I have had Seborrheic Dermatitis for 8 years and been to many doctors, read many forums, and finally found something that WORKS. The post I read said "I hope this helps just one person" so I'm paying it forward. I hope this helps someone. It's been 1 week and I'm 90% clear. Please try this:
MSM (methylsulphonylmethane) 8,000 mg a day (yes this is higher than recommended)
Betaine HCl 648 mg a day (make sure it includes 150 mg of Pepsin)
Biotin 10,000 micrograms a day
This combination helps your body break down proteins and metabolize zinc, potassium, and b vitamins which are needed to synthesize other molecules your body needs for a healthy scalp. I hope this works for someone else.