I lost a lot of hair from prednisone and methotrexate use. Mthx is a cancer drug drug for autoimmune diseases. This went on for over 25 years, so my hair was thin, to say the least.
On an RA forum, someone said take zinc and Biotin. I was already taking zinc, so Biotin was added. It took a year, but I gained back hair I had not seen since the early 1990's. I was delighted! So you might want to try that.
If your alopecia is auto-immune, perhaps you should see a doctor? There may be drugs to help.
As far as Scripture, if it is auto-immune, well that is a disease. There is no where in the Bible it says to not treat a disease. But even if it from other causes, it is still something that is not right with your body. (I'm assuming this isn't some kind of early on-set male pattern baldness?). My grandfather was almost completely bald. The Spanish flu after WWI, which killed a lot of his friends, and affected half of the world, caused his hair to fall out, even though he was in his early 20's.
Do you have a diagnosis? Or are you just assuming because there is hair on your brush and in the sink/shower, you have alopecia? Because, everyone loses about 100 hairs a day. It's when you are losing 1000, like I was, that you start to worry. Or do something about it!
And remember, God is in control, he loves you, and he doesn't want you to be upset! But, despite the warnings not to be vain about our appearances, this is not a salvic issue. So, even if it was in the Bible that you shouldn't use men's hair stimulants, you wouldn't lose your salvation over it. But, you might feel uncomfortable and out of fellowship with God. Then, you would want to do something about it.