Finasteride 1mg vs. 5mg: What's the Difference?

Kristin Hall, FNP

Reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Published 08/23/2020

Updated 05/12/2023

Going bald sucks. Finasteride does not. Millions of men use it every year to help them keep the hair they have and maybe even re-grow a lil bit of what they've lost.

Finasteride, the active ingredient in Propecia®, is an oral medication that’s designed to treat and prevent male pattern baldness. It was approved by the FDA to treat benign prostatic hyperplasia in 1992, and as a treatment for male pattern baldness in 1997.

Along with minoxidil, it’s one of two evidence-backed medications proven to help you keep and maintain your hair. In some cases, using finasteride could also help you regrow hair in areas of your scalp that have been affected by hair loss.

As an oral medication, it's sold in two different forms: finasteride 1mg tablets and finasteride 5mg tablets.

Below, we've discussed what both finasteride 1mg and 5mg are used for, how they work and which one might be best for you.

We’ve also covered the main differences between the 1mg and 5mg finasteride tablets that are available, along with information on which option is best for you. 

TL;DR Finasteride

Before we get into the specifics of finasteride 1mg and 5mg, it’s important to quickly go over the basics of how and why hair loss occurs in men, as well as how finasteride fits in as a medication for treating hair loss.

The list of what you should know about finasteride is long, but we’re here to focus on dosage-related topics, so here’s the bare-bones explanation:

  • Hair loss can occur for a variety of reasons, but most hair loss that affects men is the result of male pattern baldness, or androgenetic alopecia. This type of hair loss causes long-term damage to your hair follicles with the androgen hormone dihydrotestosterone (DHT).

  • DHT can bind to receptors in your scalp and cause your hair follicles to undergo a process referred to as miniaturization, resulting in the classic receding hairline that’s a common early sign of baldness.

  • Finasteride is part of a class of medications referred to as 5-alpha reductase inhibitors, or 5α-reductase inhibitors. The mechanism of action for these medications is to inhibit the effects of an enzyme called 5-alpha reductase, which is responsible for converting testosterone into DHT within your body. 

  • The 5-alpha reductase blockers like finasteride reduce DHT levels and slow down, stop or reverse the effects of male pattern baldness. They can also encourage hair regrowth and increase hair count.

  • Research shows that a normal dose of finasteride reduces DHT levels in your blood by as much as 70 percent compared with a placebo. It can also reduce DHT levels by 90 percent in your prostate gland, which can effectively treat androgenic alopecia and an enlarged prostate. 

For more information, check out the following resources:

Finasteride 1mg Uses

Now that you know what this stuff does, it’s probably a good time to discuss dosages.

Finasteride is most commonly used for hair loss at a daily dosage of 1mg. The majority of hair loss medications containing finasteride use this dose, including the original 1mg Propecia tablets.

Almost all studies of finasteride for hair loss also use this dosage. For example, a study published in the journal Dermatology in 2004 involved the use of 1mg finasteride for 12 months to treat male pattern hair loss, with 80 percent of men showing improvements.

But here's the thing — just because you CAN have more finasteride doesn't mean you NEED more finasteride. When it comes to treating hair loss, 1mg of finasteride per day is all it takes.

In fact, using more finasteride won't offer any improvements over what you'd get with 1mg, but you may open yourself up to a greater risk of experiencing side effects.

Finasteride 5mg Uses

Believe it or not, finasteride isn't ONLY used as a hair loss treatment — it can also treat certain health conditions related to your prostate. 

If you have benign prostatic hyperplasia (BPH), which is also known as an enlarged prostate, and you’re prescribed finasteride as a treatment, you’ll likely receive the 5mg dose of the medication.

This dosage of finasteride is often sold under the brand name Proscar®. It’s used specifically to control the growth of the prostate and reduce the severity of BPH symptoms. This dosage of finasteride is not used to treat hair loss. 

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Side Effects of Finasteride 1mg vs. 5mg

As we mentioned above, using more finasteride than you’re prescribed won't increase your hair growth, but may increase your risk of side effects.

And even at the correct dosage, finasteride — like all prescription medications — does come with a risk of side effects. 

The most commonly reported side effects for men taking finasteride are only reported by less than one percent of users, which would seem to indicate a low side effect risk overall. 

For those who do experience some adverse effects, the most common were decreased libido, erectile dysfunction and ejaculation disorder.

Discontinuation of both lower and higher doses due to sexual dysfunction was rare, though a small percentage did abandon use of finasteride. We get it — sex is sometimes more important than hair.

Here’s how these side effects vary based on dosage:

Side Effects of Finasteride 1mg

As with the medication finasteride in general, potential side effects of finasteride at a 1mg dose include the same big three:

Serious side effects from finasteride are highly uncommon, and with the smaller dose they were even less common. For example, decreased libido — the most common side effect of finasteride — only affects 1.8 percent of men who take it.

Side Effects of Finasteride 5mg

In comparison with the smaller dose, finasteride 5mg had a few additional prominent side effects, and a slightly higher severity of the side effects seen in the 1mg dose.

Clinical trials of finasteride 5mg found that 8.1 percent of men experience erectile dysfunction, with 6.4 percent of men reporting a reduced level of interest in sex and 3.7 percent reporting decreased ejaculation volume.

Additional adverse effects reported by men who use finasteride 5mg include rash, breast tissue enlargement and tenderness. 

Finasteride is not linked to any clinically significant drug interactions in either dose.

Finasteride and Prostate Cancer Risks

Although finasteride is associated with a reduced overall risk of prostate cancer, some scientific research from 1993 suggests that it may contribute to an increased rate of high-grade prostate cancer.

It’s a little hard to see a clear answer at the moment with the science we have access to. These findings are likely the result of confounding factors and detection bias, and there’s a high level of agreement within the scientific community that finasteride is safe for most men to use as a treatment for hair loss.

And in 2019, a newer study contradicted those older findings with a conclusion that — looking at 10,000 participants —finasteride was in no way associated with elevated risk of prostate cancer.

Our full guide to the side effects of finasteride goes into more detail about these issues, as well as the steps that you can take if you experience side effects while using finasteride. 

If you’re concerned about prostate health risks though, the best thing you can do is discuss your concerns with a healthcare provider.

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Other Forms of Finasteride 

There’s another way you can get finasteride working for your hair besides swallowing a pill — you can also apply finasteride directly to the hair, “Headon” style.

While topical finasteride is not yet approved by the FDA, it may be well on its way to approval. Recent clinical studies have found finasteride’s topical form to be just as effective as oral finasteride, but with one marked difference: it may actually be safer.

Aside from side effects risks like skin irritation associated with many topical products, topical finasteride may actually be safer because of its overall reduced footprint in your body — specifically, trials have shown that plasma concentrations are more than 100 times lower when you use topical finasteride vs. the oral version.

In other words, because it’s not cycling through your entire body, there are fewer organs, tissues and bodily functions that it can interrupt.

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Finasteride & Minoxidil

This is the FDA-approved dynamic duo. When used together, men saw better results in clinical trials compared to using either alone.

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Finasteride 1mg vs 5mg: Which Is the Right Dosage for Me? 

Finasteride is available as a 1mg or 5mg tablet. If you have male pattern baldness, you should only take finasteride at a dosage of 1mg per day. 

  • Taking finasteride at a higher dosage won’t do anything to reduce the severity of your hair loss, improve hair growth or speed up your results. 

  • However, it may increase your risk of developing side effects. 

  • Interested in getting rid of hair loss for good? We offer a range of proven, evidence-based hair loss treatments for men, including FDA-approved medications like finasteride and minoxidil

  • You can also try our shampoo and conditioner formulated to help with hair loss, and our combination minoxidil and finasteride spray.

14 Sources

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.

  1. Zito, P.M., Bistas, K.G. & Syed, K. (2022, May 8). Finasteride. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK513329/
  2. Cranwell, W. & Sinclair, R. (2016, February 29). Male Androgenetic Alopecia. Endotext. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK278957/
  3. Ho, C.H., Sood, T. & Zito, P.M. (2021, November 15). Androgenetic Alopecia. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK430924/
  4. Kinter, K.J. & Anekar, A.A. (2022, March 9). Biochemistry, Dihydrotestosterone. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK557634/
  5. Prostate Enlargement (Benign Prostatic Hyperplasia). (2014, September). Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/prostate-problems/prostate-enlargement-benign-prostatic-hyperplasia
  6. Zito, P.M., Bistas, K.G. & Syed, K. (2022, May 8). Finasteride. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK513329/
  7. Kaufman, K.D., et al. (1998, October). Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. Journal of the American Academy of Dermatology. 39 (4, Pt 1), 578-589. Retrieved from https://pubmed.ncbi.nlm.nih.gov/9777765/
  8. Hu, R., et al. (2015). Combined treatment with oral finasteride and topical minoxidil in male androgenetic alopecia: a randomized and comparative study in Chinese patients. Dermatologic Therapy. 28 (5), 303-308. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1111/dth.12246
  9. PROPECIA- finasteride tablet, film coated. (2021, June). Retrieved from https://www.accessdata.fda.gov/spl/data/3c8dff7e-41ab-46db-bacf-c41cc237f9d9/3c8dff7e-41ab-46db-bacf-c41cc237f9d9.xml
  10. Arca, E., et al. (2004). An open, randomized, comparative study of oral finasteride and 5% topical minoxidil in male androgenetic alopecia. Dermatology. 209 (2), 117-125. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15316165/
  11. PROSCAR- finasteride tablet, film coated. (2021, June). Retrieved from https://www.accessdata.fda.gov/spl/data/3e8b449e-a4c8-4e20-a32d-94b347a35f46/3e8b449e-a4c8-4e20-a32d-94b347a35f46.xml
  12. Badri, T., Nessel, T.A. & Kumar, D.D. (2021, December 19). Minoxidil. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482378/
  13. What are the steps of a hair transplant procedure? (n.d.). Retrieved from https://www.plasticsurgery.org/cosmetic-procedures/hair-transplantation-and-restoration/procedure
  14. What should I expect during my hair transplant recovery? (n.d.). Retrieved from https://www.plasticsurgery.org/cosmetic-procedures/hair-transplantation-and-restoration/recovery

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.