what are the side effects of finasteride and post finasteride syndrome

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

In our last piece, we discussed finasteride and how it might help people suffering from male pattern hair loss. We talked through some of the clinical trial outcomes and how finasteride can normalize male pattern hair loss and, in some cases, even grow back hair.

We’ve also briefly mentioned how finasteride works by converting some of your body’s testosterone into the hormone dihydrotestosterone, or DHT. In this post, we will examine the side effects of finasteride, which is an extremely significant aspect of this drug. Many people are skeptical about finasteride because of reports regarding adverse effects and post-finasteride syndrome.

A lot of patients with male pattern baldness are hesitant about taking finasteride because they’ve heard rumors and read too much about it and they’re scared of starting the therapy. Secondly, many people don’t know how the 5ARIs work.  and they just start the medication expecting something magical to happen. And when they don’t see any regrowth in this short time, they stop taking the meds because they don’t know this has to be long-term.

So why don’t we sort of unpack that a little bit and go through the implications of taking finasteride and what are the pros and cons from that perspective?

Finasteride For Hair Loss

Finasteride was first introduced as a treatment for prostatic hyperplasia but later in 1997, it received approval as a treatment for male pattern hair loss. So we’ve had over 25 years of experience in treating MPB with finasteride at a dose of 1mg.

To date, millions of men throughout the world have taken finasteride and they have seen some very good results with this drug. We now have a lot of information about what the drug can do and how it can be used to treat male hair loss.

Unfortunately, there are some misconceptions concerning finasteride and its negative effects that scare patients. You may look up “post-finasteride syndrome” and get 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 finasteride side effects is relatively small.

So let’s try to debunk the misconception surrounding finasteride and the side effects of this drug.

How does finasteride work for male pattern hair loss?

Again, as stated in the last article, finasteride works by inhibiting the enzyme, hence it is an enzyme blocker rather than a DHT blocker. However, it does lower the quantity of DHT in the body because it suppresses part of the enzyme activity that prevents some of the conversion of testosterone to DHT. In that scenario, the DHT level goes down and the testosterone level goes up.

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? We suppose 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.

So, how did finasteride come about? The medicine was actually designed for people who had enlargement of the prostate gland, not malignant tumors, but non-cancerous enlargement of the prostate in males, which they discovered was similarly a result of overactivity of the enzyme and too much DHT in the prostate.

So when scientists began using finasteride to treat patients with enlarged prostates, they were surprised to find that some of these balding men with enlarged prostates began to stabilize and reverse their hair loss. As a result, it was an accidental discovery that proved to be useful for hair loss. As a result, the drug is being used for purposes other than treating hair loss. It has been used for a long time and continues to be prescribed for patients with enlarged prostates.

Finasteride dosage for hair loss

So, when we were trying finasteride for hair, we realized that you didn’t have to use the same dose. For example, males using finasteride for an enlarged prostate should take a five-milligram pill every day. But for hair, the suggested amount is 1 milligram of fin, and the rationale for that is that if you monitor the response curve vs the dose curve, it kind of flattens out at approximately one, which implies that more isn’t better. A milligram is effective to treat male pattern baldness.

Now, this might be a little bit controversial when we talk about the “correct dose” of finasteride because the recommended dose on the packet says 1 milligram per day. In other words, you’re supposed to take a 1mg tablet of finasteride every day for MPB. You can certainly do so, and it is okay, although many individuals do not need to take a milligram every day. Why? Because the medicine stays in the system for far longer than a day.

If we return to the idea that the response occurs in the hair follicle, it is not the amount in the blood that is important, but the amount in the skin tissue. A finasteride dose lasts at least 30 days inside the skin. As a result, we don’t need to take fin every day. So, basically, you can take finasteride three times a week on average.

What is the right finasteride dosage for hair loss?

Now you might ask, why not just take finasteride once a month if the impact lasts longer than 30 days?

Our bodies, on the other hand, are constantly producing new enzymes. So what finasteride does is reduce the activity of the 5-alpha-reductase enzyme. Many hair loss specialists recommend this dosage plan since the outcomes are the same in terms of achieving stability compared to those who take finasteride every day.

Making sure you are taking the correct dose is very important. Many doctors suggest that patients with male pattern hair loss who take a lower dose of finasteride usually don’t have any side effects compared to others who are taking finasteride at higher doses. So if you are taking 1mg of finasteride every day or every other day you should not have any serious adverse effects from the drug.

So the key point here is people who are experiencing side effects from finasteride or suffering from post-finasteride syndromes are having problems because they’re taking too much of it.

And this is significant because if we can reduce the amount and yet get the same result without experiencing any side effects, then finasteride will be prescribed more frequently and used by many more men without the worry of negative effects or endangering their own health.

Taking a higher dose of finasteride

The goal with finasteride is to stabilize hair loss without risking health. So we need to take the least amount of drugs we can put in our system that will stop hair loss without any side effects.

Some people take finasteride five milligrams per day for male pattern baldness, which is excessive. And this is occasionally an issue since people use finasteride without understanding the proper amount for the therapy, and they buy their medications from wherever they can without consulting a dermatologist.

There are 5mg and 1mg pills available for finasteride. If you are suffering from hair loss make sure you are not taking the 5mg pill and you are not exceeding the suggested amount prescribed by your doctor. It’s usually 1mg every day, or 1mg finasteride EOD.

Some patients with balding believe that taking more or higher doses of finasteride will work faster and produce better results. The fact is that a high dose of fin will not improve your outcomes and will most likely cause serious side effects due to the drastic fall in DHT.

Most doctors recommend taking a small dose of finasteride because it lasts longer than a day in the system. You don’t need to take it on a daily basis. You just need enough to lower the DHT levels to that threshold level so that it doesn’t cause progression of the hair loss.

However, before starting the medication, you should see a doctor and get a diagnosis so that your doctor may recommend an appropriate dose for you.

Just to summarize, the lowest dose (1mg EOD) that will give us the expected outcome without any side effects is recommended.

Side Effects of Finasteride

And here’s the strange thing: we knew what the side effect of finasteride was since it was used to treat the prostate before it was used to treat hair. About 5-8% of males using finasteride at a five-milligram dose reported decreased libido, which is another word for sex drive or difficulty maintaining erections.

Clinical trial of finasteride

In the initial experiment, doctors investigated the impact of finasteride on 2000 males divided into two groups of 1000. Neither the doctor nor the patient knew whether they were taking finasteride or sugar, which we term a placebo since it has no active ingredient.

There are 1000 guys on finasteride and 1000 men on sugar. Neither the physicians nor the participants knew the medications they were taking, and they were monitored for nearly a year. However, the participants were aware that they would be asked about sexual adverse effects.

So, at the end of the year, when they analyzed the findings and opened up the study to see who was taking what, they discovered that 1.8% of males on finasteride had reported sexual side effects.

And it was probably a reasonable figure since it might be greater if you took five milligrams, but very interestingly, and perhaps shockingly, 1.3% of the sugar group complained of sexual side effects. So, basically, the key takeaway here is that if you believe you’re going to have the side effect, you probably will.

The way psychology works in the brain is that if you know it’s possible and really expect it to happen, you can probably convince yourself and make it happen, but the incidence of side effects is minimal.

When you are taking finasteride on a lower dose it’s probably less than 1.8% of patients who are having side effects.

Recovering from finasteride side effects

There are two groups of people that react by experiencing side effects. Some people respond promptly, which means they experience adverse effects within the first two weeks. This group of patients is extremely sensitive to the medication, and their bodies are unable to adapt to the abrupt change in DHT levels.

If you have any side effects within two weeks of starting finasteride, simply discontinue the medication and you will recover in about two weeks. Almost every patient who reports adverse effects within the first two weeks of using 1mg finasteride recovers within two weeks of discontinuing the medication. It takes about a week or two for your body to detox from the effect of finasteride and to balance your DHT level.

Throughout the years we haven’t seen anyone who didn’t recover from their side effects after stopping the medications

The second group consists of those who do not suffer side effects right away but do so after taking the medication for an extended period of time. This is a delayed response.

So there are patients who experience side effects between four and eight months, or perhaps even longer, into therapy. And that’s most likely because they’ve been taking it every day.

How Long Does it Stay in Your System?

Each 1mg pill of finasteride might stay in your system for up to 30 days. So it’s probably building up and piling up in your system until you start experiencing adverse effects from the medicine.

If you experience any side effects after taking the pills for months, you should stop the medication and wait for your system to recover. People who have been taking finasteride for a long time may take a little longer to recover since the medicine remains in the system for a long time.

So don’t be surprised in that scenario, whether it took two or three months for people to recover. And that’s normal. The guy and I’ve never had a single patient in 20 years that did not recover after they stopped their medication.

So if you’re someone that gets it later on, don’t get tensed about it. You can still use the medicine, just a more customized dose. So there are two ways you can reduce your intake, you either lower the dose or you can lower the frequency.

You can even take a month off from the medicine whenever you want. Because you know it’s going to hang around for a month and that’s going to do no harm. So stopping for one or two months is not going to harm you in the long run.

What Happens If You Stop Taking Finasteride for Hair Loss?

We often get asked, “What happens if you stop taking finasteride?” or “Am I going to lose hair again if I stop taking finasteride?”

Well, the answer is both yes and no. It depends on how long you intend to be on a break. If you stop taking finasteride and decide to discontinue the medicine, your hair will begin to thin and fall out again eventually after a few months. Once your DHT level becomes normal again, you will start noticing hair fall.

But if you are stopping for a short period of time, just to let the excess wash out of the system, you’re going to be fine.

Post-Finasteride Syndrome

There are a few more unusual adverse effects of using finasteride. One of the less frequent side effects that some individuals experience is brain fog, which means they don’t feel like they’re thinking as clearly as they should. They may experience breast soreness. They can have scrotum swelling, although these are extremely rare adverse effects.

Patients who take finasteride on moderate dosages, usually three times per week, have no difficulties and are extremely successful at preventing further hair loss.


In conclusion, finasteride is an excellent treatment for hair loss and is unquestionably the cornerstone of treatment for us in attempting to stabilize male pattern hair loss, but we also know that it is not without its drawbacks, but only when it’s taken in a higher or abnormal dose.

So if you are experiencing any side effects you’re probably on a higher dose of finasteride or you are taking it too frequently. Make sure to consult a doctor before you start taking finasteride to make sure you have the proper hair loss regimen.

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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