 [ Symptoms ] vitamin d level was 15 my doctor prescribed 50 000 iu every other day details are below so my vitamin d level was 15 last year i did nothing about it unfortunately but i was  always sleepy   i would take long naps during the day  i can not concentrate   anxious  knee pain once in a while it starts hurting and feeling really stiff goes away with rest i feel bad because i am in college and i do not have time for this i have lots of work to do do you guys think this is because of my vitamin d levels also what other tests should i do to determine the cause thanks a lot [ Disease ] i do not know what you mean by you do not have time for this  curing a vitamin d deficiency is as easy as taking a pill once a day low vitamin d levels have been associated with bone pain general muscle weakness and even cancer thought that is unlikely in a young person it is doubtful your sleepiness and lack of concentration are due to vitamin d deficiency but i suppose anything is possible you do not need any other test to determine the cause of your low vitamin d levels it is pretty simple you are not consuming enough vitamin d and you are not getting enough sunlight on your skin this is a very common problem on the one hand we medical professionals tell people to wear sunscreen on the other hand we tell them they are deficient in vitamin d the solution is to continue wearing sunscreen when you go in the sun for prolonged periods of time and to take vitamin d supplements if you have no personal or family history of skin cancer you probably are safe to get 15 30 minutes of sun per day on your skin this will help boost your vitamin d levels given how very deficient you are in vitamin d i hope you took the prescribed 50 000 iu of vitamin d every other day until the prescription was gone the usual length of therapy is a couple of weeks you should get re tested if you have not already done so and then you may need to continue taking inexpensive vitamin d supplements for awhile until your levels are within normal range please note you should not continue taking 50 000 iu of vitamin d indefinitely that is a very large dose if you have any questions consult your health care provider wishing you well i do not believe the answer is always so cut and dry my vitmain d level has been low and getting lower for at least 5 years now i do not tolerate the heat or sunshine so i do not get very much sun but i have been pushing myself to tolerate it but i have been on several very high courses of good quality vitamin d supplements and the mainstays of my diet are all vitamin d rich but there was never even a slight rise in my levels at last check my levels were in the single digits incidentally i am always tired and always in pain these days absolutely i have had similar symptoms along with cardiac and autoimmune disorders my vitamin d level is 13 and has runned low for years i too never worried about vitamin d but i have found out that it is a huge problem and runs in my family related to synthesis problems of vitamins and enzymes have levels check regularly even after normal labs and please take your vitamin d with lots of sunshine and diet rich in vitamin d c