For these reasons, the tolerable upper limit of vitamin B6 is 100 mg per day for adults (3, 50 ). The amount of B6 used to manage certain health conditions rarely exceeds this amount. If you’re interested in taking more than the tolerable upper limit, consult your doctor.

The human body absorbs vitamin B6 in the jejunum. Phosphorylated forms of the vitamin are dephosphorylated, and the pool of free vitamin B6 is absorbed by passive diffusion [2].

Vitamin B6 is a water-soluble vitamin. Water-soluble vitamins dissolve in water so the body cannot store them. Leftover amounts of the vitamin leave the body through the urine.

Brain function Vitamin B6 helps to create neurotransmitters, which are important chemical messengers in the brain. It also helps regulate energy use in the brain. Some research suggests that vitamin B6 deficiency may be linked withcognitive decline and dementia.

In some people, vitamin B6 might cause nausea, vomiting, diarrhea, stomach pain, loss of appetite, headache, tingling, sleepiness, and other side effects. Vitamin B6 is POSSIBLY UNSAFE when taken by mouth in doses of 500 mg or more daily.

High levels of vitamin B6 can be toxic. And excessive levels of B6 have also been linked to insomnia. If you’re considering a B6 supplement, it’s important to work with your doctor to find the right dose.

Vitamin B6 is part of the group of essential nutrients known as the B Complex. B Complex vitamins, including B6, work to support energy metabolism in the body.* B6 helps maintain a healthy nervous system. *Along with folic acid and B12, B6 promotes heart health by supporting healthy levels of homocysteine already in a normal range.*

Safety and side effects. When used as a supplement in appropriate doses, vitamin B-6 is likely safe. High intake of vitamin B-6 through food hasn’t been shown to be harmful. However, too much vitamin B-6 also can cause: A lack of muscle control or coordination of voluntary movements (ataxia) Painful, disfiguring skin lesions.

Vitamin B-6 can also be taken as a supplement, typically as an oral capsule, tablet or liquid. People who have kidney disease or conditions that prevent the small intestine from absorbing nutrients from foods (malabsorption syndromes) are more likely to be vitamin B-6 deficient.

Drug interactions. Taking vitamin B-6 with this chemotherapy drug might reduce its effectiveness, especially when also combined with the chemotherapy drug cisplatin. Barbiturates. Taking vitamin B-6 with a drug that acts as a central nervous system depressant (barbiturate) might decrease the drug’s duration and intensity.