Yeah but you gotta remember "vitamins" is just a dumbed down term to refer to fats and compounds. It's not actually like food or anything nourishing for the hair. Like a lot of haircare stuff has vitamin e in it, which is supposed to help protect hair from hot blow drying damage and also make it shiny. A lot of the stuff is also moisturizers for your scalp.
Vitamin and mineral supplements. You only need supplementation if you have a specific deficiency, and deficiencies are not extremely common. Most people who take supplements do not need them and are just peeing out all the extra vitamins they're putting in their bodies.
If you think you have a deficiency, explain why to a doctor. A blood test to know for sure is simple. A doctor will know what kind of supplementation would best serve you, and there may be an underlying reason that can be treated to fix it. Also eat some god damn vegetables you fat little piggy