Google translated you question to "To who the supplements of synthetic vitamins are useful?" and I think it's safe to assume it's close to what you asked.

Actually most people don't need vitamin supplements. If your diet is balanced and diversified, you don't have digestion problems and you're exposed to the sun for at least 5 minutes a day, most likely you don't need them. If not (e.g. you're vegetarian, don't eat well, drink a lot of alcohol, over 50 years old, pregnant, and some other situations) you should be tested for vitamin deficiency and consult your doctor.