Reviewed by Kristin Hall, FNP
Written by Our Editorial Team
The science is real: Finasteride is a safe and effective way for men to treat hair loss — as long as they’re mindful of side effects, drug interactions and other risks.
Clinical trials and other research show that finasteride (also known as Propecia®) is proven to treat male pattern baldness (androgenetic alopecia). It works by inhibiting an enzyme called 5-alpha reductase and reducing a key compound in the reduction of hair growth: dihydrotestosterone, also known as DHT.
Finasteride is an oral and topical reductase inhibitor used daily, either in the form of finasteride tablets or a topical solution. When used correctly, it can reduce DHT levels by more than 90 percent in some cases — slowing the progress of male pattern hair loss.
But that reduction is not without risks. One of the primary sources of risk is interactions with other medications.
Worried your heart disease, liver disease or other medications might bring unforeseen problems when crossed with finasteride? We’ve got you covered.
Below we’ll go over drug interactions, side effects, medical conditions and other risks associated with finasteride and provide tips on how to stay safe when using it.
Let’s dive in so you can get back to handling your hair growth priorities.
Let’s get the good news out of the way early on: According to the FDA (U.S. Food and Drug Administration), there are no major interactions associated with finasteride you need to worry about.
The FDA’s drug information guide for finasteride says that “no drug interactions of clinical importance have been identified.” That’s really good news, especially for anyone who’s listened to the auctioneer barking side effect warnings at the end of an antidepressant commercial.
The primary concern when using finasteride alongside other medications is accidentally causing unusually high concentrations of the drug in your blood, which can lead to more serious side effects.
Those side effects may include:
Skin irritation in the topical formulation
Sexual side effects like reduced libido
While sexual side effects can occur, some of the claims are over the top and would be considered part of the myths and facts about finasteride side effects. The truth is that in clinical studies, less than 2 percent of finasteride users experienced erectile dysfunction, a decrease in libido or an ejaculation disorder.
If you’re one of the few people who experience side effects as a result of taking finasteride, contact your healthcare provider for further instructions.
Oh, and here’s a little extra good news: Some drugs can compound the positive effects of finasteride, including minoxidil, commonly known as Rogaine®.
Minoxidil isn’t a DHT blocker. Instead, it works by increasing blood flow to the parts of your body that need it most.
Since it doesn’t have the same mechanism of action as finasteride, using the two together can increase the effectiveness of both compounds in fighting and even potentially reversing the effects of hair loss.
Now for the bad news: Finasteride may not play well with certain health conditions.
The first two categories that might be a red flag for finasteride are urologic and liver issues. If a patient has known liver issues or urinary issues, they may not be able to take finasteride safely — any conditions or medications related to these issues should be shared with a healthcare provider before taking finasteride.
There’s also a potential relationship to breast cancer for both men and women that’s been noted in research, as well as breastfeeding risks that led to nipple discharge in infants.
We should note Propecia is not FDA-approved for treatment in women. Also, finasteride is contraindicated in pregnant women, so those who are pregnant or trying to conceive should avoid any contact with the tablets.
Here’s the scariest and simultaneously rarest concern: A slightly increased risk of high-grade prostate cancer. Prostate cancer and prostate enlargement have been associated with 5-alpha reductase inhibitors like dutasteride.
“I tried several different options before but Hims combined approach of all four methods by far created the best results.”
“Hims has been the greatest confidence boost, no more bald jokes! I look and feel so much younger!”
“When I show my barber my progress, he is always in disbelief. I have to recommend Hims to any guy who’s experiencing thinning.”
“Cost effective and affordable. My hair keeps growing thicker, fuller, and at a fast rate.”
“I noticed a huge change in the overall health and fullness of my hairline.”
“Now after 5 months I’m able to style waves first time in 10 years!”
“I decided to jump right in and I'm so glad I did. I definitely feel ten years younger!”
“In just as little over two and half months, I can really see the difference in thickness and in color.”
“4-months strong and my confidence boosted back up to 100% using Hims, future me really does thank me.”
“I’m a 34-year-old father of two and have been using Hims for over a year now. My hair is back to what it was in my mid-twenties.”
These issues have also been associated with finasteride in research, but that was at a dosage of 5 milligrams, which is significantly higher than the recommended dose of 1 milligram.
It’s also worth noting that a small number of men who take finasteride continue to experience some side effects even after cessation of treatment. This has been occasionally referred to as post-finasteride syndrome.
Generally speaking, you should share all types of medications you’re taking with a healthcare provider to get the appropriate medical advice to stay safe. A single dose of finasteride could have adverse interactions with anything you’re taking, whether it’s over-the-counter supplements, FDA-approved prescription drugs or anything in between.
Better safe than sorry.
Generic for Rogaine®, this FDA-approved over-the-counter version of topical minoxidil is used for regrowth on the crown of the head.
This is the FDA-approved dynamic duo. When used together, men saw better results in clinical trials compared to using either alone.
If you’re looking for something effective but don’t want too many steps in your routine, this once-a-day pill could be right for you.
Clinically proven to regrow hair in 3-6 months, no pills required.
Trying to nail down the big picture on how to stay safe? We’ve got some tips below.
But first, let us leave you with some parting bullet points:
Finasteride is available in both generic form and under several brand names like Propecia. It also comes as a medication for benign prostatic hyperplasia (enlarged prostate) in the form of Proscar.
It’s considered overall very safe and effective to use.
Finasteride can be used in conjunction with other treatments, including chemical and clinical therapies and lifestyle changes. It can also be used alongside minoxidil.
Per finasteride’s FDA label, there are no major drug interactions associated with this drug.
You should consult your healthcare provider before using finasteride and clarify what, if any, medications you’re taking that might cause problematic interactions.
Here’s how to stay safe when taking finasteride:
Only take your instructed finasteride dosage — excess finasteride can increase your risk of side effects.
You may experience certain withdrawal symptoms when stopping finasteride — a condition known as post-finasteride syndrome.
While topical finasteride is sold over the counter, oral finasteride requires a prescription.