58841 has never received approval from the Food and Drug Administration (FDA) as a treatment for hair loss. It’s also quite difficult to get a hold of in the US, and isn’t readily available to the average consumer.

So, while some internet sources might cite RU58841 as an alternative to finasteride, it really isn’t — at least, not right now. 

Okay, so we’ve covered RU58841. Now, what is finasteride?

Finasteride is a prescription hair loss medication that comes in oral and topical forms. Oral finasteride is FDA-approved for the treatment of male pattern baldness. This medication is also recommended by the American Academy of Dermatology

Finasteride is a 5-alpha-reductase inhibitor. This means that it blocks 5-alpha-reductase, which is the enzyme that helps your body turn testosterone into DHT. 

When you take oral finasteride, it lowers your overall DHT levels. As a result, DHT has less of an effect on your hair follicles, which means it slows down male pattern hair loss. 

Topical finasteride works similarly, except that you apply it directly to your scalp so that it blocks scalp DHT from affecting your hair follicles. 

The good news is that finasteride is a very well-researched, well-proven hair loss treatment. Decades of research back up the claim that finasteride slows down male pattern hair loss, and finasteride consistently outperforms placebos in human clinical trials.

And, despite what you may have heard, finasteride doesn’t actually lower your testosterone. It stops your body from converting testosterone into DHT, but it doesn’t affect your testosterone levels. 

While topical finasteride isn’t an FDA-approved treatment, you can still legally access it in the US. You will, however, need a prescription to get it. 

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Just as there’s a lack of research on RU58841’s benefits, not much is known about its side effects. 

As for the side effects of finasteride, that depends on whether you’re using oral finasteride or topical finasteride.

The potential side effects of oral finasteride include:

  • Sexual dysfunction (low libido, erectile dysfunction, or ejaculation problems)

  • Testicular pain

  • Headaches

  • Changes in mood or depression 

The potential side effects of topical finasteride include:

  • Headaches 

  • Lightheadedness

  • Skin irritation and itching 

With that said, many people use oral or topical finasteride with no problems at all. 

As with all medications, it’s possible to have an allergic reaction to finasteride — something to be mindful of. 

If finasteride is causing too many side effects for your liking, speak with the healthcare professional who prescribed it. They might suggest a different dosage or treatment. 

We’ve shared a lot of information about hair loss and available treatments. We’ve put together a quick summary to compare finasteride with RU58841 so you can review everything in one place. 

Here’s what you need to know:

  • RU58841 and finasteride are both said to help with male pattern baldness — neither medication has a mechanism to help with other types of hair loss. 

  • Both medications are DHT blockers — they inhibit DHT, which causes male pattern hair loss. 

  • RU58841 is not easily available in the US, but finasteride is. 

  • RU58841 only comes in topical form, while finasteride comes in oral and topical form.

  • Oral finasteride is FDA-approved for the treatment of hair loss, but RU58841 and topical finasteride are not approved by the FDA. 

  • Finasteride is extremely well-researched while RU58841 is not. 

While both RU58841 and finasteride target male pattern hair loss, finasteride has far more research backing it. That’s why finasteride is an easily available, FDA-approved treatment, while RU58841 is not.

Future research could shed more light on RU58841 and whether it’s a legit alternative to finasteride. But for now, we’re going to advise you to stick with proven hair loss treatments. After all, when it comes to putting something on your hair, it’s better to follow the science.

As we’ve explained, RU58841 isn’t yet a proven finasteride alternative. But there are some other options to treat hair loss if finasteride doesn’t work for you. 

For example, you could try:

  • Minoxidil. Also sold under the brand name Rogaine®, minoxidil is available in both oral and topical form. Topical minoxidil is an over-the-counter product that is FDA-approved for treating male pattern hair loss. We offer minoxidil foam and minoxidil solution online.

  • A minoxidil-and-finasteride combination. It’s safe and effective to use minoxidil and finasteride together to slow down hair loss and help regrow hair. We offer a finasteride and minoxidil spray, which is a topical treatment.

  • Hair growth supplements. Nutritional deficiencies can lead to hair loss. In addition to eating a varied and balanced diet, it may be a good idea to supplement your nutritional intake. Our biotin gummies contain a range of vitamins that support healthy hair growth.

  • Quality hair care products. Keeping your hair and scalp clean is essential for hair health. You can use shampoos that contain ingredients that may promote hair growth, like saw palmetto

  • Healthy hair habits. In addition to promoting hair growth, you also want to avoid habits that cause hair breakage. Avoid harsh chemical treatments and rough styling techniques.

  • In-office hair loss treatments. If you have some room in your budget, you might consider laser treatment or platelet-rich plasma (PRP) therapy. These treatments are usually done by dermatologists.

  • Hair transplants. Although these procedures are costly, hair transplant surgery can be very effective at regrowing hair on parts of your scalp that have been permanently damaged by male pattern baldness.

When it comes to hair loss prevention, time is of the essence. Male pattern hair loss gets worse over time when left untreated, so it’s important to take action ASAP to get your hair growing again. 

Remember that hair loss prevention isn’t a one-size-fits-all — what works for one person might not work for the next. If you’ve noticed the early signs of hair thinning, it’s a good idea to speak with a healthcare provider as soon as you can.

Hair loss treatments, delivered

When comparing RU58841 and finasteride, it’s clear that finasteride has far more research backing its use as a hair loss treatment. Also, it’s far easier to access finasteride than RU58841 — at least for now. 

Here are some key differences to keep in mind:

  • Both RU58841 and finasteride may treat male pattern hair loss. They’re both said to work by blocking the effects of DHT, the androgen that damages hair follicles and causes male pattern hair loss. 

  • But RU58841 is not well-researched. Most studies on RU58841 are small and conducted on animals, not humans. On the other hand, finasteride has been well-researched for many decades and is approved by the FDA.

  • There are alternatives to both. Not keen on finasteride? You can try hair loss treatments like minoxidil, DHT-blocking shampoos, and hair growth supplements to promote hair regrowth.

In many ways, the research on RU58841 may be exciting for those who are looking to treat and further prevent male pattern hair loss. Still, there’s very little research on the treatment, so it doesn’t inspire much confidence. 

When it comes to male pattern hair loss, the sooner you act, the better. You can start by contacting a healthcare professional. They can help by assessing your hair loss and discussing your treatment options with you. If you’d like, you can book an online hair loss consultation through our platform. 

7 Sources

  1. American Academy of Dermatology. (n.d.). Hair Loss: Diagnosis and Treatment. https://www.aad.org/public/diseases/hair-loss/treatment/diagnosis-treat
  2. De Brouwer B, et al. (1997). A controlled study of the effects of RU58841, a non‐steroidal antiandrogen, on human hair production by balding scalp grafts maintained on testosterone‐conditioned nude mice, British Journal of Dermatology. https://academic.oup.com/bjd/article-abstract/137/5/699/6682576?redirectedFrom=PDF
  3. Ho CH, et al. (2024). Androgenetic Alopecia. https://www.ncbi.nlm.nih.gov/books/NBK430924/
  4. Kinter KJ, et al. (2024). Biochemistry, Dihydrotestosterone. https://www.ncbi.nlm.nih.gov/books/NBK557634/
  5. Pan HJ, et al. (1998). Evaluation of RU58841 as an anti-androgen in prostate PC3 cells and a topical anti-alopecia agent in the bald scalp of stumptailed macaques. Endocrine.https://pubmed.ncbi.nlm.nih.gov/9798729/
  6. Uno H, et al. (1997). Dose-dependent and long term effects of RU58841 (androgen receptor blocker) on hair growth in the bald stumptailed Macaque. Journal of Investigative Dermatology. https://www.infona.pl/resource/bwmeta1.element.elsevier-391c502a-853e-3678-ad3c-1984832583e4
  7. Zito PM, et al. (2022). Finasteride. https://www.ncbi.nlm.nih.gov/books/NBK513329/
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Knox Beasley, MD

Dr. Knox Beasley is a board certified dermatologist specializing in hair loss. He completed his undergraduate studies at the United States Military Academy at West Point, NY, and subsequently attended medical school at Tulane University School of Medicine in New Orleans, LA. 

Dr. Beasley first began doing telemedicine during his dermatology residency in 2013 with the military, helping to diagnose dermatologic conditions in soldiers all over the world. 

Dr. Beasley is board certified by the American Board of Dermatology, and is a Fellow of the American Academy of Dermatology.

Originally from Nashville, TN, Dr. Beasley currently lives in North Carolina and enjoys spending time outdoors (with sunscreen of course) with his wife and two children in his spare time. 

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