SAVANNAH, Ga. — The use of nano-sized ultrafine water clusters (UFW), generated by a Japanese-developed medical device and applied to the face, may reduce erythema associated with fractionated picosecond alexandrite laser (Fr-PSAL) treatment, new research suggested.

Results from a split-face, randomized pilot study of 25 women showed that the UFW-treated side of the face was correctly identified by a blinded expert in 85% of the group treated before Fr-PSAL and 92% of the group treated after the laser therapy. 

Additionally, the area of erythema was significantly reduced in the pre-laser group, and erythema density was reduced in the post-laser group. There were no adverse events. 

“Reducing a side effect in a noninvasive way is a priority,” lead investigator Kentaro Oku, MD, medical director at Hills Grace Clinic, Yokohama, Kanagawa, Japan, told Medscape Medical News.

Oku noted that although the technology was created in Japan and not yet available in the United States, he hopes that will change “in the near future.” Overall, “this is a very safe and innovative technology using a water molecule,” he said. 

The findings were presented at The American Society for Laser Medicine and Surgery (ASLMS) 2026 Annual Meeting.

Not Conventional Humidification 

UFW represents “a novel form of water with distinct physiochemical properties,” the investigators wrote in an online early report of the results. The conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT/PSS) technology absorbs atmospheric water vaper and, when heated, emits water clusters of approximately 1.4 nanometers in diameter.

“Unlike conventional humidification, UFW is nonionized and nonpolar, effectively penetrating intercellular lipids within the stratum corneum, thereby enhancing moisture retention, skin permeability, and barrier function,” the researchers reported. 

Oku added that the 1.4-nanometer diameter “is critical” to not only penetrate the skin, but to penetrate deeper. 

Fr-PSAL has shown effectiveness for such outcomes as fine wrinkles and acne scars but is also associated with post-treatment erythema. Noninvasive options for lowering the duration and intensity of erythema have been sought. 

The current study included 25 healthy women aged 25-60 years who had previously experienced erythema after Fr-PSAL for reducing pigmentation, skin rejuvenation, and/or pore tightening. The intervention consisted of UFW applied for 30 minutes before or after treatment to one side of the face, randomly chosen, with the other side acting as the control. 

The primary outcome measure was reduced erythema as assessed by a blinded evaluator (a board-certified dermatologist). An exploratory secondary outcome was hemoglobin-enhanced image analysis.

All participants were divided into either the pre-laser treatment group (n = 13) or the post-laser treatment group (n = 12). The protocol for the former group was application of UFW, followed by Fr-PSAL; images were taken immediately after the procedure and 1 and 6 hours after the procedure. The protocol for the latter group was image capture, followed by Fr-PSAL, then image capture, UFW, and a last image capture.

The Windscell device (Aisin) releases water “at a rate of 30 mcg/min by absorbing ambient humidity through the PEDOT/PSS conductive polymer layer and releasing UFW” after heating the layers, according to the report. Fr-PSAL was performed using a PicoSure Pro (Cynosure Lutronic), with a 755-nanometer wavelength and a diffractive lens array.

‘First Evidence’ 

Results showed that the UFW-treated side was correctly identified by the blinded evaluator in 11 of 12 members of the post-laser group (92%, P = .003) and in 11 of 13 members of the pre-laser group (85%, P = .01).

All participants reported having reduced stinging and heat sensations from the laser in the UFW-treated face sides.

The hemoglobin-enhanced image analysis showed a highly significant reduction in erythema density on the treated side vs the control side in the post-laser treatment group (Cohen’s d, -0.93; P = .004) and a moderately significant reduction in erythema area in the pre-treatment group (Cohen’s d, -0.57; P = .03). It also predicted which side of the face had been treated with UFW in 83% and 77% of the groups, respectively. 

“These results provide the first clinical evidence that UFW effectively reduces post-laser erythema through both therapeutic and prophylactic mechanisms,” the investigators wrote in the early report. 

However, larger confirmatory studies are now needed, Oku noted.

Potential for Broader Applications 

“I think this was a fascinating study,” session co-moderator Chris W. Robb, MD, PhD, Skin & Allergy Center, Spring Hill, Tennessee, told Medscape Medical News after the presentation.

Although this was the first time he had heard of the novel technology, Robb said he was struck by the small diameter of the water cluster. “If you can get penetration in the stratum corneum and epidermis, this could be significant,” he noted. 

The other co-moderator Jeremy A. Brauer, MD, director of Spectrum Skin and Laser, New York, agreed and applauded the results. “On a larger scale, I think this could be beneficial to our patients,” he said. 

Neither Robb nor Brauer were involved with the research. Asked whether this is a technology that could potentially be embraced if it were to become available in the United States, Robb said if that were to happen, it could have applications “across dermatology in general, especially as it portends to atopic dermatitis or even post-procedural conditions.”

Oku, Robb, and Brauer reported no relevant financial relationships.