Comparative Efficacy of PSL vs NSL for Laser-Assisted Tattoo Removal

Young woman on laser tattoo removal procedure
A prospective study of patients seeking removal of black or colored tattoos was conducted to evaluate the relative efficacy of 2 laser-assisted tattoo removal systems.

Study data published in Journal of the European Academy of Dermatology and Venereology describe the relative efficacy and safety of 2 laser systems for tattoo removal. Comparable tattoo clearance results were obtained with laser pulses with nanosecond duration (NSL) and picosecond duration (PSL), though PSL appeared to cause less collateral skin damage.

NSL are regarded as the gold standard for removing pigmentation particles in the skin. It remains unclear whether PSL are superior for tattoo removal. To inform this gap, investigators conducted a prospective study of patients seeking removal of black or colored tattoos.

Each tattoo was split into 2 halves treated with either a new PSL or standard NSL. The picosecond laser had 2 wavelengths: 532 nm was used to treat colored tattoos and 1064 nm was used to treat black tattoos. Pulse duration was 300 or 350 ps. The nanosecond laser delivered pulses at 694 nm for 20 ns. Laser treatment was administered every 4 weeks for up to 8 total sessions. The primary outcome was tattoo clearance, appraised by patient, physician, and blinded observers on a scale from 1 (>94% clearance) to 5 (<25% clearance). Pain and adverse events were also captured by patient report.

The study cohort included 23 patients with 30 total tattoos. The majority of patients were women (74%) and mean age was 33.2 ± 9.3 years. Mean tattoo age was 13.4 ± 7.1 years. Six tattoos had been previously treated with laser; 24 had not. Most tattoos were black (80%), though 6 had colored pigment (20%). Mean number of laser treatments in the study was 5.5 ± 1.9. Per blinded observer assessment, black tattoo clearance scores were nominally better with PSL-1064 vs NSL, though the difference was not statistically significant. Similarly, no significant differences were observed between NSL and PSL-532 for the removal of colored tattoos.

Patient satisfaction scores were also comparable between treatment conditions. Pretreated tattoos responded better to laser than non-pretreated tattoos.

Patient-reported pain was much less with PSL-1064 and PSL-532 compared with NSL (both P <.001). Additionally, the duration of adverse skin events was shorter with PSL vs NSL. In particular, blistering, pruritis, and burning sensation resolved more quickly with PSL compared with NSL. Hyperpigmentation was observed with both pulse durations, though only NSL was associated with hypopigmentation. No scarring from laser treatment was detected.

PSL and NSL yielded comparable tattoo clearance rates. However, PSL may have a more acceptable side effect profile. The primary study limitation was the small cohort; further investigation in more patients is warranted.

“The present study showed that a mean number of about five treatments produced an acceptable clearance of most of the involved tattoos, in particular black tattoos,” authors wrote. “The comparison of PSL and NSL regarding the secondary endpoints reveals that the PSL caused less pain and adverse reactions and can be considered smoother and safer for tattoo removal as compared to NSL.”


Bäumler W, Breu C, Philipp B, Haslböck B, Berneburg M, Weiß KT. The efficacy and the adverse reactions of laser-assisted tattoo removal – a prospective split study using nanosecond and picosecond lasers. J Eur Acad Dermatol Venereol. Published online September 20, 2021. doi:10.1111/jdv.17674