Some symptoms of not enough vitamin D are very low energy levels, depression, and chronic pain. I thought all that was just part of aging in this crazy busy spinning world we live in. My doctor checked my D level and I was low. We are treating it with supplements now (about 2 months into it) and it has made a world of difference. I have energy I haven't had for 20 years, my lower back and sciatic pain are at about 1/3 of what they used to be. And it's easier to keep a smile on my face. Funny, I always taught my kids that happiness is a decision, not a result of circumstances.... which I still believe... but.... I have been amazed at how much easier it is to decide to be happy when your body is in balance nutritionally. It just makes sense that the Sunshine Vitamin is an important key!