755-nm Picosecond vs. Nanosecond Alexandrite Lasers for Tattoo Removal: A Randomized, Split-Tattoo Clinical Trial

Tattoo removal has advanced with the introduction of picosecond laser technology, offering theoretical advantages over traditional nanosecond approaches. However, high-level clinical evidence comparing these modalities utilizing 755-nm alexandrite lasers is lacking.

A prospective, randomized, split-tattoo trial was performed in 30 subjects with professional (53.3%), amateur (33.3%), or cosmetic (13.3%) black/blue tattoos. Each tattoo was divided, with one half treated using a 755-nm picosecond alexandrite laser (PSAL) and the other with a nanosecond alexandrite laser (NSAL). Treatments were performed at 3-month intervals for five sessions, with 6-month follow-up. The primary outcome was clearance score on a 10-point visual analogue scale (VAS). Secondary endpoints included proportion achieving satisfactory clearance (VAS ≥7), pain, and adverse events.

PSAL achieved higher clearance scores versus NSAL (8, IQR: 6-9 vs. 5, IQR: 2.75-6.25; p < 0.0001) and greater rates of satisfactory clearance (73.3% vs. 23.3%; p = 0.0003). Complete clearance occurred in 10% of PSAL-treated sites versus none with NSAL. Pain scores were lower with PSAL (5, IQR: 3-6 vs. 5, IQR: 3-7, p = 0.023). Acute complication rates were reduced in PSAL versus NSAL: bleeding (2% vs. 8%, p = 0.031), blistering (7.33% vs. 15.33%, p = 0.044), and crusting (7.33% vs. 15.33%, p = 0.044), but hyperpigmentation occurred more frequently (21.33% vs. 12%; p = 0.043).

The 755-nm PSAL significantly outperforms NSAL for tattoo removal. Optimization of pulse parameters may further improve outcomes and minimize pigmentary sequelae.Trial Registration: Chinese Clinical Trial Registry (https://www.chictr.org.cn/) identifier: ChiCTR2300069281.