The Sleep Wake Cycle and Vitamin B12

Recent research in which oral megadoses of methylcobalamin – the most bioactive form of vitamin B12 has been used – has shown promise as a regulator of disturbed sleep-wake rhythms and this tallies with the suggestion that B12 is a mood stabilizer.

Methylcobalamin has been particularly well-studied in Japan as a treatment for delayed sleep phase syndrome, that is, not being able to fall asleep until very late at night and needing to sleep in every morning.

Most mood disorders have a component of a disturbance of the sleep-wake cycle, so vitamin B12's apparent sleep-wake regulatory effect could help account for its mood-stabilizing benefits.

In a 1996 study by G. Mayer et al., three grams a day of methylcobalamin, but not cyanocobalamin (the form of B12 in most supplements), managed to decrease sleep time yet improve sleep quality and daytime alertness in a small group of healthy men and women.

It has been postulated that the reason why some people with normal blood levels of B12 may need megadoses of the vitamin is that they may have a B12 deficiency that is confined to the brain.

Methylcobalamin is now fairly easily available as a sublingual tablet, which is the best form in which to take it, as it is much better absorbed this way.

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