Ozonized glycerin based cosmetic products lighten age spots on human facial skin

Background: why age spots form and where ozonized glycerin fits in

Age spots, also called solar lentigines, are flat patches of darker skin that become more common with age and cumulative sun exposure. They reflect an uneven build-up of melanin, the pigment produced by skin cells, and are a frequent cosmetic concern on the face and hands. Ozonized glycerin (OG) is a topical preparation made by reacting ozone with glycerin, and it has been explored as an ingredient in skincare formulations. The researchers set out to test whether OG-based cosmetic products, applied to the face, could reduce the visible pigmentation of age spots.

Study design: a split-face trial in 48 women using an instrument-based melanin measure

The trial enrolled 48 Japanese women aged 40 to 60 with facial age spots measuring roughly 2 mm to 1 cm across. It used a randomised, double-blind, split-face design: two OG concentrations - 80 ppm and 800 ppm - were each compared against a matched control formulation applied to the opposite side of the face, so every participant acted as her own comparison. The products were applied twice daily after cleansing for eight weeks. Melanin content was measured objectively with a Mexameter MX18 at baseline, four weeks and eight weeks, and adverse events were monitored throughout. The study was carried out by Mediplus Pharma, the company that developed the OG product.

Findings: melanin index fell in more participants by eight weeks, with no treatment-related adverse events

The number of participants whose melanin index decreased from baseline increased in both the 80 ppm and 800 ppm groups, and this was most evident at the eight-week measurement rather than at four weeks. No adverse events related to the OG formulations were reported over the course of the study.

What the authors concluded

The authors concluded that twice-daily application of the OG formulations was safe and effective for lightening age spots on facial skin within the eight-week period studied, at both the lower and higher concentrations tested.

Limitations of this study

This was a small, single-centre study of 48 women within a narrow age range, so the results may not extend to other groups. The follow-up was short at eight weeks, leaving longer-term durability and safety untested. The outcome was an instrument-based melanin index rather than a clinical grading of how the spots looked to an observer, and the study was funded and conducted by the product's developer, which is a potential source of bias. It is a cosmetic study of skin appearance and does not assess any medical treatment.