The nail unit is a dynamic structure that remains mitotically active throughout life. Growth in the normal state occurs in a linear. Some nail diseases can significantly be improved when they accelerated the rate of growth such as onychomycosis (Geyer, Onumah, Uyttendaele & Scher, 2004). Topical minoxidil is one of the drugs that can increase the growth rate of the nail (Aiempanakit, Geater, Limtong & Nicoletti, 2017; Suchonwanit, Thammarucha & Leerunyakul, 2019). It may stimulate the length of the nail; however, the main mechanism, preparation, and proper concentration are still unknown. The main objective of this study is to evaluate the nail growth rates of 2% minoxidil at week 4. Twenty participants were randomly divided into 2 groups. In the first group, 2% minoxidil solutions were applied twice daily to all fingernails while the other group has applied the placebo. The nail length was measured at the baseline and 4 weeks after treatment. All fingernails were photographed and checked for side effects by a dermatologist. The result of this study shows that the mean nail growth of 2% minoxidil is longer than the placebo but could not reach statistical significance, except in the right middle finger and right little finger. The mean nail length of the right middle finger and right little finger was 3.92 ± 0.60 mm/month (P= 0.015) and 3.51±0.54 mm/month (P= 0.013), respectively.