The branded products (EmergenC and such) come with more of a markup But Vitamin C in general is an extremely cheap compound. The costs are going to be in thing

The branded products (EmergenC and such) come with more of a markup But Vitamin C in general is an extremely cheap compound. The costs are going to be in things like packaging, shipping, warehousing, shelf space, accounting for lost shipments and returns, and similar overhead. For simple products that overhead can be orders of magnitude more than the core product.