Eating leafy greens, lean meat, omegas like flax and drinking lots of water has made a huge difference in my hair growth and health. I do take a multivitamin with a healthy skin support to help clear up acne and that has been improving both my hair and my skin. That multi had only 300mcg of biotin!
I think having enough protein, vitamin C, and omegas are more effective than a bazillion mcg of biotin.