Do not use if you are pregnant, breastfeeding, taking Levodopa, a medication used to treat Parkinson's disease, or have scleroderma, phenylketonuria, or tardive dyskinesia. Consult a healthcare practitioner prior to use if you are taking antiplatelet medication, blood thinners, antidepressant drugs such as MAOIs or SSRIs, other anti-psychotic medications, carbidopa or drugs/supplements with serotenergic activity. These may include, but are not limited to, L-tryptophan, S-adenosylmethionine (SAMe), St. John's wort, antidepressants, pain killers, over the counter cough and cold medication containing dextromethorphan, anti-nausea medication and anti-migraine medication. Consult a healthcare practitioner prior to use if you are following a low protein diet or have gallstones, a bile duct obstruction, stomach ulcers, or excess stomach acid. Consult your healthcare practitioner if symptoms persist or worsen. Discontinue use and consult a healthcare practitioner if you experience skin changes or show signs of weakness, oral ulcers, or abdominal pain accompanied by severe muscle pain. Exercise caution if operating heavy machinery, driving a motor vehicle or involved in activities requiring mental alertness. Some people may experience drowsiness, diarrhea, nausea,vomiting and abdominal pain.Folic acid supplementation may mask a B12 deficiency; ask your healthcare practitioner if you are taking sufficient B12.