Based on the findings, it was inferred that both the KTP 532-nm picosecond laser and the alexandrite 755-nm picosecond laser may be employed to treat solar lentigines. Achievement of a successful outcome depends on proper treatment settings and endpoint observation.

• This study included 30 patients who had at least two solar lentigines on their arms; 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532-nm picosecond laser or an alexandrite 755-nm picosecond laser.

• Treatment efficacy was measured by assessing the mean luminance score (L*) at baseline and at six, and 12 weeks.

• Significant improvement in mean L* from baseline was achieved with both types of picosecond laser.

• At 12 weeks follow-up, greater improvement in mean L* was observed in lesions treated with the alexandrite 755-nm picosecond laser than treatment with the KTP 532-nm picosecond laser.

• In the alexandrite 755-nm picosecond laser and KTP 532-nm picosecond laser groups, more than 50% improvement occurred in 25 and 19 lesions, respectively.

• No difference in adverse events were observed between groups.

• The alexandrite 755-nm picosecond laser was associated with a significantly higher satisfaction score at the last visit.