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Understanding Finasteride Gynecomastia: Causes and Symptoms

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Grace Gallagher

Published 06/10/2024

Updated 07/25/2024

Is finasteride gynecomastia something you should be worried about when taking this medication for hair loss? Probably not, but it can happen in very rare cases.

If you’ve ever seen a drug commercial, you know all medications have side effects. Tiredness and appetite changes are one thing, but it can be especially concerning when a side effect changes your appearance.

This is why so many people wonder about finasteride gynecomastia (the development of breast tissue in men taking finasteride). To be clear, it’s something most men taking finasteride will not experience.

We’ll dive into the link between finasteride and gynecomastia and go over what signs to look out for. But in case you don’t stick around until the end (we forgive you), know that finasteride-induced gynecomastia is really uncommon.

Gynecomastia (sometimes spelled in medical literature as gynaecomastia) is the enlargement of male breast tissue. It’s a common condition that’s more a cosmetic concern than a clinical medical issue, though it can cause discomfort and pain.

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Gynecomastia occurs because of a hormonal imbalance. More specifically, it happens when there are excess estrogen levels in breast tissue and a lack of androgens (male sex hormones).

Gynecomastia can happen in men and women, but it’s more pronounced in men, as they — and this isn’t groundbreaking — don’t have breasts. (At least, typically not in the way we think of most women having breasts.)

Several things can contribute to gynecomastia. Research shows that drugs (including antiandrogens and some antipsychotics) account for about 20 percent of gynecomastia cases in men. We don’t have exact data, but finasteride is a tiny percentage of that.

Risk Factors for Gynecomastia

Gynecomastia always happens because of hormonal imbalances. But other things besides certain medications can alter hormones, leading to this condition.

Factors that may increase your risk of gynecomastia include:

  • Obesity

  • Aging

  • Puberty

  • Testicular tumors

  • Hormonal treatments for prostate cancer

  • Thyroid problems

  • Some types of cancer, like breast cancer

Klinefelter syndrome can also elevate the risk. This is when someone assigned male at birth (ASAB) is born with an additional X chromosome.

Sometimes, the cause of gynecomastia is unknown — one study found that to be the case in 65 percent of patients.

Gynecomastia itself isn’t rare — research estimates that it develops in 30 to 70 percent of men after adolescence. However, gynecomastia caused by finasteride is very uncommon. We’ll discuss this below.

Let’s get straight to the point: It’s possible for finasteride to cause gynecomastia, but it’s very rare.

We only have a handful of case reports showing a link between finasteride and gynecomastia.

Research published in 2024 found that there have only been eight reported cases of gynecomastia with low-dose (1 milligram daily) finasteride treatment since its approval for androgenetic alopecia (AGA or male pattern baldness) in 1997. But, as the analysis notes, this is likely due to underreporting, meaning there are probably more cases that were never diagnosed or treated.

While still rare, finasteride gynecomastia is typically associated with higher doses of 5 milligrams a day. This is the dosage used for treating benign prostatic hyperplasia (also called benign prostatic hypertrophy or BPH). The 1-milligram dose is what’s used for hair loss.

Before discussing the link between finasteride and gynecomastia, it’s important to touch on how finasteride works for treating male pattern baldness.

Male pattern baldness is caused by a combination of genetic factors and the effects of dihydrotestosterone (DHT), an androgen that plays a crucial role in male development in utero and during puberty.

But after puberty and into adulthood, DHT can bind to receptors in the scalp and cause hair follicles to “miniaturize” or stop producing new hairs. This process can lead to a receding hairline, a bald patch near the crown, and other signs of hair loss.

DHT is a byproduct of testosterone. Finasteride is in a class of medications called 5-alpha reductase inhibitors (or 5ARIs). It works by hindering an enzyme called 5α-reductase (5AR), which converts testosterone into DHT.

Finasteride’s Effects on Male Hormones

Finasteride significantly reduces DHT levels in the body. This is great news for your hair as the drug slows down — or sometimes entirely stops — follicular damage caused by DHT.

That means a thicker, fuller head of hair, especially around the hairline and crown, where hair follicles are particularly sensitive to the effects of DHT.

This is where gynecomastia comes in. It’s caused by an imbalance of sex hormones in breast tissue. Because finasteride blocks the conversion of testosterone to dihydrotestosterone, it can potentially increase the ratio of female hormones like estrogen to androgens, thereby causing gynecomastia.

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As mentioned, finasteride–induced gynecomastia is very rare. In fact, in a large trial of the drug taken for AGA at 1 milligram a day, gynecomastia wasn’t even listed as a side effect because participants showed no evidence of breast tenderness or enlargement.

That said, some cases of gynecomastia have been linked to finasteride. The FDA (U.S. Food and Drug Administration) pamphlet for Propecia®, a brand-name drug with finasteride as its active ingredient, now lists “breast tenderness and enlargement” as a potential adverse effect.

If you’re on the fence about finasteride because you’re worried about gynecomastia, here’s something to consider: Spironolactone, another hair loss medication commonly used to treat female pattern hair loss, isn’t recommended for men, as it’s a well-known cause of gynecomastia. The condition is actually the most commonly reported adverse reaction associated with the drug.

So, if gynecomastia were a common side effect of finasteride, based on what we know about spironolactone, it’s safe to assume it wouldn’t be recommended for male pattern baldness.

Knowing the symptoms and signs of gynecomastia can help you and your healthcare provider assess your situation.

Signs and symptoms of finasteride gynecomastia include:

  • A lump below the nipple

  • Areola enlargement or puffy nipples

  • Soreness in the chest in one or both breasts

  • Nipple discharge

  • Uneven or uniform breast growth

  • Swelling or tenderness of the nipples and breasts

Many men Google “does gyno from finasteride go away” and “how to prevent gyno on finasteride.” (We get it, gynecomastia is a lot to type.)

The good news is that if it’s caused by medication, finasteride is generally reversible once you stop taking whatever drug is causing it.

In one known case report of finasteride gynecomastia, a 19-year-old man developed unilateral gynecomastia (that means just on one side) after eight months on finasteride.

The condition resolved within four months of stopping the treatment and didn’t recur later when he started retaking finasteride at a reduced frequency.

The second case was a 43-year-old who experienced symptoms just 20 days into treatment. For this person, breast enlargement persisted after stopping medication.

In many cases, gynecomastia will resolve on its own after you stop taking the drug that’s causing it. If you don’t want to stop taking finasteride, your healthcare provider might recommend taking additional medications that can reduce gynecomastia symptoms.

These include:

  • Aromatase inhibitors

  • Androgens

  • Anti-estrogens (also called estrogen blockers)

In more extreme cases, some men may decide to get a mastectomy for gynecomastia. In a 2019 study, 1673 patients underwent surgery for gynecomastia, and 52 of them continued finasteride treatment post-surgery.

The study found no significant differences in postoperative complications or recurrence rates of gynecomastia between those who used finasteride and those who didn’t.

Most notably, gynecomastia didn’t return post-surgery for those who kept up with finasteride therapy. So if your gynecomastia is severe enough that you’re considering surgery, finasteride might still be a post-op option for treating hair loss.

Remember, if you stop taking finasteride, hair loss will eventually resume. For that reason, you may want to explore hair loss treatments.

If you’re worried about finasteride breast growth or have experienced gynecomastia in the past, you might be looking for alternative hair loss treatments.

Minoxidil

Minoxidil is a powerful hair loss ingredient that’s FDA-approved in its topical form specifically for male pattern baldness. Oral minoxidil is also sometimes used to treat AGA, though this is an off-label use (meaning it’s prescribed for something the FDA hasn’t approved it for).

You may be more familiar with Rogaine®, whose active ingredient is — you guessed it — minoxidil.

We offer minoxidil foam and minoxidil solution (a liquid). And if you prefer to take your medicine rather than apply it, we also have chewable minoxidil, which pairs the ingredient with other hair-loving nutrients like biotin and vitamin B6.

Topical Finasteride and Minoxidil Combo

Since topical finasteride doesn’t enter the bloodstream like a pill does, it’s very unlikely to cause gynecomastia. With that in mind, applying it directly to your scalp might be a good alternative to oral finasteride — even better if you combine it with minoxidil.

Our topical finasteride & minoxidil spray contains both ingredients. Research shows that using the two together is actually more effective than either alone.

Hair loss treatments, delivered

Worried about finasteride causing gynecomastia? Here are a few things to remember:

  • Finasteride gynecomastia is super rare. Adverse events are possible on most medications, including finasteride. While the side effects of finasteride vary, the incidence of gynecomastia is quite low. Some research notes that there are currently under 10 known cases.

  • Some have a higher risk of gynecomastia. If you’re wondering how to prevent gynecomastia while taking oral finasteride, the answer is a little complicated. There’s no special trick you can do to avoid it, but certain factors (like age, dosage, and thyroid issues) may increase the likelihood of this adverse effect.

  • Diagnosis can be tricky. Diagnosing gynecomastia requires a deep understanding of hormonal factors like estrogen, growth hormone (GH), and insulin-like growth factor (IGF-1), which all contribute to male breast growth. For this reason, it’s important to consult a medical provider with experience with the condition if you suspect gynecomastia.

Check out our range of hair loss treatments (which includes finasteride), or connect with a licensed healthcare provider online through our platform to learn more about the right treatments for you.

11 Sources

  1. ALDACTONE® (spironolactone) tablets for oral use. (1960). https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/012151s077lbl.pdf
  2. Bowman JD, et al. (2012). Drug-induced gynecomastia. https://pubmed.ncbi.nlm.nih.gov/23165798/
  3. Chen L, et al. (2019). The Efficacy and Safety of Finasteride Combined with Topical Minoxidil for Androgenetic Alopecia: A Systematic Review and Meta-analysis. https://cdn.mednet.co.il/2012/05/the-efficacy-and-safety-of-finasterideminoxidil.pdf
  4. Farkas HS, et al. (2024). Persistent Gynecomastia due to Short-term Low-dose Finasteride for Androgenetic Alopecia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11040274/
  5. Lee SG, et al. (2019). Influence of Postoperative Finasteride Therapy on Recurrence of Gynecomastia After Mastectomy in Men Taking Finasteride for Alopecia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6764051/
  6. Lorek K, et al. (2019). Clinical and Biochemical Phenotype of Adolescent Males with Gynecomastia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6878348/
  7. Mansouri P, et al. (2009). Finasteride-induced gynecomastia. https://ijdvl.com/finasteride-induced-gynecomastia/
  8. Natural HS, et al. (2014). Gynaecomastia--pathophysiology, diagnosis and treatment. https://pubmed.ncbi.nlm.nih.gov/25112235/
  9. PROPECIA® (finasteride) Tablets, 1 mg. (2010). https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/020788s018lbl.pdf
  10. Ramot Y, et al. (2009). Finasteride induced Gynecomastia: Case report and Review of the Literature. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929552/
  11. Swerdloff RS, et al. (2023). Gynecomastia: Etiology, Diagnosis, and Treatment. https://www.ncbi.nlm.nih.gov/books/NBK279105/
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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