Hi, I ve gone through your query and I understand quite well your concern Biotin, is one of the B-complex vitamins that is essential for the body’s energy and metabolism.Biotin is a natural substance in foods and available as a supplement. It is a key vitamin for encouraging the production of protein for nail growth.Biotin helps fuel the body by converting food into glucose. In addition, biotin helps the body metabolize fats and proteins for healthy skin and hair, and maintains energy to support the nervous system. Biotin encourages nail growth and is absorbed in the core of the nail, the part embedded in the finger where cells are generated. Biotin supplements might help promote thicker nail growth and has marked success with two-thirds of his patients. Biotin supplements are used to prevent and treat biotin deficiency. The dosage for healthy nails: a starting dose of about 700mcg of biotin per day and sometimes as high as 1000mcg to stronger nails with less splitting. Although there are some disagrees,it is shown that people who take biotin more than 60% has shown improvement after six months. Biotin in general is safe, but very sensitive people can experience biotin overdose symptoms such as: skin eruptions, itchiness in the skin, rashes etc. Biotin does not effect or interact with the Warfarin. I want also to remember that; 1.despite using supplements, it s very important to have an healthy diet, because supplements do not substitute food nutrients!!! 2. Please start a healthy diet because you can find biotin in many of the foods that you eat, such as carrots, eggs, tomatoes, almonds, cauliflower, cucumber, goat’s milk, cow’s milk, raspberries, strawberries etc Hope this information is helpful to you Dr. Ermira Biu