Vitamin B6, also known as pyridoxine is one of the 8 B vitamins which makes up the B complex family. It includes other compounds of the vitamin known as known as pyridoxal and pyridoxamine. Vitamin B6 is water-soluble which means your body does not store it and can be rapidly eliminated through urine.
One of the main functions of all the B vitamins is converting carbohydrates into glucose which helps the body produce energy. B-complex vitamins are needed for healthy skin, hair, eyes, and liver. Many of the B-complex vitamins also play an important role in keeping the nervous system healthy and the brain functioning properly.
Vitamin B6 is required for the production of heme and the metabolism of carbohydrates, lipids and amino acids. It is an essential nutrient to include in the diet as the body is unable to make it.
Pyridoxal 5 Phosphate (P5P) is a highly bioavailable and active co-enzyme form of vitamin B6 derived from a reaction between phosphoric acid and the primary hydroxy group of pyridoxal. 
This active form of vitamin B6 plays a very important role and is involved in the many functions of the body which includes converting food into energy, maintaining neurological functions and associated with muscle growth and repair.
Vitamin B6 has many benefits within the body, despite this there is still more that needs to be discovered about this essential vitamin as well as the other group of B vitamins. The following are some of the benefits of vitamin B6.
Improves homocysteine levels
High homocysteine levels damage blood vessels and have been linked to cardiovascular disease, thrombin generation and neurodegeneration. Studies are showing vitamin B6 in addition to vitamin B12 and B9 can help lower homocysteine levels which helps to protect blood vessels and reduce the risk of cardiovascular disease and other health conditions linked to high homocysteine levels.   
Supports eye health
Macular degeneration, one of the leading cause of vision loss is also associated with high homocysteine levels can be prevented by supplementing with various nutrients that have in an important role in eye health which includes vitamin B6.  
Improves cognitive function
High homocysteine levels has also been implicated in neuronal death which causes significant impairment of cognitive function. This can lead to a significant number of conditions such as Alzheimer’s and dementia. 
Supports healthy skin
Vitamin B6 is essential for the repair and growth of skin cells and deficiency of vitamin B6 has been an important indicator for a number of skin conditions. 
Detoxifies the liver
People with chronic liver disease have been found to have low levels of vitamin B6 which suggests that vitamin B6 supports liver function and plays an important role in filtering out chemicals and toxins from the body.  
Vitamin B6 is involved in the production of heme which is required by haemoglobin and essential for transporting oxygen in the blood by red blood cells. A deficiency of vitamin B6 has shown produce smaller and pale blood cells which may insufficiently transport oxygen and lead to the various symptoms associated with anemia. 
Relieve symptoms of rheumatoid arthritis
Vitamin B6 deficiency may exacerbate symptoms of rheumatoid arthritis which is an inflammatory disease. Vitamin B6 has shown to suppress inflammation which can significantly reduce symptoms associated with inflammatory diseases. 
Vitamin B6 deficiency has been linked to diabetes and supplements may help improve glucose intolerance and help prevent further damage. Diabetes which can be caused by birth control pills is a common health condition which can lead to further complications such as diabetic neuropathy.   
Relieves carpal tunnel syndrome
Vitamin B6 has been used in the treatment of carpal tunnel syndrome and has been used in some practices only where lab results have shown a deficiency of vitamin B6. It’s important to note that high doses used in these treatments can lead to peripheral neuropathy and other toxic effects.  
Helps with insomnia
Vitamin B6 plays an important role in aiding sleep by helping to convert tryptophan, an essential amino acid, into melatonin. Melatonin is an important hormone which helps to regulate sleep and wake cycle. Vitamin B6 deficiency has been linked to low production of serotonin which helps produce melatonin. A lack of melatonin causes insomnia.   
Vitamin B6 can cause a host of health issues related to mood disorders such as depression and mood swings as it is involved in converting tryptophan into the mood regulating hormone serotonin. 
Relieves morning sickness
Prevents hair loss
Some studies are suggesting that vitamin B6 may play a positive role in preventing hair loss. One study on women with alopecia showed that supplementing vitamin B6 for several weeks improved hair condition and reduced hair loss. 
Helps PMS symptoms
Various studies have shown some potential benefits of using vitamin B6 to alleviate symptoms of PMS. Some studies showing improvement of mood, anxiety, food cravings and back pain. This may be due to the role that vitamin B6 plays in producing neurotransmitters such as serotonin which helps to regulate mood. Vitamin B6 with magnesium supplementation has also shown to significantly improve PMS symptoms   
Vitamins: A, B1, B2, B3, B5, B9, B10, B12, C, E
Minerals: Cr, Cu, Fe, K, Mg, Mn, Na, P, Se, Zn
Minerals: Ca, Cu, Fe
Vitamin B6 can inhibit the biosynthesis of vitamin B1 (thiamine). 
Vitamin B6 works synergistically with vitamins B9 and vitamin B12 which balances homocysteine levels 
High levels of vitamin B6 might decrease zinc levels 
Vitamin B6 is found in a wide variety of foods which includes beef, pork, chicken, duck, turkey, eggs, fish, sweet potatoes, potatoes, sunflower seeds, flaxseeds, sesame seeds, dried prunes, avocados, soy beans, bananas and spinach.
Some fortified foods such as bread wholegrain cereals contain vitamin B6.
The amounts recommended for vitamins and minerals are different for each country which can be found on the government website of host country. The nutritional data for each country are based on scientific research which are presented by the scientific academies in each country to help advise governmental departments for food and human nutrition.
Below is a list of some of the countries and the EU for which nutritional guidelines are available found on corresponding official government website (including the national academy of science website for the USA).
Australia and New Zealand
Vitamin B6 supplements is available for purchase as vitamin B6 (pyridoxine) and Pyridoxal 5 Phosphate (P5P). P5P is the active bioavailable form which the body readily absorbs. Both types of this vitamin have different functions. Both forms have different side effects and it is important to be aware of these before supplementing.
The following are symptoms of a Vitamin B6 deficiency:
- Sore, Glossy Tongue (glossitis)
- Cracked, sore, red or swollen lips (cheilosis)
- Dermatitis / Skin rashes
- Scaly patches, red skin on scalp and stubborn dandruff (seborrheic dermatitis)*
- PMS symptoms worsening
- Mood Changes
- Impairsimmune function
- Low energy
- Burning, shooting and tingling pain in arms, legs, hands and feet (peripheral neuropathy)
- High homocysteine levels
- EEG abnormalities
- Impaired cognitive function
*Although seizures are quite rare the symptoms have manifested in infants and are non-responsive to anticonvulsants.
*Seborrheic dermatitis is a condition where the scalp has a dry, red, sore and flaky appearance, a worsening condtion of dandruff. However this condition can also occur around other parts that produce natural skin oil which includes the face, eyebrows, eyelids, around the nose, ears and chest.
The following can cause a vitamin B6 deficiency:
- Lack of dietary intake of vitamin B6
- Lack of dietary protein and calories
- Chronic kidney disease (CKD)
- Autoimmune disease
- Celiac disease
- Drugs that inhibit B6*
- Nutritional imbalance
A deficiency is usually corrected with vitamin B6 supplements and the underlying cause of the deficiency such as correcting malabsorption issues or eliminating alcohol intake.
Medications that can cause a vitamin B6 deficiency include: anticonvulsants, antibiotics (isoniazid, cycloserine), corticosteroids and penicillamine.
The following health conditions have been linked to a vitamin B6 deficiency:
- Liver disease / cirrhosis
- Macular degeneration
- Mood disorders (depression, mood swings)
Use of extremely high doses of more than 500 mg per day of vitamin B6 has shown to cause peripheral neuropathy which is also one of the symptoms of a deficiency in the vitamin. Toxic symptoms of vitamin B6 can be caused by high doses of vitamin B6 for a prolonged period of time.
The following are symptoms of vitamin B6 toxicity:
- Peripheral neuropathy*
- Poor muscle control
- Difficulty walking
- Frequent stumbling
- Speech problems
- Vocal changes
- Numbness and pain of extremities
- Decreased sense of pain and temperature
- Painfulskin lesions
- Sensitivity to sunlight (Photosensitivity)
Treatment involves stopping intake of vitamin B6 supplements.
*Peripheral neuropathy caused by high doses of vitamin B6 supplemental intake is more difficult to resolve than when caused by a deficiency of the vitamin.
When taking any single B vitamin regularly it is important to take a B complex to avoid an imbalance of other essential B vitamins.
It is important to check with your doctor before taking vitamin B6 supplements as it can interact with a number of drugs and reduce their effectiveness.