Propecia (Finasteride) Side Effects to Look Out For

Medical Disclaimer: Freebird provides general information, not medical advice. For any health or medical advice, consult a licensed healthcare professional

When you see your hairline retreat faster than your ex after a bad date, reaching for Propecia (finasteride) seems like a good move. But here's the thing, while over 80% of men see results with finasteride, they can come with some serious side effects.

I came across Propecia when my own hairline started playing hide and seek. What I found helped me decide to stick with clippers over pills. From annoying to life altering side effects and some that stick around after you stop taking the pill.

Join me as we dive deeper into the science behind Propecia and find out what it does to your body (some are serious), learn about combination treatments, and whether keeping your hair is worth the potential risks.

What is Propecia?

Propecia, or Finasteride, is an FDA-approved oral prescription drug for treating male pattern baldness. 

It works by blocking an enzyme that converts testosterone into DHT or dihydrotestosterone. DHT is a hormone that shrinks hair follicles and sends them into early retirement.

By lowering DHT levels, Propecia can help slow hair loss and sometimes promote hair growth.

Propecia is also prescribed for men with an enlarged prostate or benign prostatic hyperplasia.

Here's something you need to know: The FDA hasn't approved any topical version of finasteride since they lack the clinical trials needed for approval. Those topical sprays carry the same risks as the pills.

Merck and Co. sells finasteride tablets under the brand name Proscar.

The Science Behind Propecia

Propecia belongs to a class of drugs called 5-alpha reductase inhibitors. Think of 5-alpha reductase as the enzyme that turns testosterone into DHT. Finasteride blocks that enzyme, which means less DHT floating around your system.

DHT is the main culprit behind male pattern baldness. When you have too much of it, your hair follicles shrink over time until they stop producing visible hair. Block the DHT, and you slow down or sometimes reverse that process.

Several studies prove that Propecia works. In one study, 1,553 males with pattern hair loss were given oral finasteride therapy for two years and saw significant results. Another recent study shows that 80% of 450 men with pattern hair loss who took Propecia showed improvement in 12 months. These are solid numbers if you're trying to battle hair loss.

But here's where it gets tricky: Finasteride doesn't just affect your scalp and prostate. It works throughout your entire body, including your brain. And that's where many of the side effects come from.

Common Side Effects of Finasteride Tablets

Let's talk about what you might experience while taking finasteride. These are what show up often in clinical trials and real-world use:

Lower Libido

Decreased libido is a persistent sexual side effect of finasteride users. A 2011 study published in the Journal of Sexual Medicine showed 94% of 71 men tested reported lower libido after taking finasteride, with symptoms continuing after 3 months of stopping use. Why gamble your sex life?

Erectile Dysfunction

Erectile dysfunction is one of the most common finasteride side effects. We're talking about difficulty getting or maintaining an erection. In the same study from the Journal of Sexual Medicine we mentioned, 92% of the 71 men developed ED.

The frustrating part? A large study found that men who took finasteride longer were more likely to develop ED than those who took it for shorter periods.

Suicidal Thoughts

This is where things get darker.

Since sexual dysfunction is a common side effect of Propecia, more men get depressed and even have suicidal thoughts. A 2012 study in the Journal of Clinical Psychiatry showed that 44% of former finasteride users experienced suicidal thoughts versus 3% of men who never used Propecia.

Let that sink in for a second. We're talking about a hair loss drug that potentially triggers thoughts of ending your life. Dark stuff.

Finasteride Shedding

Some finasteride users may notice increased hair shedding during the first few months. This is a normal part of the hair cycle, where thinner hair makes way for newer and thicker hair growth.

Mild common side effects usually subside within a few days or a week. If they're severe or don't disappear, consult your healthcare professional.

Less Common Side Effects 

Some men also report:

• Pain in the testicles

• Unusual weight gain

• Depression

• Nipple discharge

• Breast pain

• Breast tenderness

• Decreased amount of semen

• Back pain

• Diarrhea

• Headache

• Stomach pain

• Dizziness

Is Propecia Safe To Use?

Generally, yes, Propecia is safe to use. It's one of two treatments for male pattern baldness that the FDA approves, the other being Rogaine (minoxidil).

If you're taking Finasteride to treat hair loss or BPH, you need to be aware of these important warnings:

Avoid Contact with Pregnant Women

Pregnant women should never handle crushed or broken finasteride tablets. The drug can be absorbed through the skin and cause birth defects in male babies. If contact occurs, wash the affected area immediately with soap and water, and then call a doctor.

Prostate Cancer Warning

While finasteride reduces overall prostate size and can help with BPH, it may increase the risk of developing aggressive, high-grade prostate cancer. Talk to your doctor about regular prostate cancer screenings.

Liver Disease Warning

If you have liver disease, your body may process this drug more slowly, which increases the risk of side effects. Your healthcare professional may give you low-dose Finasteride or ask you to avoid it altogether.

Male Infertility

Some men who use finasteride are unable to have children. The infertility appears reversible with the 1 mg dose, but having children may be negatively impacted by the 5 mg dose. If you're planning to have kids, talk to your doctor first.

How To Use Finasteride Safely?

If you decide to take finasteride, here's how to do it right.

Remember, your dose and form of taking Finasteride may vary and will depend on:

• Age

• Condition being treated

• Severity of condition

• Other medical conditions

• Reaction to the initial dose

You must take Finasteride as prescribed. If you take too much, you may experience adverse reactions like a skin rash, breast tenderness, decreased libido, ejaculation disorder, and erectile dysfunction..

If you miss a dose, don't take an extra dose to make up for the one you missed. Take the next dosage as usual. Larger doses won't improve results and may increase the risk of side effects.

If you're taking Finasteride for benign prostatic hyperplasia (BPH), you may experience an improvement in your condition, like improved urine flow and a lesser urge to urinate. On the other hand, if you're taking Finasteride for hair regrowth, you may notice slower hair loss than before.

Additional reminders when taking Finasteride:

• No crushing, cutting, or chewing of tablets

• Store finasteride at room temperature, preferably between 59°F and 86°F

• Keep away from sunlight and high temperatures

• Store in a cool and dry place

• Always carry your tablets with you when traveling

• Always have the original prescription labeled container to show airport personnel

• Don't leave tablets in your car's glove compartment

The Different Dosages of Finasteride

Finasteride is available in either a 1 mg or 5 mg dose. You may think the larger dose is more potent and more effective in hair loss treatment. This is not the case. Remember, Finasteride's other medical use is to lower symptoms of an enlarged prostate gland or benign prostatic hyperplasia.

If you have an enlarged prostate, you'll get the 5 mg dose. To treat male pattern baldness, 1 mg tablets are usually prescribed.

Serious side effects of Finasteride: When to call your doctor immediately

Call your doctor immediately if you experience side effects like a severe allergic reaction to Propecia. Here are other serious symptoms you should look out for:

• Depression

• Swelling in your tongue, lips, throat, or face

• Lumps of pain in your breast

• Nipple discharge

• Chills

• Cold sweats

• Confusion dizziness

• Trouble breathing

• Hives

Interactions With Other Medications

Finasteride has no major documented drug interactions, but always tell your doctor about every medication, supplement, and herbal product you're taking. Better safe than sorry.

Combination Therapy: Propecia and Rogaine

Did you know that combining finasteride with minoxidil produces significantly better results than using either drug alone? 

Why does this combo work so well? One acts as a DHT blocker (Propecia) and the other as a hair grower (Minoxidil).

The numbers are impressive:

A 2025 study of 502 men found that 92.4% achieved stable or improved outcomes with combined oral finasteride and minoxidil over 12 months. More than half (57.4%) showed marked improvements.

The best part? The side effects don't increase. You're still prone to the side effects of each drug, though, like sexual and mental health risks (finasteride) and unwanted hair growth (minoxidil).

The downside? You're committing to a lifetime regimen. Stop either medication, and your hair loss resumes within 12 months. Plus, you're doubling your monthly costs.

My Personal Decision

When I started looking for solutions for my male pattern hair loss, I came across Rogaine and Propecia, but after learning about the possible adverse effects, I had to decide. Keep my hair but risk sexual dysfunction, depression, and potentially permanent side effects? Or accept baldness and move on?

A full head of hair with a ton of side effects doesn't work for me. The stats looked good on paper but what's the use of having a full head of hair only to face severe problems like erectile dysfunction, depression, loss of sexual function, and prostate cancer?

A hair loss treatment with tons of persistent sexual dysfunction side effects is not for me.

However, if you have an enlarged prostate or benign prostatic hyperplasia, that's another story. Your doctor may prescribe Propecia to treat an enlarged prostate.

When I realized there was no cure for male pattern hair loss, I shaved my head and never looked back.

I've been sporting the buzz cut for more than a decade. A few years ago, I started a closer shave with my Freebird FlexSeries electric shaver. 

Head shaving has freed me from worrying about male pattern hair loss and the never-ending treatments that won't restore my hair fully. Shaving also makes me look younger and well-groomed.

But hey, your situation may be different.

The Bottom Line

Propecia works. The science is solid. 88% of men see slower hair loss, and 66% experience new growth. Combine it with minoxidil, and the number jumps to 94%. Those are real results.

But those results come with real risks. Sexual dysfunction. Depression. Potential long-term effects that might not go away even after you stop. But for men with BPH, the drug can be life-changing in a positive way.

Only you can decide if the trade-off is worth it. Just make sure you're going in with your eyes open.

If the side effects are a red flag for you, you can always choose to go bald and shave your head like me.

For tips on how to shave your head, click on the link and look good doing it.

You'll also need a reliable and safe head shaver to do the job. I recommend the FlexSeries.

FAQs

How Long Do Propecia Side Effects Last After Stopping?

Most side effects reverse within 12 months after stopping Propecia. Your hair loss will resume at its natural pace, and DHT levels return to normal. Some men report that sexual side effects like reduced libido and ejaculation problems persist beyond a year, which is why post-finasteride syndrome remains controversial.

How Long Do Finasteride Side Effects Last?

They may last anywhere from a few days to a few weeks. If you're worried or if they seem severe, visit your doctor immediately. Some men have shared that persistent sexual side effects can be permanent even after stopping taking Finasteride.

How Common are Propecia Side Effects?

The bad news is that Propecia side effects are pretty common. While over 90% of men who take Propecia tablets notice improvement and 66% experience renewed hair growth, sexual dysfunction is a commonly reported issue.

What are the Long-Term Side Effects of Propecia?

Some men have shared that sexual dysfunction side effects are permanent. Some reported that erectile dysfunction continued even after stopping taking Finasteride.

Is Propecia Worth It?

The numbers show that Propecia works for hair loss. The only question is, do you value hair growth over the potential side effects of taking finasteride therapy?

Which is worse? Being bald or risking erectile dysfunction, decreased libido, enlarged prostate, ejaculation disorder, male breast cancer, skin rash, male infertility, and depression, to name a few side effects of taking Finasteride.

If you experience an allergic reaction to Propecia, it's better to stop the treatment immediately.

Does Propecia Lower Testosterone?

No, Propecia doesn't lower testosterone, but it decreases the level of DHT, or dihydrotestosterone by 70%.

How Do You Reduce the Side Effects of Finasteride?

Here are a few ways to reduce the side effects of Propecia. Follow the prescribed dosage, consult a licensed healthcare professional before treatment, take a lower dosage, maintain a healthy weight, exercise, and eat a balanced diet.

Is it Safe to Take Finasteride Daily?

Yes, Finasteride is generally considered safe to take daily, specifically in the prescribed dosages for treating male pattern baldness or BPH (benign prostatic hyperplasia).