@glendap56, welcome to Mayo Connect. It's great to hear that Tagrisso is proving to be effective for you. I hope that continues for many years. I'll be interested to hear what others have to say regarding vitamins and supplements.
I take a different targeted therapy, for a different gene mutation, ALK. I don't take much other than the occasional vitamin C or multi vitamin. In the past I have noticed that taking some supplements have had a negative impact on my liver or kidney counts. Be sure to check with your oncologist and keep an eye on those numbers if you start taking more. Did you take many supplements before cancer?