It usually depends on the origin of the fungal infection. If it was at the “root” of the nail, improvement can be seen as early as 3 weeks. A continuous improvement will be gradual as the nail continue to grow out. Typically, a significant overall improvement will be seen after 3 months. As a rough estimate, toenails may take 9 – 12 months to grow out completely, and fingernails may take 6 – 9 months.