Vitamin B6 exists in three forms: pyridoxine, pyridoxal, and pyridoxamine. It plays roles in metabolism including transamination, deamination, decarboxylation, and condensation reactions. Vitamin B6 is readily absorbed in the small intestine and stored in tissues like muscles, plasma, liver, and red blood cells for around 25-33 days before being excreted mainly through urine and to a lesser extent sweat and feces. Deficiency can cause symptoms like weakness, sleeplessness, and hallucinations while toxicity from over 200mg per day may lead to peripheral neuropathy.