A sufficient amount of protein and calcium in the daily diet is important for normal growth of nails and hair. The norm of protein is 1.2 g per 1 kg of body weight, and the norm of calcium is about 1 g per day. It is important to restore growth so that protein and calcium are well absorbed. Absorption is influenced by both the quality of food and physical activity.
The most elegant remedy is a drop of retinol acetate (vitamin A). Sold in any pharmacy, cost about 60 rubles, manufacturer GalenoFarm. You will heal even the most exhausted nails in 2 weeks. The consistency is a very fatty oil, so it is better to rub it in at night.
I constantly wear gel polish and when I feel that my nails are exhausted, I take it off for a week and rub the drops into the cuticle before going to bed. A week or two, the nails become very strong. No fashionable and expensive oils, no vitamins will make nails as strong as after ordinary vitamin A.
Good luck and strong nails!