"Vitamin B6 is a water-soluble vitamin that exists
in three major chemical forms: pyridoxine, pyridoxal,
and pyridoxamine [1,2]. It performs a wide variety
of functions in your body and is essential for your
good health. For example, vitamin B6 is needed for
more than 100 enzymes involved in protein metabolism.
It is also essential for red blood cell metabolism.
The nervous and immune systems need vitamin B6 to
function efficiently, [3-6] and it is also needed
for the conversion of tryptophan (an amino acid) to
niacin (a vitamin) [1,7]. Hemoglobin within red blood
cells carries oxygen to tissues. Your body needs vitamin
B6 to make hemoglobin. Vitamin B6 also helps increase
the amount of oxygen carried by hemoglobin. A vitamin
B6 deficiency can result in a form of anemia  that
is similar to iron deficiency anemia... They
recommend 1.3 mg. for ages 19 to 50. 1.5 mg for women
over 50 and 1.7 mg for men over 50.
"What is the health risk of too much vitamin
Too much vitamin B6 can result in nerve damage to
the arms and legs. This neuropathy is usually related
to high intake of vitamin B6 from supplements, 
and is reversible when supplementation is stopped.
According to the Institute of Medicine, "Several
reports show sensory neuropathy at doses lower than
500 mg per day" . As previously mentioned,
the Food and Nutrition Board of the Institute of Medicine
has established an upper tolerable intake level (UL)
for vitamin B6 of 100 mg per day for all adults .
"As intake increases above the UL, the risk of
adverse effects increases ." http://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/
There are hundres of similar
reports that I could add, however most say the same
as the above report.