Effects of low-level laser therapy, electroacupuncture, and radiofrequency on the pigmentation and skin tone of adult women
Journal of Physical Therapy Science
https://europepmc.org/article/MED/27313340
https://www.ncbi.nlm.nih.gov/pubmed/27313340
https://bibgraph.hpcr.jp/abst/pubmed/27313340

[Effects of low-level laser therapy, electroacupuncture, and radiofrequency on the pigmentation and skin tone of adult women]

Please refer to the paper of Janus.