Why Am I Experiencing Allergic Reactions Of Swelling, Tingling, And Difficulty Swallowing To NMN, A Substance My Body Already Produces?

Hello. Recently I began taking NMN (Nicotinamide Mono-nucleotide). The first few days that t have me a serious headache. The headache is fine now, but in its place is what seems to be the same kind of allergic reaction I get with a bee sting immediately after being stung. Swollen cheeks. Swelling around both ears. My tongue feels tingly and painful and I have a hard time swallowing. That’s as far is it goes. I never go full blown anaphylactic with Nicotinamide. My question is—how can I possibly be allergic to something my own body already produces? I’m age 53, and ai began taking this supplement to help replenish diminishing NMN levels in my body on the advice of a naturopath consult. Though I am not li get taking the NMN, I can’t help but wonder why my body is reacting this way. Do you have any thoughts on the matter which might add clarity? Cheers and all the best- Brielle.