Abstract
Background: One of the internal factors of premature aging is free radicals. Free radicals that are produced excessively in the skin will damage the collagen in the skin cell membranes, making the skin less elastic, and causing wrinkles or aging. Chemical compounds that can counteract free radical reactions are antioxidants. Chlorella vulgaris contains secondary metabolites such as flavonoids and phenolics which have antioxidant activity. This active component can be used as the main ingredient in safe cream preparations with natural solvents such as avocado seed oil. Avocado seeds contain lots of vitamins and fatty acids so they are safe to use as a natural solvent.

Aims and Objectives: This study aims to measure the effectiveness of C. vulgaris on the skin tested on tested animals.

Materials and Methods: The materials used in this study were stearic acid, C. vulgaris, avocado seed oil, aquadest, niacinamide, pentanol, and other cream production ingredients. The method used was direct testing on female and male rats by rubbing it once a day on the rats’ backs for 28 days. Previously, the antioxidant and toxicity values had been carried out using the 2,2-diphenyl-1-picrylhydrazyl and brine shrimp lethality test methods. Furthermore, the measurement of water content, oil content, and skin texture of the test animals was carried out. As a control cream, it was used without the addition of C. vulgaris.

Results: C. vulgaris cream has a pH of 5.5 with a viscosity of 15,200 cps. The result of smearing carried out on male and female rats was cream with the addition of C. vulgaris which had an increase in water content, higher oil, and a smoother texture than cream without the addition of C. vulgaris. The changes were more subtle in the back of the female rats with the proportion of increasing water content for 28 days of 14.6% and oil content of 6.6%.

Conclusions: C. vulgaris cream can be used as a cream that is safe to use with high antioxidant value and changes in skin texture which is better seen from the value of moisture and oil content.