I've got personal experience with this one. I was recommended to supplement with a combination of B6 and B12/with Folic Acid. The main reasons were to increase energy and to help with mental stress. The Folic Acid/B12 converts food into energy and assists mentally, and B6 is for mental stability/anti-stress. All I can say is I'm a believer!! Especially the B12/Folic Acid (B9). You take it sublingually (under tongue) and it acts like a digestive enzyme! Very cool! It gives you more energy and other benefits but the energy was what I noticed most. I already take a multi-vite, so I add these two in the daytime for extra energy and B6 helps with stress, etc. I FEEL better during the day when taking them. Also I believe these 3 work best as a combination. (synergy)
B12-
http://snipurl.com/q6h6 "Not only does vitamin B12 help in the formation of healthy red blood cells (which protect against anemia), it is also involved in the maintenance of the myelin sheath, the fatty substance that covers nerves and enables them to function properly. The body also needs this vitamin for cell replication, proper energy metabolism, and to create the genetic material in cells known as DNA and RNA."
B12-
http://www.healthy.net/scr/Article.asp?Id=1924 - "Vitamin B12 is the "energy" vitamin, as it often increases the energy level, whether obtained from eating the B12 foods or from supplemental use."
Folic Acid (B9)-
http://snipurl.com/q6j2 - "Folic acid is involved in every bodily function that requires cell division. It is used to generate red blood cells, help wounds heal, build muscle, and produce brain and nervous-system chemicals. It should always be taken in combination with vitamin B12, because taking only one of these B vitamins can mask a deficiency in the other."
B6-
http://snipurl.com/q6h8 "Day by day, there's probably no nutrient as actively involved in keeping your system running smoothly as Vitamin B6. Vitamin B6 partakes in no fewer than 100 chemical reactions throughout the body."
The daily amounts that worked for me (170 lbs) were:
(1) B6 - 100mg
(1-2) B12 1000mcg/Folic Acid 100mg
Took them in the daytime so no dreams!