what are the side effects of finasteride and post finasteride syndrome

What are the side effects of Finasteride? Post-Finasteride Syndrome

In our previous article, we explored the potential benefits of finasteride in treating male pattern hair loss, highlighting its ability to normalize hair loss and in many cases even stimulate regrowth. We have mentioned clinical trial outcomes and how finasteride function to treat male pattern hair loss.

However, concerns surrounding the drug’s side effects and post-finasteride syndrome have left many individuals skeptical about starting therapy. This article aims to address these misconceptions and shed light on the pros and cons of finasteride use for hair loss.

Many patients with male pattern baldness are hesitant about taking finasteride because they’ve heard rumors and read something about PFS and they’re scared of starting the therapy.

Many people don’t know how the 5ARIs work and they start taking the medicine expecting a miracle to happen. Unfortunately, most patients don’t experience regrowth in this short time and they stop taking the meds.

Finasteride For Hair Loss

Initially used to treat prostatic hyperplasia, finasteride received approval for male pattern hair loss treatment in 1997, providing over 25 years of experience with its use. Millions of men worldwide have benefited from the drug, with substantial positive outcomes reported treating MPB with finasteride at a dose of 1mg.

Reports of adverse effects and post finasteride syndrome (PFS) have caused fear among patients. A simple Google search about “post finasteride syndrome” will give hundreds of articles and videos regarding how some people are affected by finasteride side effects. And not all of it is false.

Finasteride has certain adverse effects since it suppresses the activity of the enzyme 5-alpha-reductase and lowers the level of DHT in the body. However, the number of individuals experiencing such side effects is relatively small.

The key is to understand how finasteride works and its dosage requirements to minimize risks and optimize results.

How does finasteride work for male pattern hair loss?

Finasteride works by inhibiting the enzyme 5-alpha-reductase, which converts testosterone into dihydrotestosterone (DHT). It is important to note that finasteride blocks enzyme activity and not hormones directly. This action leads to a decrease in DHT levels, contributing to hair loss stabilization and regrowth.

In short, finasteride is used for blocking enzyme activity and not blocking your hormones.

So why would people experience side effects if their hormones aren’t being altered? This is because DHT is a little stronger version of testosterone, and taking finasteride will progressively lower the amount of DHT since less testosterone is being converted to DHT due to decreasing enzyme activity in the body.

The medicine was originally designed for men with an enlarged prostate gland, not cancerous tumors, but for non-cancerous enlargement of the prostate. This condition was found to be caused by an overactive enzyme and excessive DHT in the prostate.

Interestingly, when scientists started using finasteride to treat men with enlarged prostates, they noticed that some balding men with the same condition experienced stabilization and even reversal of their hair loss. This accidental discovery led to the drug being used for treating hair loss, apart from its intended purpose. As a result, finasteride has been prescribed for both enlarged prostates and hair loss for a considerable period and is still in use today.

Finasteride dosage for hair loss

The standard recommended dose for hair loss is 1 milligram per day. However, studies have shown that a lower dosage of finasteride can be just as effective. Due to its prolonged presence in the system, taking the drug three times a week on average is a viable option. It’s crucial to consult a doctor to determine the most suitable dosage for individual needs.

The “correct dose” of finasteride can be a debated topic. The recommended dose of finasteride is 1 milligram per day for male pattern baldness (MPB). However, not every patient with MPB requires a daily 1mg dose because the medication remains in the body for an extended period.

What is the right finasteride dosage for hair loss?

You might wonder why not just take finasteride once a month if its impact lasts longer than 30 days. The reason is that our bodies continuously produce new enzymes, and finasteride works by reducing the activity of the 5-alpha-reductase enzyme. Many hair loss specialists recommend taking finasteride three times a week because it achieves the same stability as taking it every day.

Taking the correct dose of finasteride is crucial. Doctors often suggest that patients with male pattern hair loss who take a lower dose of finasteride usually experience fewer side effects compared to those taking higher doses. If you are taking 1mg of finasteride every day or every other day, you should not have any serious adverse effects.

The key point here is that people who experience side effects or post-finasteride syndromes are likely taking too much of the medication. By reducing the dosage while maintaining the same results without side effects, finasteride can be prescribed more frequently and safely used by many more men for hair loss without worrying about negative effects on their health.

Taking a higher dose of finasteride

The main goal of using finasteride is to stabilize hair loss without risking our health. To achieve this, it’s important to take the minimum effective dose of the drug that can stop hair loss without causing any side effects.

Unfortunately, some people misuse this medicine by taking excessive amounts, such as finasteride 5mg tablets per day for male pattern baldness, which is unnecessary and can lead to problems. This happens when individuals use the medication without proper guidance and consultation with a dermatologist.

Finasteride oral is available in both 5mg and 1mg pills. If you are experiencing hair loss, make sure you are not taking finasteride 5 mg tablets and that you adhere to the recommended dosage prescribed by your doctor, typically 1mg every day or 1mg every other day (EOD).

Some individuals mistakenly believe that taking higher doses of finasteride will yield faster and better results. However, this is not the case, and in fact, it may lead to serious side effects due to a sudden and significant decrease in DHT levels.

Most doctors advise a smaller dose of finasteride because it remains active in the body for longer than a day. Therefore, daily intake is unnecessary; the key is to lower DHT levels to a specific threshold, preventing further hair loss.

Before starting oral finasteride or any medication, it is essential to consult a doctor and obtain a proper diagnosis so that the doctor can recommend the appropriate dose for your condition.

Side Effects of Finasteride

Side effects of finasteride were already known when it was being used to treat the prostate before it was utilized for hair loss treatment.

When finasteride was prescribed at a five-milligram dose for prostate issues, around 5-8% of males reported experiencing decreased libido, which refers to a reduced sex drive, or difficulties in maintaining erections. These side effects were observed prior to its use for hair loss treatment.

Clinical trial of finasteride

In a clinical trial, researchers conducted a study with 2000 male participants divided into two groups of 1000 each. The doctors and participants were unaware of whether they were receiving finasteride or a placebo (a substance with no active ingredient).

During the year-long study, the participants were monitored, and they knew they would be asked about any potential sexual side effects.

At the end of the study, when the results were analyzed and the treatment groups were revealed, it was found that 1.8% of males on finasteride reported experiencing sexual side effects. Interestingly, and surprisingly, 1.3% of the group receiving the placebo (sugar) also reported sexual side effects.

The key takeaway from this study is that the psychological aspect plays a role. If participants believed they might experience side effects, they were more likely to report them, even if they were taking the placebo. The incidence of actual side effects from finasteride was minimal, especially when taking a lower dose, likely less than 1.8%.

Recovering from Finasteride Side Effects:

There are two groups of people who may experience side effects from finasteride. The first group consists of individuals who respond promptly, experiencing adverse effects within the first two weeks of starting the medication. These patients are highly sensitive to the drug, and their bodies struggle to adapt to the sudden change in DHT levels.

If someone experiences side effects within the initial two weeks of taking 1mg finasteride, they can simply stop using the medication, and in about two weeks, they should fully recover. Almost all patients who report adverse effects within the first two weeks of using finasteride find that their side effects resolve within two weeks of discontinuing the drug.

It typically takes about a week or two for the body to detox from the effects of finasteride and for DHT levels to return to balance.

Over the years, there have been no reports of anyone failing to recover from their side effects after stopping the medication.

The second group of people consists of those who do not experience side effects immediately but do so after taking the medication for an extended period. This delayed response can occur between four and eight months into therapy or possibly even longer and is often associated with those who have been taking finasteride daily.

What Happens If You Stop Taking Finasteride for Hair Loss?

Discontinuing finasteride use might lead to hair thinning and loss over time, as DHT levels return to normal. However, taking short breaks from the medication to allow excess finasteride to wash out of the system will not have significant negative consequences.

Post-Finasteride Syndrome

There are a few more uncommon adverse effects associated with the use of finasteride. Some individuals may experience “brain fog,” a term used to describe a feeling of mental haziness, where they may not think as clearly as they typically do. Additionally, some users may experience breast soreness or swelling of the scrotum. It’s important to note that these side effects are extremely rare.

However, it has been observed that patients who take finasteride in moderate dosages, typically three times per week, tend to have fewer difficulties and are highly successful in preventing further hair loss.

To minimize the risk of side effects, it is often recommended to take the medication in lower doses and adjust the frequency based on the individual’s response to treatment. As with any medication, it’s crucial to consult a healthcare professional before starting or making any changes to the dosage to ensure safety and effectiveness.


In conclusion, finasteride remains a highly effective treatment for male pattern hair loss. The key to a successful and side-effect-free experience lies in understanding proper dosage and frequency.

Consult with a healthcare professional for a more personalized and suitable hair loss regimen. When used correctly, finasteride can significantly improve hair loss conditions and offer hope to those seeking a reliable solution.

Written by Dr. Ahmed Mostaque

Dr. Ahmed is an associate professor of medicine. He has a bachelor’s degree in medicine from the Bangabandhu Sheikh Mujib Medical University Hospital. He also enjoys writing articles about health and well-being.

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