Is there such a thing and do they really work or are they just another gimmick?

Vitamin C, Iron and Zinc supplements can all help to grow hair, eyebrows, eyelashes and even nails quickly and healthily. Just make sure you get them from The VitaminShoppe or something of that nature and not off of Dr. Oz. If it's organic and doesn't have some fun fruity name then you'll have the right stuff, but if you see something that looks fishy then it probably is just some gimic or even if it says it contains vitamins or the zinc/iron it has other additives that are unnecessary. The other thing to keep in mind is price, if it's more than $10 for a small bottle it's definitely not what you're looking for, typically you can pick up a bottle of supplements at the drugstore for $2-6.