Efficacy of Nd: YAG Lasers for Tattoo Removal: Systematic Review of Clinical Outcomes, Clearance Rates, and Treatment Parameters

Background Nd:YAG lasers are widely used for tattoo removal, selectively targeting deep dermal pigment with relative melanin sparing. Both nanosecond Q‐switched and picosecond‐domain systems are employed in clinical practice. Objectives To evaluate the efficacy and safety of Nd:YAG laser systems for tattoo removal, including clearance, treatment parameters, number of sessions, and adverse effects. Methods A systematic review was conducted according to PRISMA 2020 guidelines and registered with PROSPERO. MEDLINE, EMBASE, Scopus, and the Cochrane Library were searched. Eligible studies were human clinical studies (≥ 10 participants) evaluating Nd:YAG laser tattoo removal, including monotherapy and accelerated or combination protocols, reporting clearance or adverse events. Risk of bias and certainty of evidence (GRADE) were assessed. Results 46 studies were included, comprising randomized controlled trials, cohort studies, and case series. Nd:YAG lasers achieved meaningful clearance of black and blue tattoo pigments in most studies, generally requiring 4–8 sessions to reach ≥ 75% clearance. Amateur tattoos responded more favorably than professional tattoos, while colored pigments demonstrated lower and more variable clearance. Picosecond Nd:YAG systems may achieve similar clearance with fewer sessions or lower fluence. However, consistent superiority over nanosecond Q‐switched Nd:YAG was not demonstrated. Adverse events were predominantly mild and transient, mainly pigmentary alteration. Conclusions Nd:YAG lasers provide effective clearance of black and blue tattoos but require multiple sessions. Professional tattoos and colored pigments remain treatment challenges. High‐quality comparative trials with standardized outcome measures are needed to clarify the relative benefits of picosecond and nanosecond systems.