Everyone wants to have thick, strong nails that look nice. Who hasn't wondered what vitamins or supplements to add to their diet in order to have stronger, thicker nails that grow faster?
There are a lot of misconceptions out there and little accurate information on this topic available on the internet. I'll go over the most commonly mentioned foods and supplements and let you know why only a few of them are worthwhile in regards to nail growth.
AKA Vitamin B7, Biotin is a water soluble vitamin that is heavily involved in energy metabolism. Biotin has been studied in the treatment of something called Brittle Nail syndrome (1, 2, 3). Basically, these are people whose nails split very easily. With 2.5 mg a day (2500 mcg) nails increase in thickness by 25% with less splitting. One study commented that subjects had increased rates of nail and hair growth, though this is pretty hard to quantify and they did not measure it.
If you're looking for a vitamin known for improving hair and nail growth, Biotin is definitely the best choice. While you can find tablets easily, you should know that some people experience increased pimples with Biotin use. I'm not certain why this is (I haven't found anything about biotin and acne in literature searches or any of my derm textbooks), but it is frequently mentioned on-line in forums like Makeup Alley. Many report the problem improves with changing brands, so I wonder if this is related to a filler in the particular brand chosen.
Prenatal vitamins typically contain what is in your multivitamin and then some. Do they improve your nails? They might. If you aren't eating a balanced diet a prenatal vitamin (or a regular multivitamin) will help your skin, hair and nails. Prenatal vitamins typically contain more Biotin than regular vitamins, though not as much as I suggested above. If you're taking prenatals while pregnant, the pregnancy itself is more responsible for changes in hair, nails and skin than the vitamin.
I think this is the one I heard the most often while growing up. Yes, gelatin is a protein. Unfortunately your body breaks it down and the components go to the entire body, not only to the nails. So, this has no affect on the nails.
Likely this stems from the whole "milk is good for your bones".... therefore it must be good for your nails? The structure of a fingernail is very different from that of a bone. True, there is calcium in there. But, it's a very small amount just kind of...hanging out. So, calcium itself won't help much, though milk as part of a balanced diet is always good for your skin, hair and nails.
I've found numerous references in on-line articles stating that Omega-3s are good for your hair, skin and nails, though nothing more specific regarding the nails. In the skin, Omega-3s are an important component of the cellular membrane and help with maintaining the skin barrier as well as decreasing inflammation and irritation in various skin conditions. I assume the role in nail health is related to maintaining moisture levels within the nail, since Omega-3s do help with this in the skin.
Just keep in mind that in order to actually get the Omega-3s if you are eating fish, you'll need to spring for the wild caught not the farm raised fish. The Omega-3s are from something the wild caught fish eat, and whatever that is it is not available at the fish farm.