Physiologically, nail can depict the history of recent imbalances. As the American Academy of Dermatology has stated in its webpage, nail has been used as a diagnostic tool since ancient times. Nutrient deficiencies, drug
reaction or poisoning can be located through nail analysis. Nail mineral analysis reflects toxic exposure as it happened during the period of growth.
Micro Trace Minerals established reference ranges for nails in the 1980s.