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General Information About Dutasteride

Dutasteride is a powerful inhibitor of the enzyme that converts testosterone to dihydrotestosterone (DHT), the hormone primarily responsible for hair loss in men1.

The drug is approved only for the treatment of benign prostatic hypertrophy (BPH) in the United States and Europe, but some recent studies suggest that it can also be taken for the treatment of androgenetic alopecia.

In Italy dutasteride is sold under the name of Avodart or Duagen and can be purchased in any pharmacy with a doctor’s prescription. Packages of the drug typically contain 30 0.5-gram soft capsules and last for 1 month, but a topical version is also available.


After how long does dutasteride take effect

A study published in “The Journal of Clinical Endocrinology & Metabolism” in 2004 tested on a population of about 400 people the use of dutasteride at different dosages2.

The results are very interesting: after only 4 weeks, DHT levels decreased by 50% using a dosage of 0.05 mg per day, while for a dosage of 5 mg per day the decrease reaches 100%. On the other hand, taking 0.05 mg per day of dutasteride has similar effects to the use of the drug finasteride at 5 mg per day, which is instead approved by the FDA for the treatment of androgenetic alopecia.

In addition, the post-treatment course is much longer than with finasteride: following treatment with dosages above 2.5 mg per day, after 16 weeks the DHT level is still 90% lower than pre-care levels.

In the case of the recommended concentration of 0.5 mg per day, after 4 months the level of DHT hormone is 20% lower than at the beginning.

Studies show that the drug in question is much more potent than finasteride and that the body disposes of dutasteride slowly after treatment.

If the effects of decrease of DHT are already there at one month after the beginning of the treatment, to see the effects on the skin can take up to 6 months.

Obviously, dutasteride does not allow hair regrowth in thinning areas and is a temporary solution. The final solution that allows regrowth in hairless areas still remains the hair transplant.


How does the drug work chemically

It is very common to read about the similarities between dutasteride and finasteride. In fact, both act as inhibitors of the 5α-reductase enzyme, but finasteride inhibits only its isoform 2 while dutasteride inhibits both isoforms 1 and 2.

The 5AR enzyme is important because it is the responsible of the conversion of testosterone into DHT that in high concentrations can cause BPH and also hair loss through a process of miniaturization of hair follicles. The decrease in DHT stops hair loss, and in some cases can promote hair regrowth in areas that are not completely hairless.


Dose and method of administration

The recommended daily dose of the medication is 0.5 mg, which corresponds to one capsule. The capsule should be taken in the morning, should not be chewed and should be accompanied with water.

The most important thing is to be patient and to follow the dosage recommended by the doctor. In case of forgetting a pill, one should not take an extra capsule to make up for it, and in case of taking more than one capsule per day, one should contact the doctor in charge.

A topical solution is also available on the market, which some say would allow for the same pros as the capsules but without the side effects.


Dutasteride Side Effects

The most common side effects from the use of dutasteride are:

  • Problems of ejaculation, impotence, and reduced libido
  • Vertigo, anxiety, insomnia, memory impairment
  • Allergic reactionssuch as hives or swelling on face and limbs, hirsutism

Side effects may be exacerbated by the use of dutasteride along with other medications such as verapamil (for hypertension), ritonavir (for HIV), and nefazodone (antidepressant).


Dutasteride Warning

Taking the drug is approved by the FDA and EMA exclusively for the treatment of BPH. Therefore, it is necessary to contact a doctor before starting treatment for androgenetic alopecia.

The doctor will make sure that the patient:

    • Is not a pregnantor breastfeeding woman. In fact, the active ingredient in dutasteride can cause permanent damage to the infant or fetus, and can cause pain or discharge in the breasts.
    • Do not have a leadcondition that could be more affected by treatment with Avodart or Duagen

The active ingredient in dutasteride would also be found in male seminal fluid. As a result, the use of condom is recommended in order to prevent a partner any contact with it.

The use of the drug also affects the concentration of prostate-specific antigen, or PSA, which is used to detect the presence of prostate cancer.



Dutasteride inhibits both isoforms 1 and 2 of the 5AR enzyme, which decreases levels of DHT, the hormone which is most responsible for hair follicle miniaturization and hair loss.

The drug has similar properties to finasteride, but has much stronger effects even with much lower concentrations.

The effects of decreasing DHT levels are verifiable starting from the fourth week after the beginning of the treatment, but it may be necessary to wait up to 6 months to have a visual feedback on the hair.

The administration is usually through soft capsules containing 0.5 mg of dutasteride, although there is a topical solution that could reduce the side effects of the drug.

The post-treatment phase is characterized by a slow disposal of the drug by the body according to the concentration taken: in the case of 0.5 mg per day, after 16 weeks from the end of the treatment DHT levels are still 20% lower than the pre-care levels.

The most common side effects concern problems in the sexual sphere (difficulty in ejaculation, less libido), in the psychological sphere (anxiety, depression, dizziness) and in the physical sphere (allergic reactions, hives, hirsutism).

The use of the drug is not recommended for pregnant or breastfeeding women, and should not be taken by those suffering from liver disease.

Finally, dutasteride can be interpreted as a temporary solution to androgenetic alopecia for non-glabrous areas, and does not replace the permanent solution of hair transplantation.



[1] Hannah C. Evans, Karen L. Goa, Dutasteride, 2012

[2] Richard V. Clark, David J. Hermann, Glenn R. Cunningham, Marked Suppression of Dihydrotestosterone in Men with Benign Prostatic Hyperplasia by Dutasteride, a Dual 5α-Reductase Inhibitor, 2004

[3] J. Curtis Nickel, Comparison of Clinical Trials With Finasteride and Dutasteride, 2004