Nutritional consultants advise differing amounts for daily supplementation, so I will not recommend a fixed amount. Best to check levels, supplement if low, and check again from time to time. This is especially true during the dark months of the season.I like the drops that can be taken under the tongue or skin creams. In this way, we bypass the stomach acid that by-mouth supplements need to survive through. Remember that these can work because Vitamin D is fat soluble and because of that, there can be a toxic dose. In other words, very high intake of a water soluble vitamin like C will be excreted in the urine if the amount is in excess of what the cells need. But, excessive levels of a fat soluble vitamin (A, D, E, K) will tend to build up in the tissues and potentially face a negative side effect.