Well, it depends on the type of vitamins and how healthy you eat. I think if you eat a well-balanced diet you shouldn't need to take vitamins. In my case I had a vitamin D deficience that was causing me some problems, mostly body pain. Once I started the vit D the aches and pains went away.

in addition to wendyrs info, we can also create other problems for our selves if we take just one vitamin or mineral to learn about this take some time to study ithyroid.com as it will tell how minerals etc need to co exist with others to gain proper balance, for example your insomnia has probably come about due to an inbalance of calcium & magnesium, calcium relaxes & we find we need twice as much when we are recieving it with magnesium although this will vary depending on an individuals requirements. also it depends on which form of a suppliment, eg, oxides aren't as well absorbed as chelates. I am constantly changing what suppliments i take by taking carefull notice of the relative symptoms that go with the deficiency or surplus. if you have no symptoms then you probably don't need to take anything other than a low dose one a day multivitamin.if i can be of any help with this you are welcome to enquire.