It is better to do tests before taking food supplements to the extent that an analysis is the means of identifying possible deficits or deficiencies. After supplementation, it also makes it possible to verify its effectiveness, ”explains Pr Vasson, pharmacist biologist. However, after a flu or a cold, general practitioners usually prescribe vitamin C or a course of multivitamins to help the body recover, without asking for analyzes first. The food supplement based on vitamins most often provides nutritional doses close to those that can normally be found in the diet. It is therefore sufficient to consume them with common sense, at certain times of the year when the body is more in demand, or in periods when the diet is less balanced.