Introduction:Problematic skin conditions such as atopic dermatitis, acne vulgaris, and psoriasis are directly linked to microbial imbalance or 'dysbiosis'. Alterations of skin microbial communities along with other contributing factors, cause skin barrier dysfunction triggering immune and inflammatory responses. Acne is a prevalent problematic skin disorder characterized by unpleasant inflammatory lesions (e.g., pustules, papules), scars, and erythema which often cause psychological distress in acne patients. Common medications aim to reduce and control acne symptoms. However, most of these agents are associated with side effects and high cost. Therefore, alternative treatments are needed. Methods:The aim of this pilot-study was to investigate the efficacy and safety of a novel product containing probiotics and hyaluronic acid, "Infinite Skin Microbiome Serum", for the treatment of subjects with acne-prone skin or mild to moderate acne. The study involved twenty-nine healthy volunteers with such characteristics. Enrolled subjects were asked to apply "Infinite Skin Microbiome Serum" nightly for 28 days. Clinical assessments to evaluate number of papules or pustules, extension of the facial area involved by acne, erythema and skin dryness were performed by a dermatologist. Skin hydration was measured with the MoistureMeterSC. Safety and patient's satisfaction were assessed by self-perception questionnaires. Results: Topical application of "Infinite Skin MicrobiomeSerum" reduced the typical manifestations of acne while improving skin hydration after 14 and 28 days of treatment. The product was well tolerated as no side effect was reported. According to the self-perception questionnaires outcome, patients were satisfied with the treatment.Conclusions: Topical application of "Infinite Skin Microbiome Serum" for 28 days resulted in reduced acne manifestations and improved skin hydration. The product was well tolerated as no adverse effects were reported up to 30 days from the end of treatment. Study participants expressed a favorable perception of the treatment effect.