['Seasonal variation in glycated hemoglobin levels has been observed, and sun exposure has been considered as one of the factors associated with this relationship. Fructosamine is a short-time marker of blood protein glycation.', 'We investigated the effect of seven days of sunbathing on blood fructosamine concentration in healthy volunteers using different ultraviolet radiation (UVR) protections.', 'Participants were assigned to one of three groups: group A - used a UVA and UVB absorbing sunscreen (N = 15), group B - used a UVB absorbing sunscreen (N = 18), and group C - followed uncontrolled sun protection habits (N = 22).', 'Overall, the fructosamine concentration did not change after sun exposure (baseline 248.8 μmol/l, 25-75%: 238.5 to 258.8 μmol/l vs. after 247.3 μmol/l, 25-75%: 234.9 to 261.8 μmol/l, P = 0.6637). Median change of fructosamine differed significantly between groups (A: -1.90 μmol/l, 25-75%: -17.10 to 1.80 μmol/l vs. B: -3.80 μmol/l, 25-75%: -18.50 to 2.40 μmol/l vs. C: +4.05 μmol/l, 25-75%: -3.20 to 22.0 μmol/l; one-way ANOVAP = 0.0277). After age adjustment and combining groups A and B, the difference in change of fructosamine concentration was statistically significant between groups A + B (decrease) vs. group C (increase, P = 0.0193).'] Does uVR protection influence fructosamine level after sun exposure of healthy adults?