I would start with 900 mgs a day. With equal parts pantothenic acid and break it up over 3 times a day. People forget to take the pantothenic acid with it. It took me a long time to figure out through trial and error that they work magically together.
I believe liver problems are what caused me to be sensitive to pantethine.
If you react, then go to a tiny dose and try that. If you still react then I would not take it at all til your body stops having the clearance issues.