Dutasteride VS Finasteride


Many people wonder which drug is the best for the treatment of baldness between Dutasteride and Finasteride. This article aims precisely to compare these two drugs so as to provide a reasonable answer to the question. Online it is possible to find 2 interesting studies about this question, which shows how high is the demand to clarify this doubt. For the sake of fairness, two initial premises must be made. The first is that Dutasteride to date is not a drug approved to treat androgenetic alopecia, neither in Europe nor in America. The second is that the writer has never used Avodart or equivalent. I reproduce below the two studies mentioned above.


1) The importance of dual inhibition of the 5alpha-reductase enzyme in the treatment of male hair loss: The results of a randomized, placebo-controlled comparison test between Dutasteride and Finasteride.

For those who do not know English I summarize below in Italian the salient lines of the study. I leave above instead, for those who want it, the direct link on Pubmed. This is a very special and interesting study, since it involved 416 people aged between 21 and 45 years suffering from androgenetic alopecia. It is a curious study also because drugs were not considered in the prostate area.


How was the study conducted?

The 416 men involved in the study were given the two drugs completely causally for 24 weeks (6 months), at the following dosages:

  • Placebo
  • 5 mg per day of Finasteride;
  • Dutasteride according to the following daily dosages: 0.05 mg, 0.1 mg, 0.5 mg or 2.5 mg.

If you have read our guide on Dutasteride you will know that it inhibits the 5-alpha reductase enzyme in its two different isoforms: in isoform 1, at about three times the potency of Finasteride, and in isoform 2, at an even hundred times the potency of Finasteride. In addition to this, Dutasteride manages to lower serum DHT by up to 90%, 20% more than Proscar 5mg, and can be used by taking 0.5mg daily to treat BPH (benign prostatic hypertrophy).


What was the result?

You may have noticed that, during the test, a sample of men were given Dutasteride at a dosage of 2.5 mg daily. This is a significantly high dosage, just think that it is equivalent to 5 times the dose used for the prostate. Having tested the effects of this overdose was particularly useful to better evaluate the action of the drug for the treatment of baldness, as shown by the interesting results found.

Let us now examine the most singular results by proposing some comparisons:


Comparison between Dutasteride 0.1 mg and Finasteride 5 mg

Observing the two data in question, similar results emerge with regard to the hair count, but with a much lower dosage of Dutasteride. The explanation for this phenomenon is as follows: Avodart also acts on the 5-alpha reductase most present in the scalp, i.e. type 1.

Comparison between Dutasteride 0.5 mg and Dutasteride 2.5 mg

The improvement found when comparing these two dosages is even 15% greater than in the comparison analyzed just above. The difference is due to the different inhibition of DHT at the scalp: this is 51% with the dosage of 0.5 mg and 79% with that of 2.5 mg. In the second case, the number of 5 type 1 alpha reductases that manage to be knocked down is greater because of the higher dosage. In contrast, the parameters of serum DHT suppression were similar: 92% with the 0.5 mg dosage and 96% with the 2.5 mg dosage.


What and how many side effects?

There were 11, of the total 416, subjects who decided not to complete the test because of side effects. In particular, these subjects have complained of the following disorders: decreased libido, impotence, gastrointestinal problems, neurological, muscular … It ‘s particularly curious to note, however, that 3 of these were in the placebo group! This shows that a significant role in these cases is played by the psychological aspect. However, the numbers show that both drugs have tended to be well tolerated, both in this phase 2 study and in subsequent phase 3 studies. Side effects following the 6-month trial occurred infrequently. In contrast, the 405 subjects who completed the 6-month trial experienced decreased libido as their main side effect.

In total, only 19 subjects had poor tolerance to the drug. Among all the different dosages, the most harmful was the 2.5 mg of Dutasteride, as shown by the highest incidence of side effects. Again it emerges that the psychological aspect has some weight, since as many as 2 subjects in the placebo group believed they were experiencing counter effects. However, the side effects caused by both drugs disappeared within a short time, about two months after the end of the test, except in one subject who showed more lasting problems.


2) The superiority of Dutasteride over Finasteride in regrowing hair and reversing hair miniaturization in men with androgenetic alopecia.

In 2016, a study comparing the following dosages of Dutasteride and Finasteride was published in the Indian Journal of Dermatology, Venereology and Leprology: 0.5 g of the former and 1 mg of the latter (approved for AGA). This is a significantly more recent study than the one reviewed earlier.


How was the study conducted?

The study ran for 24 weeks and included 90 men between the ages of 18 and 40. All subjects had baldness and were randomly divided into two groups. The first took 1 mg of Finasteride daily, the second 0.5 mg of Finasteride.


What was the result?

The table below shows at a glance the results of the test at the end of 6 months. The results were calculated by counting the total hair in specific 1cm square areas on the subjects’ heads at both the beginning and end of the test. To examine the ability of the two drugs to reverse the decrease in hair diameter, hair count was also done at the miniaturization stage. Between Finasteride and Dutasteride it is the latter to have caused the best results, both in reversing follicular miniaturization and in regrowing new hair.


What and how many side effects?

There were no specific side effect analyses during this test. If you look directly at the entire study report at the link above, you’ll notice that they mention are generic versus sexual-type effects equally distributed between the two different groups. As in the case of the previous study, the side effects still returned with the discontinuation of the treatment.


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