You are thinning early on, that its probably not even noticeable to anybody but you; after all, we are our own biggest critics. But perhaps a good time to start addressing it. Yes, you should go to your Doctor just to rule out anything (thyroid issue, etc etc) especially since you feel this is pretty sudden. They will probably just tell you its male pattern baldness anyways, but better to rule anything out. Is anybody on your Mothers side bald, or have thin hair?
You could use finasteride (propecia) and its effectiveness is good, but some do not tolerate it well (I am one of them). I tried using it for about a year and it made me really sick. This was back in my mid/late 20's, I would take a picture every week to compare - there was no debating that it worked. I stopped using propecia and started rogaine, back then it was just the eye-dropper to spread on your scalp, that also worked pretty good until I became sensitive/allergic to it. LOL. Now, at 42, I am on my 2nd year of a hair system and I WISH I had done it a longggggg time ago so there was no gap in my balding for years & showing up at work with a full head of hair. Not saying you are there at all, but that in this day of age, there are many options out there. Just a little advice from someone who's been there, thats all. YMMV
