@johnbishop —The vitamin company contacted me. I answered all their questions regarding my medical history. As I expected, no answers were provided. They suggested I contact my physician. I told them I want to eliminate a supplement until I find the one causing the bitter taste. I talked to them about my suspicions of B6 and B12. They told me those vitamins would not be responsible for the bitter taste because they are water soluble. I know those are water soluble but thought it could cause a bitter taste while in my body. Anyways, I will keep researching. I can’t believe today there is no answer.