Don't know about contraindications.
I have added valerian tincture for the first four flushes, used ornithine only for my last fifth flush. I found that the valerian (abt. 20 drops high quality tincture, some are no good)worked slightly better for me than the ornithine ( two 500 ml. capsules). Either way, I don't sleep too well the night after the O/G mix. Maybe one need to take more of either product???
God luck! I'll be flushing again tomorrow.