Medically reviewed by Katelyn Hagerty, FNP
Written by Our Editorial Team
Last updated 10/11/2021
Finasteride, which is sold as a generic and under the brand name Propecia®, is one of the most popular medications on the market for treating and preventing male pattern baldness.
Like all medications, finasteride can cause side effects. If you’ve searched online for information about these side effects, you may have come across mentions of long-lasting, persistent issues that are referred to as post-finasteride syndrome, or PFS.
Post-finasteride syndrome is a controversial condition. Although a very small percentage of men claim to develop post-finasteride syndrome symptoms after taking finasteride, PFS isn’t officially recognized by most of the medical community.
Below, we’ve looked into reports of post-finasteride syndrome, as well as the latest research on this rare reported side effect of finasteride use.
We’ve explained what post-finasteride syndrome is, the symptoms that are associated with PFS, as well as the potential treatment options for men who have issues after using finasteride.
Finally, we’ve explained your options for treating and preventing hair loss if you’re worried about developing post-finasteride syndrome.
Finasteride is a 5-alpha reductase inhibitor that’s used to treat androgenetic alopecia (a clinical term for male pattern baldness) and benign prostatic hyperplasia (non-cancerous growth of the prostate gland). It’s sold under the brand names Propecia and Proscar®.
As a 5-alpha reductase inhibitor, finasteride works by inhibiting the effects of the enzyme that’s responsible for converting testosterone into dihydrotestosterone (DHT).
Male pattern baldness develops when DHT binds to receptors in the scalp and causes the hair follicles to miniaturize. We’ve explained this process and its effects on your hair in our guide to DHT and male hair loss.
Research also suggests that DHT can stimulate the growth of cells in the prostate, contributing to benign prostatic hyperplasia.
By blocking the conversion of testosterone to DHT, finasteride drastically reduces DHT levels in the body.
Research has shown that finasteride cuts DHT levels in the prostate by upwards of 90 percent, and by more than 70 percent in the bloodstream.
This reduction in DHT greatly reduces prostate growth and either slows down, stops or reverses hair loss caused by male pattern baldness.
Post-finasteride syndrome is a term that’s used to describe a range of persistent symptoms that occur in a small percentage of men who use the medication finasteride.
According to the Post-Finasteride Syndrome Foundation, a 501(c)(3) nonprofit corporation that’s dedicated to raising funds for research into post-finasteride syndrome, men with post-finasteride syndrome have reported the following physical symptoms:
Sexual dysfunction, including a decreased sex drive or complete loss of libido
Erectile dysfunction (ED)
Loss of “morning wood” and spontaneous erections
Peyronie's disease (growth of scar tissue in the penis)
Shrinkage and numbness of the penis
Sexual anhedonia, or loss of pleasure from sexual stimulation and/or arousal
Ejaculation disorders, such as reduced ejaculatory volume and force
Shrinkage and numbness of the testes
Gynecomastia, or male breast growth and sensitivity
Chronic fatigue and lack of energy and enthusiasm
Muscle pain, weakness, cramps, stiffness and twitching
Rhabdomyolysis (rapid breakdown of damaged or injured skeletal muscle)
Elevated creatine kinase levels
Dry, thinning skin and decreased production of sebum (an oily substance that products your skin)
Melasma (a skin condition that involves patches of dark, discolored skin)
Tinnitus (ringing in the ears)
Lipoatrophy (loss of fat tissue in specific areas of the body)
Increased body mass index (BMI) and fat deposition
Reduced HDL cholesterol levels, raised triglycerides and fasting glucose
Increased rheumatoid factor (proteins produced by the immune system)
Decreased body temperature
Optic neuropathy (damage to the optic nerve inside the eyes)
Ocular toxicity (drug-induced damage to the eyes)
Retinopathy (disease of the retina)
Post-finasteride syndrome is also said to involve mental and neurological symptoms. According to the Post-Finasteride Syndrome Foundation, these may include:
Reduced memory and difficulty recalling information
Impaired ability to solve problems and comprehend information
General cognitive impairment and slowed thought processes
Depression, anxiety and/or suicidal ideation
Anhedonia (inability to feel pleasure) and emotional flatness
Insomnia (difficulty falling asleep or staying asleep)
Obstructive sleep apnea
According to the Post-Finasteride Syndrome Foundation, post-finasteride syndrome may result in an increased risk of suicide attempts.
Unlike regular finasteride side effects, post-finasteride syndrome is designed as persistent side effects from finasteride that can continue after the medication is discontinued. Some men with PFS report symptoms that last for years after stopping finasteride.
Many websites that discuss post-finasteride syndrome describe it as a lifelong condition with no treatments or cures.
For example, according to the Post-Finasteride Syndrome Foundation’s FAQs page, there is “no known cure” for post-finasteride syndrome, nor are there any known scientific reports of patients with post-finasteride syndrome returning to full health.
Based on the symptoms and descriptions provided online, post-finasteride syndrome can sound like a severe, untreatable condition.
This is understandably concerning for many men with male pattern baldness or benign prostatic hyperplasia who are considering finasteride as a treatment.
After all, if the long-term side effects of finasteride are potentially much worse than going bald, why use it in the first place?
When it comes to the side effects of medication, especially severe ones, it’s important to look at data objectively.
Although the symptoms of post-finasteride syndrome are alarming, it’s important to keep in mind that they are incredibly rare, even in long-term finasteride users. This is especially true once the placebo and nocebo effects are taken into consideration.
Like other medications, finasteride went through several large-scale clinical trials before it finally received approval from the FDA.
In these trials, researchers found that finasteride did cause several of the side effects mentioned above, including decreased libido, erectile dysfunction and ejaculation disorder.
However, only a very small percentage of men who used finasteride at the 1mg daily dose that’s used to treat hair loss experienced any of these side effects.
For example, in a one-year trial, men with male pattern baldness who were treated with 1mg of finasteride per day reported the following side effects:
Decreased libido (reported by 1.8 percent of men)
Erectile dysfunction (reported by 1.3 percent of men)
Ejaculation disorder (reported by 1.2 percent of men)
At first glance, this may look concerning. However, many men who were treated with a placebo medication also reported the same side effects:
1.3 percent of men who received the placebo reported decreased libido
0.7 percent of men who received the placebo reported erectile dysfunction
0.7 percent of men who received the placebo reported ejaculation disorder
A similar trend occurred in trials of Proscar, a 5mg form of finasteride that’s used to treat benign prostatic hyperplasia.
After using finasteride at a 5mg daily dose for one year, men reported the following side effects:
Erectile dysfunction (reported by 8.1 percent of men)
Decreased ilbido (reported by 6.4 percent of men)
Decreased ejaculatory volume (reported by 3.7 percent of men)
Ejaculation disorder (reported by 0.8 percent of men)
Gynecomastia, or male breast enlargement (reported by 0.5 percent of men)
Breast tenderness (reported by 0.4 percent of men)
Like in the above trial, men placed in the control group received a non-therapeutic placebo. The men that received the placebo reported similar side effects:
3.7 percent of men who received the placebo reported erectile dysfunction
3.4 percent of men who received the placebo reported decreased libido
0.8 percent of men who received the placebo reported decreased ejaculatory volume
The other side effects, such as ejaculation disorder, breast enlargement and breast tenderness, were only reported by 0.1 percent of men who received the non-therapeutic placebo.
Over the long term, the differences in side effect rate between the men who received finasteride and the men who received the placebo became significantly smaller. In some cases, there was no difference in side effect rates between the two treatments.
For example, during the second, third and fourth years of the trial, 5.1 percent of men who used finasteride 5mg reported experiencing erectile dysfunction. Among the men who used the placebo, 5.1 percent also reported experiencing erectile dysfunction.
The same pattern occurred with decreased libido, with 2.6 percent of finasteride users and 2.6 percent of placebo users both reporting this side effect.
Now, this doesn’t mean that finasteride itself can’t cause side effects. It can and does, although they typically aren’t common. However, it does raise questions about the theory that finasteride has the potential to cause lasting, long-term, severe side effects.
Within the medical community, there’s debate about whether post-finasteride syndrome is a real medical condition or something that’s largely psychological.
Most of the research used to support the idea of post-finasteride syndrome is low quality, with issues such as selection bias believed to affect results. As a result of this, most medical bodies do not officially recognize post-finasteride syndrome as a medical condition.
Experts believe that the symptoms commonly described as post-finasteride syndrome could be caused by several different factors.
The first of these is the nocebo effect. This is a psychological phenomenon in which a person’s negative expectations about a specific medication or procedure may cause them to experience a negative symptom.
For example, if a person is aware that a medication can cause headaches, they might become more likely to report experiencing a headache after using the medication.
This issue can have a serious impact on a person’s risk of experiencing side effects after taking medication, as healthcare providers are required to inform their patients about the potential side effects of medication as part of the treatment process.
While this may sound unusual, research backs it up, and even shows that it’s a specific problem for men who use finasteride.
In a small study published in the Journal of Sexual Medicine in 2007, men with benign prostatic hyperplasia were divided into two groups and treated with finasteride.
The men in one group were informed that they would use finasteride and told about the sexual side effects associated with the medication. The men in the other group were not told that they would use finasteride and did not receive a briefing on potential side effects.
The researchers found that the men who were informed about sexual side effects were around three times more likely to report experiencing ED, decreased libido or ejaculation disorders.
In short, being aware that finasteride may cause sexual side effects is associated with a higher risk of actually experiencing these side effects.
A second factor that may explain the symptoms of post-finasteride syndrome is existing mental illness.
Research has found that men who develop PFS generally don’t show signs of reduced 5-alpha levels or androgen deficiency, but do show symptoms similar to those in people diagnosed with depression.
A third factor is that a lot of the problems commonly described as symptoms of post-finasteride syndrome are common in middle-aged and older men, particularly men in the age group that is most likely to develop noticeable male pattern baldness.
Some research suggests that more than 50 percent of men in will experience some form of hair loss by the time they hit 50 years old.
Many men begin to develop sexual performance issues in middle age. For example, the rate of erectile dysfunction increases from just over eight percent for men in their 40s to more than 77 percent for men aged 75 or older.
There’s also a link between aging and a decline in testosterone levels. Since testosterone is an important hormone for sexual desire and function, this could cause a reduction in libido.
Researchers have theorized that the reported symptoms of post-finasteride syndrome may not be caused by finasteride itself, but just incidentally associated with finasteride use.
Overall, although there are lots of incidental reports of post-finasteride syndrome online and in popular media, there isn’t very much in the way of high quality scientific evidence to support its existence, at least not like there is for other medical conditions.
However, we may soon see more data. According to the National Institutes of Health, scientific research is underway to “better understand the effects of 5-alpha reductase inhibitor drugs” like finasteride.
As more studies are conducted, we may learn more about the possible link between finasteride and the reports of various long-term symptoms.
Although research overwhelmingly shows that finasteride is safe and effective, many guys have understandable concerns about using finasteride to treat pattern hair loss.
Currently, finasteride is the most effective option available for treating hair loss. However, it’s still possible to take action and reduce the severity of your hair loss without using finasteride.
Below, we’ve shared methods that you can use to treat and prevent male pattern baldness while minimizing your risk of post-finasteride surgery.
One way to treat your hair loss without using finasteride is to use non-prescription treatments for hair loss, such as minoxidil, hair loss shampoo and hair growth vitamins.
Minoxidil is a topical medication for treating hair loss. It’s available as a liquid and as a foam and is applied directly to the areas of your scalp affected by male pattern baldness.
Minoxidil doesn’t block DHT. However, it can shift hair follicles into the anagen, or growth, phase of the hair growth cycle, which stimulates growth. It also improves blood flow to the scalp, which may help to supply your hair follicles with extra nutrients.
As for hair loss shampoos, many include ingredients such as ketoconazole and saw palmetto to block DHT at the scalp level.
For example, our Hair Thickening Shampoo features saw palmetto to target DHT and prevent it from damaging your hair follicles.
Although vitamins don’t play a role in preventing male pattern baldness, many vitamins are vital for proper hair growth. Our Biotin Gummy Vitamins are formulated specifically for healthier hair, skin and nails.
If you’re worried about side effects from oral finasteride, you may want to look into using topical finasteride to treat your hair loss.
Topical finasteride works at the scalp level rather than systemically. Research suggests that it’s effective at treating hair loss and less likely to cause sexual side effects than finasteride taken orally.
We offer a combination Topical Finasteride & Minoxidil Spray that allows you to get the benefits of finasteride and minoxidil in a single medication.
Finally, another way to treat male pattern baldness without using finasteride is via hair transplant surgery.
This type of procedure involves removing DHT-resistant hair follicles from a donor area, such as the back of your scalp, then transplanting the grafted hairs to your hairline, crown or other areas affected by male pattern baldness.
Hair transplant surgery provides permanent results, but it can be costly. You may need to have multiple procedures if your hair loss worsens.
It’s also important to choose an experienced hair transplant surgeon to make sure you get satisfying, natural-looking results.
It’s also worth noting that in practice, most hair transplantation surgery patients are treated with finasteride before and after the procedure.
Post-finasteride syndrome is a term that’s used to refer to a range of symptoms associated with the use of finasteride as a treatment for hair loss and benign prostatic hyperplasia.
Although finasteride can cause adverse effects, there currently isn’t any high quality evidence to show that these continue over the long term.
In fact, most evidence shows that side effects from finasteride become less common the longer the medication is taken.
In general, side effects from finasteride are rare, with only a small percentage of men affected at the typical finasteride dosage used to treat hair loss.
If you’re concerned about post-finasteride syndrome, sexual symptoms or other side effects, it’s important to discuss them with your healthcare provider before using finasteride.
Alternatively, you can use other treatments, such as those available in our Non-Prescription Hair Loss Kit, to treat male pattern baldness without taking oral finasteride.
Insider tips, early access and more.