Hi. Thanks for your query. Noted the history taking so many supplements like fish oil, Gingko biloba, glucosamine, B12, D3 and Vitamin C and you got constipated. Out of these Vitamin D was started recently about 1 week ago. If you were taking other supplements before taking Vitamin D and were not constipated, the obvious reason is Vitamin D. But also look for the foods and beverages that you have take, whether they too can cause constipation. Keep yourself well hydrated. Take a mild laxative and see without any laxatives and Vitamin D also needs to be stopped and see the results. If Vitamin D has caused this you may please stop the oral form and take injection Vitamin D to avoid constipation. Get the Vitamin D levels in the blood checked and see if you really need it or not.