My hair started falling out, and I found a protocol that really works to bring it back. First, hair falls out for many reasons, but stress and nutrient deficiency are the most common. This is what I did:
First, I started putting castor oil on my scalp -- just the scalp. It's thick so you can dilute it 50/50 with another oil. I used coconut oil, but olive oil will do, and it's cheaper. I put mine on at night and slept with a shower cap on to keep it off the pillow. You can just put it on for 2 hours, then wash it out. If you have mites in your scalp, this will kill those suckers. In fact, some people say this is why it helps your hair grow back.
What I use now is easier, although I still put castor oil on my edges when I need to.
I mix 1 tablespoon of diatomaceous earth in a glass of water and drink that every night on an empty stomach. DE is 85% silica, and it grows hair and nails like mad, plus it will help your skin. Be careful not to breathe it in, but it won't kill you if you do. You may cough a little. I always drink it down, then drink another glass of plain water to wash it out of my mouth.
Supplements: Biotin, CLA, Dopa Mucuna (also kills parasites), B-Complex (stress destroys B-vitamins, so this is good to take anyway) and Vit. E (don't take too much of this, EFA (essential fatty acids - I take one with fish oil, borage oil and flaxseed oil).
The DE is the bomb! My hair grew back fast, thick and darker. I had gone almost completely grey, but most of the new hair is coming in brown.
Hope this helps.
ETA: Also want to say that you need to work up to the 1 tablespoon of DE. I started at 1/2 tsp. and worked up over a number of weeks. It also kills parasites, so you may get some detox symptoms out of it.