Scalp DHT vs Serum DHT

Dear Drs,

I was wondering which is the difference between “scalp DHT” and “serum DHT”. I guess “scalp DHT” needs “serum DHT” concentration to reach the scalp; am I right? Then, what means in the dutasteride/finasteride studies the differentiation of “scalp DHT” and “serum DHT”?

I know Avidart inhibits, 90% of serum DHT and 55% of scalp DHT, what it mean? The 55% is inhibited from the total DHT or from the 10% (respect the 90% serum inhibit)?

Thank you.

When a drug like finasteride is introduced into the body, it works its way through all of the fluid systems of your body. In theory, almost every cell in your body gets exposed to the drug and some of the cells will do something to the drug. So when you take this finasteride pill, 50% of it will remain in your blood stream after 4-6 hours, and every 4-6 hours the concentration halves.

The drug then works its way into the body fluids around the cells, and it may (finasteride does) attach to the hair follicles and the skin of the scalp. Slowly this process reverses (probably about a week), as the drug does its job on the individual hair follicles, minimizing the DHT. This DHT working, becomes less effective because of the competition for the sites in the cell. That is a very simplified way to explain how it works.

As I’ve said before, I am not a biochemist. I really do not know how scalp DHT or serum DHT are measured.