Melasma is a localized, acquired hyperpigmentary skin disorder characterized by well-defined, light to dark brown patches. Based on clinical practice and extensive literature reports, tranexamic acid and reduced Glutathione (GSH) are both applied in the treatment of melasma, but their water-soluble nature presents challenges for transdermal absorption. Our preliminary basic and clinical research has demonstrated that ultrasound-assisted delivery significantly enhances the absorption of tranexamic acid and other water-soluble components. Its effect on the skin barrier is temporary and reversible.

This study aims to evaluate the efficacy and safety of a compound solution (10% tranexamic acid, 2% GSH) delivered via ultrasound for melasma treatment through a split-face controlled trial.

Inclusion Criteria:

-(1) Male or female participants aged 20 to 55 years (inclusive); (2) Subjects clinically diagnosed with melasma and confirmed by the investigator to meet the trial requirements; (3) Subjects willing to comply with follow-up observations and able to provide portrait rights for documentation purposes; (4) Understanding and willingness to participate in the clinical trial, and voluntarily signing a written informed consent form.

Exclusion Criteria:

• (1) Females who are pregnant, lactating, or planning to become pregnant during the trial period; (2) Subjects with known allergen to tranexamic acid or any excipient in the investigational product; (3) History of thrombosis or other thrombotic tendencies (e.g., hypertension, hyperlipidemia), or inability to discontinue oral contraceptives, estrogen, or prothrombin complex concentrates during the trial; (4) History of visual or ocular abnormalities (e.g. impaired vision, visual field defects, or fundus hemorrhage/edema) caused by abnormal retinal intravascular coagulation; (5) Patients with skin inflammation who have used topical steroid preparations for more than one month; (6) Presence of skin abnormalities at the trial site, such as nevi, ulcers, or erosions; (7) Any acute or chronic medical history (past or present) that may interfere with the validity or safety assessment of the trial; (8) Clinically significant abnormal laboratory test results prior to the trial; (9) Participation in any other clinical trial within 30 days prior to screening; (10) Any other condition deemed by the investigator to be unsuitable for participation in the study.