[mrsD]

Folate has been shown to be low in people with depression.
Same with DHA (a long chain fatty acid found in fish and fish oils).

The newest data also shows low Vit D leads to depression.

Low B12 actually damages nerves, the myelin that insulates them is maintained by B12 and other nutrients. Myelin damage also shows up as numbness/tingling and peripheral nerve pain.

Certainly B12 helps with neurological problems, but it is not the only player in nerve maintenance.

So you would have to pay attention to several things. You can be tested, for Vit D and B12. I'd get that done to see if you need them.

Many people with simple low energy complaints, do well on a simple high potency B-complex. A B-50 type or something similar once a day in the morning often makes people "feel better". That is where I would start. Many people have posted on boards that this brand was very good and useful for them:
http://www.iherb.com/B-Right-100-Capsules/110?at=0

After testing you will see if you need more B12 than this product offers.