Can I use Dutasteride to Prevent Hair Loss Instead of Finasteride?


Hello Doctor Mohebi,

Hair Loss Treatment DutasterideI hope my letter finds you and your lovely family in excellent health.   I’m doing good as my hair is still holding on thanks to the finasteride you prescribed as well as a topical application of Toppik which is still a blessing.

I’ve been doing hormone replacement therapy for the past 4 plus months.  The therapy includes weekly injections of testosterone Cypionate, HCG injections once weekly (to prevent testicular atrophy) as well as a tablet of Arimidex three times a week to prevent aromatization (reduced estrogenic effects).

Thankfully, my strength has increased as well as my muscle mass.  I feel and look better plus I wake up “happy” every morning. Erections are no longer a problem.   However, I am finding through research that I need to switch from Finasteride to Avodart.  Avodart is better at keeping DHT at very low levels thanks to the high androgenic effects of testosterone. Finasteride is not very effective and this is particularly true at 1.25 mg/day and with a half-life of only 6-8 hours.  On the other hand, using Avodart at a low dose of .5 mgs or 2.5 mgs every other day or every three days ( on .5 mgs ) or once a week ( on 2.5mgs ), keeps DHT suppressed without affecting my strength/muscular gains from testosterone as it has a half-life of about five weeks.  A prescription of 30 pills could last me a very long time and my hair would still look great.   What are your thoughts on this?  Can you help with a prescription?


It is good to hear from you and I am glad that you wake up “happy” on a daily basis.

Here is the answer to your question:

Dutasteride is more effective than finasteride for hair loss prevention, but it has more side effects.  What you mentioned in your email was new to me.   It is important to know whether you have had any side effects with finasteride?  If yes, you are increasing the risk of side effects by going on dutasteride.

What you mentioned about the half-life of finasteride is accurate. However, the actual longevity of the effect of medication in your body is about 5 to 6 days which is due to the longer functional half-life of finasteride. In other words, the inhibiting effect of finasteride on the enzyme type II – 5 alpha reductase stays with you for over 5 days.

To summarize, switching to dutasteride increases the risk of your side effects and it does not really have a longer effect than finasteride in your body.