Dutasteride: A New Weapon Against Baldness?

You may have noticed that usually on Andro Genetic the drugs discussed are those approved for the treatment of androgenetic alopecia , while dutasteride is not yet. This is not only in Italy, but not even in Europe and the United States, where both the American FDA and the European EMA have granted authorization only for the treatment of benign prostatic hyperplasia (BPH).

So, why are we talking about dutasteride? The answer is quite simple: it is linked to the numerous requests received from our readers. Furthermore, by studying this drug in depth to prepare the article you are reading, I discovered that dutasteride has been approved for the treatment of androgenetic alopecia in South Korea since 2009 and, since September 2015, also in Japan .

Therefore, in my opinion, it deserves to be considered among the possible pharmacological remedies against male pattern baldness.

General information

Patented in 1996 by GlaxoSmithKline (GSK) and marketed under the name Avodart , dutasteride was created, as already mentioned, for the treatment of symptoms related to benign prostatic hyperplasia (BPH) .

How does it work?

Dutasteride is an inhibitor of the enzyme 5-alpha reductase , which is responsible for converting the male hormone testosterone into dihydrotestosterone (DHT) . The drug therefore reduces the production of DHT, which is known to be a major cause of BPH.

Unlike finasteride , which only acts on isoform 2 of the enzyme, dutasteride is a second-generation inhibitor that blocks both isoforms 1 and 2 of 5-alpha reductase . This gives it, at least in theory, a greater inhibitory action than finasteride.

In fact, it has been shown to be 3 times more powerful in inhibiting 5-alpha reductase type 2 and up to 100 times more effective on isoform 1. This translates into an ability to reduce serum DHT by up to over 90% , compared to the 60-70% obtained with finasteride.

Dutasteride and Hair: Can It Help?

We have seen how this drug is useful in the treatment of benign prostatic hyperplasia (BPH) thanks to its ability to prevent the conversion of testosterone into dihydrotestosterone (DHT) . It is known that DHT is one of the main factors responsible for the miniaturization of hair follicles in the scalp of those suffering from androgenetic alopecia .

In practice, dutasteride acts similarly to finasteride (approved for the treatment of baldness) and serenoa repens (one of the most valid natural anti-DHT supplements). However, the effectiveness of dutasteride is decidedly superior , reaching levels of DHT reduction of up to 94% , as already seen.

Most studies concern the treatment of the prostate, but some have also investigated its use in androgenetic alopecia .

For example, a study published in 2006 in the Journal of the American Academy of Dermatology in Korea confirmed the effectiveness of Avodart (trade name for dutasteride) at different doses (from 0.05 mg to 2.5 mg per day) for the treatment of androgenetic alopecia. Subsequently, in 2009 , dutasteride was approved in Korea for the treatment of androgenetic alopecia at a dose of 0.5 mg per day , the same as for the prostate.

Another study, also Korean, published in the journal Annals of Dermatology between 2009 and 2013 , involved 712 men affected by androgenetic alopecia of various degrees according to the Norwood scale . This study confirmed that dutasteride is well tolerated at a dosage of 0.5 mg daily and that the incidence of side effects is limited.

Side effect Subjects

(total 712)

Percentage. (%)
decreased libido 9 1.3 %
dyspepsia 8 1.1 %
impotence 7 1.0 %
exhaustion 5 0.7 %
altered sexual function 4 0.6 %
gynecomastia 2 0.3 %
ejaculatory disorders 1 0.1 %

Most of the (few) side effects resolved with discontinuation of the drug, and you will find all the details in the link to the study. However, this is not the section to talk about the side effects of dutasteride , which will be covered later in this article.

At first glance, it seems that there is no specific lower dose for hair, as there is with Propecia (1 mg) compared to Proscar (5 mg) for the prostate. This may leave you a little perplexed.

I must admit that finding information on the dosages used in countries where dutasteride is approved for androgenetic alopecia is not easy, probably because these countries are outside the European and American circuit. However, doing some research, I managed to find the drug Zagallo , also produced by GlaxoSmithKlein (GSK) for the Japanese market, where dutasteride is also approved for baldness.

To my surprise, I found that Zagallo is available in two strengths: the classic 0.5 mg format , but also a lower 0.1 mg version , as you can see in the image. This could indicate an attempt to offer a lower dose for those who want a less intense treatment for baldness .

In the technical sheet of Zagallo 0.1 mg androgenetic alopecia is specifically mentioned, which indicates that the logical conclusion has been reached that the dosage used for the prostate may be too high to treat baldness. This is where the reduced dosage formulation comes from , which unfortunately is not available in our country.

Anyway, I will be posting an article soon that will go into more detail about dutasteride dosage and how it compares to finasteride.

How to use

Avodart and its generic counterparts are marketed in softgel form , which are soft capsules with a gelatin shell that contains the active ingredient in liquid form.

In Italy, the official dosage for the treatment of benign prostatic hyperplasia is 0.5 mg daily , equivalent to one softgel capsule.

As for androgenetic alopecia (AGA) , since it is not approved, there is no official dosage . Those who wish to use it off-label must consult their doctor, carefully following his instructions, because as we will see, the side effects can be quite annoying.

An alternative to dosing could be to divide the capsule, as is often done with Proscar instead of Propecia (breaking it into 4 or 5 parts). However, being a soft capsule containing the active ingredient in liquid form, it is not divisible , making a direct reduction in dosage impossible.

Dutasteride: Side Effects

It is important to note that all medications can cause side effects, even those commonly used. However, this does not mean that they will occur in everyone who uses them; in fact, side effects should be considered a rare and unfortunate eventuality.

In the case of dutasteride , being a 5-alpha reductase inhibitor , the side effects are similar to those found with other drugs in this category. To avoid repeating the Avodart leaflet exactly , I will only mention the main ones:

  • Common side effects (occurs in 1 in 10 people): These include sexual effects, such as erectile dysfunction , decreased libido , difficulty ejaculating, and decreased semen volume. Another common side effect is gynecomastia , which is an enlargement of the breast gland in men.
  • Uncommon effects (occurring in 1 in 100 people): These include loss of body hair , due to changes in androgens.
  • Immune reactions : As with any drug, there are risks of allergies or hypersensitivity to the active ingredient, which could cause more or less serious allergic reactions.

A unique aspect of dutasteride is its increased ability to inhibit DHT and also act on the isoform 1 of the enzyme, which is mainly present in the brain and nervous system. This could affect brain neurosteroids , causing the so-called brain fog , a rare and controversial side effect that manifests itself with difficulty concentrating. However, there are no conclusive studies to confirm this.

As for hair , many users have reported excessive dryness and a sort of straw effect , due to reduced sebum production. This effect is linked to the inhibition of 5-AR type 1 , which is present in significant quantities in the sebaceous glands.

It should be remembered, however, that most side effects of dutasteride tend to resolve after discontinuation of the drug, although it may take some time for the symptoms to disappear completely.

Very Long Half-Life

Another crucial aspect of dutasteride is its half-life , which is about 4 weeks , which is considered extremely long. This represents the time it takes for the concentration of the drug in the body to halve. For comparison, the half-life of finasteride is about 6-8 hours.

This long half-life can be a problem in case of side effects , because, as can be seen from the graph, the elimination of the drug is very slow even after suspension. Therefore, even after a month of interruption, a significant amount of active ingredient can remain in circulation.

Below is a graph illustrating not only the greater DHT suppression compared to finasteride , but also the time it takes to clear the drug after discontinuation:

In short, to be truly “clean” from dutasteride , it can take up to 6 months !

Contraindications

It is always important to evaluate the use of the drug together with your doctor if you suffer from liver failure . Not because there are studies that attest to its danger, but for preventive reasons. Since dutasteride is metabolized in the liver, it is not indicated for people with less than optimal liver function.

Warnings and Precautions

Pregnancy

5-alpha reductase inhibitors may have harmful effects on the fetus, with the possibility of malformations of the reproductive organs. Pregnant women should absolutely avoid contact with dutasteride .

Even touching a capsule can be a risk, as the drug can be absorbed through the skin . For the same reason, children and adolescents should also avoid direct contact with dutasteride .

Another aspect to consider is the possibility of unprotected sexual intercourse , since traces of dutasteride can also be present in seminal fluid . Furthermore, those taking the drug should not donate blood until at least 6 months after stopping, to avoid the risk of transmitting the active ingredient to a pregnant partner.

PSA Monitoring

Like finasteride , dutasteride causes a 50% reduction in serum levels of PSA (prostate-specific antigen), which is used in prostate cancer screening . This can distort test results, making an accurate diagnosis more difficult.

If you need to have a PSA test , it is advisable to stop taking dutasteride at least 2 months before the test, or to inform your doctor that you are taking the drug.

Interactions with other drugs

Dutasteride is metabolized by the liver, specifically by the enzyme CYP3A4 . It is therefore essential to be careful if you are taking drugs that inhibit this enzyme, such as:

  • Ketoconazole and Itraconazole (antifungals)
  • Ritonavir and Indinavir (antivirals used for HIV/AIDS)
  • Nefadozone (antidepressant)

These drugs reduce the activity of the enzyme CYP3A4 , which can lead to a higher concentration of dutasteride in the body. As a result, the risk of side effects or unwanted effects increases.

Dutasteride: Where to Buy?

GSK’s patent expired in 2015 , and therefore, in addition to the aforementioned Avodart , the first generic or equivalent drugs based on dutasteride have begun to appear on the market , produced by major pharmaceutical companies such as Teva , Mylan , Sandoz , EG and other lesser-known ones.

In any case, it is essential to proceed with the purchase in a pharmacy , always with a medical prescription . This can be done through a red prescription for the treatment of benign prostatic hypertrophy , or with a white prescription (off-label). It is essential that the prescription is made by a doctor , since I repeat that the side effects can be significant due to the potency of the drug.

There is no denying that dutasteride is the most effective 5 -alpha reductase inhibitor available today, and its potential in treating baldness is remarkable. However, a high dosage can lead to side effects that are not always easy to manage, especially because of its long half-life . On the other hand, if you opt for a dose that is too low, the advantages over finasteride become marginal.

It is necessary to find the optimal dose together with your doctor who, if necessary, may prescribe dutasteride for the treatment of hair loss.

My personal opinion is that unless you have a poor response to finasteride and want to try the higher potency treatment of Avodart , we currently have finasteride available as an anti-DHT drug with a dosage specifically approved for baldness. Therefore, in my opinion, it is not worth the risk.

I strongly advise against doing it yourself , as this is anything but a light drug; taking it unnecessarily or making mistakes in dosages can lead to unpleasant consequences.

If you would like to share your experience with Avodart or have any questions, please feel free to leave a comment in the comment box at the bottom of the page.