Brittle Nails redux

Oops, I forgot--one more aging issue. I asked my new dermatologist what she recommends for soft, splitting nails. Her advice combines internal and external treatments. The external part: put almond oil on nails with a Qtip, then buff the nails. Guess the buffing enables the oil to adhere to the nails. She said do this once a week and don't use nail polish again until the nails have healed. The internal: in addition to Omega 3 fish oil, which I already take, she recommended taking something called biotin--3 mg per day. I found a vitamin product called Hair, Skin and Nails, which has biotin plus some other stuff. So I bought that and just started taking it. My nails do look better--except for one that has a big diagonal split in it. But then I've been staying out of the garden due to the high temperatures and my propensity to overdo it once I get going...