When my nails stared to flake and became rather brittle, I decided to order this product because I was too scared to buy regular nail and hair supplements, which are known to have side effects or even the opposite of the desired effect. Within a week of taking biotin, flaking stopped, and now my nails are slowly getting back to normal. Nevertheless, after 3 weeks of taking the supplement, the nails are still weak and break easily. And It is not advised to take this supplement for more than a month!. So if your want to take biotin as a preventative measure - this brand would be a good choice. But if you are having some real issues with your nails or hair, I suggest investing in a more expensive and more reliable brand.