I don't believe there is any evidence that biotin is effective, and it was coincidence that I first tried a supplement which contained it. I was looking for collagen, and found these close to home at Target. I tried powders, but didn't like having to mix them. The capsules I order through Amazon call for 3 per day, but I only take two. Here is the link.
Collagen Peptides for Women & Men, Type I, II, III, V, X Hydrolyzed Collagen Pills, Grass Fed Non-GMO Multi Collagen Peptides Supplements, Hair, Skin, Nail, Bones, Joint Health Support - 180 Capsules https://a.co/d/3NiSSom