Dear User, you need not take Multivitamin tabs for your age as you can get the required vitamins and minerals from your daily food. However if you have a vitamin deficiency or are old age, then you can take these tabs. Otherwise for a 19 yr old these tablets have no indication. Usually one tablet is taken everyday, but if you insist on taking these tablets, you can take one tablet once or twice a week, although it is not necessary. If you found my answer helpful, please leave a Positive feedback as it helps me with my Practice. Thank you.