Hi People can have reactions to quite a lot. It is more likely the more foreign the compound is and how complex it is. A dye that binds to normal proteins makes those proteins very weird and they are very large and complex. So poison ivy and some chemical irritants are the most reactive compounds. Normal nutrients like Carnitine are much less likely but there can be dyes or other compounds in the Carnitine or if it came from or was contaminated with shellfish or nuts this could be an issue. BUT tea s or other compounds of herbs are more common for allergies/hives. Take Care Regards Dr. Matt Wachsman, Addiction Medicine Specialist