Table 2.

Studies of zinc and hair loss

Author (year)	Demographics (hair loss group)	Measures and outcomes
Ledoux 2020 [4]	Sex: 10M/328F Age: 41.5 ± 10.2 Country: France	No difference in serum zinc levels in hair loss patients (12.3 ± 1.8 μmol/l) vs. controls (12.2 ± 1.9 μmol/l)
Katsogridaki 2018 [10]	Sex: 5M/23F Age: 38.54 ± 11.04 Country: Greece	Mean zinc levels in hair loss patients (0.46 ± 0.13 mcg/ml) vs controls (0.73 ± 0.13 mcg/ml) (p < 0.01)
Guo 2017 [9]	Sex: 1M/20F Age: 31 ± 6 Country: China	No difference in serum zinc levels in hair loss patients (88 ± 9 μmol/l) vs. controls (93 ± 13 μmol/l)
Ruiz-Tovar 2014 [5]	Sex: 0F/16F Country: Spain	Mean zinc levels in hair loss patients (72.1 ± 5.7 mg/dL) vs controls (88.7 ± 8 mg/dL) (p = 0.021)