Pyridoxine (Vitamin B6)
- What other names is Vitamin B6 known by?
- What is Vitamin B6?
- How does Vitamin B6 work?
- Are there safety concerns?
- Are there any interactions with medications?
- Dosing considerations for Vitamin B6.
Vitamin B6 is used for preventing and treating low levels of pyridoxine (pyridoxine deficiency) and the "tired blood" (anemia) that may result. It is also used for heart and blood vessel disease; high cholesterol and other fats in the blood; high blood pressure; stroke; reducing blood levels of homocysteine, a chemical that might be linked to heart disease; and helping clogged arteries stay open after a balloon procedure to unblock them (angioplasty).
Women use vitamin B6 for premenstrual syndrome (PMS) and other menstruation problems, "morning sickness" (nausea and vomiting) in early pregnancy, stopping breastmilk flow after childbirth, depression related to pregnancy, menopause, or using birth control pills, and symptoms of menopause.
Vitamin B6 is also used for Alzheimer's disease and other types of dementia or memory loss, attention deficit-hyperactivity disorder (ADHD), Down syndrome, autism, diabetes and related nerve pain, sickle cell anemia, migraine headaches, asthma, carpal tunnel syndrome, night leg cramps, muscle cramps, arthritis, preventing fractures in people with weak bones, allergies, acne and various other skin conditions, and infertility. It is also used for dizziness, motion sickness, preventing the eye disease age-related macular degeneration (AMD), seizures, convulsions due to fever, and movement disorders (tardive dyskinesia, hyperkinesis, chorea), as well as for increasing appetite and helping people remember dreams.
Some people use vitamin B6 for boosting the immune system, eye infections, bladder infections, tooth decay, and preventing polyps, cancer, and kidney stones.
Vitamin B6 is also used to overcome certain harmful side effects related to radiation treatment and treatment with medications such as mitomycin, procarbazine, cycloserine, fluorouracil, hydrazine, isoniazid, penicillamine, and vincristine.
Vitamin B6 is also used for nausea and vomiting associated with gastrointestinal illness in children and with use of birth control taken by mouth.
Vitamin B6 is frequently used in combination with other B vitamins in vitamin B complex products.
You may remember a prescription medication called Bendectin that was used for morning sickness in pregnancy. Bendectin contained vitamin B6 (pyridoxine) and a sleep-inducing antihistamine called doxylamine. The makers of Bendectin took it off the market in 1983 because they were running up expensive legal bills in defense of their product. Opponents charged it might be responsible for birth defects. Meanwhile, a product called Diclectin that is similar to Bendectin remained available in Canada, and there was research showing that neither vitamin B6 (pyridoxine) nor Bendectin seems to cause birth defects in animals. After Bendectin was removed from the market, there was no reduction in birth defects, but hospitalization rates for pregnancy-related nausea and vomiting doubled.
- Anemia (sideroblastic anemia). Taking vitamin B6 by mouth is effective for treating an inherited type of anemia called sideroblastic anemia.
- Certain seizures in infants (pyridoxine-dependent seizures). Administering vitamin B6 as pyridoxine intravenously (by IV) controls seizures in infants that are caused by pyridoxine dependence.
- Vitamin B6 deficiency. Taking vitamin B6 by mouth is effective for preventing and treating vitamin B6 deficiency.
Likely Effective for...
- High homocysteine blood levels. Taking vitamin B6 as pyridoxine by mouth alone or together with folic acid is effective for treating high homocysteine levels in the blood.
Possibly Effective for...
- Age-related vision loss (macular degeneration). Some research shows that taking vitamin B6 as pyridoxine with other vitamins including folic acid and vitamin B12 might help prevent the loss of vision caused by the eye disease called macular degeneration.
- Hardening of the arteries (atherosclerosis). As people age, their arteries tend to lose their ability to stretch and flex. Garlic and other ingredients seem to reduce this effect. Taking a specific supplement containing garlic, amino acids (part of proteins), and vitamins such as folic acid, vitamin B12, and vitamin B6 (Kyolic, Total Heart Health, Formula 108, Wakunga) seem to reduce symptoms of hardening of the arteries.
- Kidney stones. People with a hereditary disorder called type I primary hyperoxaluria have an increased risk of forming kidney stones. There is some evidence that taking vitamin B6 by mouth, alone or along with magnesium, or getting vitamin B6 injected into the vein, can decrease the risk of kidney stones in people with this condition. However, it does not appear to help people with other kinds of kidney stones.
- Upset stomach and vomiting in pregnancy. Some research suggests that taking vitamin B6, usually as pyridoxine, improves symptoms of mild to moderate nausea and vomiting during pregnancy. The American College of Obstetrics and Gynecology considers vitamin B6 as pyridoxine a first-line treatment for nausea and vomiting caused by pregnancy. Vitamin B6 (pyridoxine) plus the medication doxylamine is recommended for women who do not get better when treated with just vitamin B6 (pyridoxine). However, taking this combination is less effective than the medication ondansetron.
- Premenstrual syndrome (PMS). There is some evidence that taking vitamin B6 as pyridoxine by mouth can improve PMS symptoms including breast pain. The lowest effective dose should be used. Higher doses will increase the chance of side effects and are not likely to increase the beneficial effects.
- Movement disorders (tardive dyskinesia).Taking vitamin B6 seems to improve movement disorders in people taking certain drugs for schizophrenia.
Possibly Ineffective for...
- Memory and thinking skills in older people. One study shows that taking vitamin B6, folic acid, and vitamin B12 might help prevent certain parts of the brain from deteriorating in elderly people. However, most research shows that taking vitamin B6 along with folic acid and vitamin B12 does not improve mental function in elderly people.
- Alzheimer's disease. Early research suggests that higher intake of vitamin B6 from supplements or as part of the diet is not associated with a reduced risk of Alzheimer's disease in older people.
- Autism. Taking vitamin B6 as pyridoxine along with magnesium does not seem to improve autistic behavior in children.
- Carpal tunnel syndrome. Although some early research suggests that taking vitamin B6 as pyridoxine might relieve certain symptoms of carpal tunnel syndrome, most research suggests that this supplement does not benefit people with this condition.
- Side effects of cancer treatment. One study shows that taking vitamin B6 as pyridoxine at a high dose of 400 mg per day reduces the risk of hand-foot syndrome in chemotherapy patients by 45% compared to taking 200 mg per day. However, most research suggests that taking vitamin B6 as pyridoxine does not reduce symptoms called hand-foot syndrome.
- Colorectal polyps. Research suggests that taking a combination of folic acid, vitamin B6, and vitamin B12 does not reduce the risk of colorectal polyps in women at high risk of heart disease.
- Weak bones (osteoporosis). Research suggests taking a combination of folic acid, vitamin B6, and vitamin B12 does not prevent broken bones in people with weak bones and conditions that disrupt blood flow to the brain.
Insufficient Evidence to Rate Effectiveness for...
- Acne. Early research suggests that taking a specific product (NicAzel, Elorac Inc., Vernon Hills, IL), containing nicotinamide, azelaic acid, zinc, vitamin B6, copper, and folic acid, reduces lesion swelling and helps with the appearance of acne in adults and children.
- Preventing re-blockage of blood vessels after angioplasty. Evidence on the benefits of vitamin B6 for preventing the re-blockage of blood vessels after angioplasty is inconsistent. Some evidence suggests that taking folic acid, vitamin B12, and vitamin B6 might reduce the re-blockage of blood vessels in people treated with balloon angioplasty. But other research shows no benefit in people who underwent coronary stenting.
- Asthma. The effectiveness of vitamin B6 supplementation in children with asthma is unclear.
- Itchy and inflamed skin (atopic dermatitis (eczema)). Early research suggests that taking vitamin B6 as pyridoxine daily for 4 weeks does not reduce eczema symptoms in children.
- Attention deficit-hyperactivity disorder (ADHD). Early research suggests that taking vitamin B6 by mouth, with or without high doses of other B vitamins, might help ADHD. However, research using high doses of both vitamin B6 and vitamins seems to have no effect on ADHD symptoms.
- Cancer. Early research suggests that taking a combination of fatty acids commonly found in fish oil (EPA and DHA) along with B vitamins, such as vitamin B12, vitamin B6, and folic acid, does not reduce the risk of getting any type of cancer in people with heart disease.
- Heart disease. Analysis of data from a clinical trial suggests that taking vitamin B6, folic acid, and vitamin B12 reduces the risk of death due to blood vessel problems in people with a history of stroke or mini stroke who are not taking blood thinners. But it doesn't seem to reduce the risk of heart attack. Also, it doesn't appear to reduce the risk of death due to blood vessel problems in people already taking blood thinners.
- Side effects of birth control pills (oral contraceptives). Early research suggests that taking vitamin B6 might reduce the risk of side effects due to birth control. Vitamin B6 might reduce the risk of nausea/lack of appetite, headache, and depression in people taking birth control.
- High blood sugar during pregnancy (gestational diabetes). Early research suggests that taking vitamin B6 for two weeks improves blood sugar levels in people with gestational diabetes and low levels of vitamin B6. However, other research shows no benefit.
- Nerve pain in people with diabetes. There is conflicting evidence about the role of vitamin B6 in people with diabetes-related nerve pain (diabetic neuropathy). Some research suggests that taking vitamin B6 (pyridoxine) with thiamine or folic acid and vitamin B12 improves some symptoms of nerve pain so that people feel happier. However, the nerves do not seem to function any better.
- Painful periods (dysmenorrhea). Early research suggests that taking vitamin B6 daily might reduce painful periods.
- Behavior disorder in children caused by low serotonin levels (hyperkinetic cerebral dysfunction syndrome). Early research shows that taking high doses of vitamin B6 by mouth might have a beneficial effect on children with a behavior disorder caused by low serotonin levels.
- High blood pressure. Early research suggests that taking pyridoxine can lower blood pressure in people with high blood pressure.
- High levels of fat in the blood (hypertriglyceridemia). Early research suggests that taking vitamin B6 does not reduce high levels of blood fats called triglycerides. However, it might slightly reduce cholesterol levels.
- Nerve damage caused by tuberculosis medication. Early research suggests that taking vitamin B6 daily might reduce nerve damage caused by a drug taken for tuberculosis.
- Stopping breast milk production. Early research suggests that taking vitamin B6 daily for about one week does not stop breast milk production.
- Lung cancer. Male smokers who have higher blood levels of vitamin B6 seem to have a lower risk of lung cancer. It's not clear if taking supplements reduces the risk of lung cancer.
- Nausea and vomiting. Early research suggests that taking vitamin B6 does not reduce nausea or vomiting or improve symptoms of dehydration in children with an infection in the stomach or intestines.
- Complications in pregnancy. Taking vitamin B6 during pregnancy does not seem to reduce the risk of eclampsia, pre-eclampsia, or preterm birth. However, it may reduce the risk of tooth decay.
- Seizures caused by a high fever. Early research suggests that taking vitamin B6 daily for 12 months does not reduce the recurrence of seizures caused by a high fever in children.
- Stroke. There is conflicting evidence about the role of vitamin B6 in people with a history of stroke. Taking vitamin B6 along with other B vitamins by mouth does not seem to prevent the occurrence of another stoke in most people with a history of stroke or mini-stroke. However, it might reduce the risk of having another stroke in people with a history of stroke who are not using blood thinner medications.
- Nerve damage caused by chemotherapy. One report suggests that vitamin B6 might help reverse nerve damage caused by the chemotherapy drug vincristine. Research is needed to confirm these results.
- Boosting the immune system.
- Eye problems.
- Kidney problems.
- Lyme disease.
- Muscle cramps.
- Night leg cramps.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
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