Active ingredient: dutasteride
The active ingredient dutasteride is a 5-alpha reductase inhibitor which inhibits the transformation of testosterone into dihydrotestosterone (DHT).
The medicinal product was originally developed in the USA and approved in 2002 for treatment of benign prostatic hyperplasia (BPH). However, in the course of clinical studies it was shown that the medication also has a very positive effect on hair growth among men who suffer from androgenetic hair loss.
Avodart® (0.5 mg dutasteride) is able to more strongly reduce the concentration of DHT in the scalp. Like the active ingredient finasteride (the active ingredient of Propecia®), dutasteride inhibits an enzyme named 5-alpha reductase. This enzyme transforms the male sex hormone testosterone into DHT. Yet at a more advanced age DHT has a negative effect on the growth and quality of head hair. The hairs become thinner, sparse and fall out.
Effects on the growth of hair
Two active ingredients by comparison:
- 0.5 mg dutasteride (Avodart®) per day reduces the DHT in the blood serum by 91% and in the scalp by 54%
- 0.5 mg finasteride (Propecia®) per day reduces the DHT in the blood serum by 71% and in the scalp by 38%
This means that the active ingredient dutasteride is significantly more effective. This is justified as follows: because type 1 of the 5-alpha reductase enzyme – which is inhibited by dutasteride – is only present in lesser quantities in the hair root, the effect may be less significant than assumed. The stronger effect results because it reduces the DHT in the blood serum.
The potential adverse effects are normally weakly pronounced and only of short duration. The most frequently occurring adverse effects are in connection with sexual function: impotence and diminished sexual desire (libido), etc. The reason for this is the stronger inhibition of DHT in the blood plasma.
The adverse effects of the active ingredient dutasteride were examined in another study. A total of 4,325 men age 50 and over with an enlargement of the prostate took part. The adverse effects subsided during the period of treatment.
- Impotence: 4.7% vs. 1,7% (placebo)
- Diminished sexual desire: 3% vs. 1.4%
- Ejaculation disorders: 1.4 % vs.0.5 %
- Gynaecomastia: 0.5 % vs. 0.2 %
After discontinuation of the medication, the adverse effects can still persist up to approx. six months; this is due to the long biological half-life of dutasteride.
If you are taking dutasteride, do not donate blood. Wait for approx. 6 months after completion of your treatment to avoid that a pregnant woman could possibly come into contact with the active ingredient through a blood transfusion. Avodart® can also be absorbed through the skin. That is why women who are pregnant or who are planning to have children should abstain from taking the medication, because the active ingredient can lead to anomalies in the development of male sexual organs in a male foetus. Dutasteride is not suitable for use with women or children.