I went to my private m.d. thinking i possibly had low testerone levels( low ibido, lack of energy, mood swings). Blood work was done, then redone and shows testerone level ok, in the lower end of ok but the doctor said my vitamin D levels were very low. She perscribed me vitamin D 50,000iu one a day for 1 week then 1 a month for 3 months.She stated she was confident i would feel alot better in just a week. my question is why? are they two closely related, vitamin d and testerone? thank you in advance.