Kaze your question is kinda confusing. I may be wrong but I don't think finasteride is used to reduce scalp irritation(finasteride blocks effects of DHT). I have an aculas 850a which is a 100mw 650nm laser and use it 3 times a week. I can tell you what the laser can do. It reduces inflamation and redness this I know for sure. The laser can take the red out of a pimple in a matter of 2-3 min. My scalp never itches...this could be because I use the laser or just that I don't have an itchy scalp. I think a better question for you to ask is "is Keto more effective than a laser to reduce scalp itching?" I'de say to answer your original question that the laser is more effective, however for your biggest bang for the buck- I'd use Nizoral (or any shampoo with keto) first and only if that does not take care of the itching look into getting a laser. I got my laser from ebay. It was normally almost 900.00 at the time and I got mine for 121.00 shipping included. I think they are now around 350.00.