Hi Ringer I've been taking B5 for several months now and I haven't had any adverse reactions. It's totally changed my life for the better! I only wish I had known about this miracle when I was a teenager (I'm now 40 years old) I'm pretty much pimple free and my large pores have actually shrunk making my complexion look MUCH better!! I take 18- 500 mg capsules of B5 every day. 6 in the morning 6 at noon and 6 before bed. I bought my B5 online from a place called Swanson health products. It's available at many places but they had the best price that I could find. If only people knew how well this stuff worked then all the topical treatments for Acne would go right out of business!