Abstract
Nowadays, soap is one of the most widely used and accessible cleaning agents both in everyday life and industry. Its properties depend not only on the production technology but also on the raw materials used. Soap made from natural animal fats is of particular interest, as it significantly affects the physicochemical and consumer properties of the product. Horse fat products have traditionally been used in skincare and folk medicine due to their therapeutic properties. However, studies on traditional soap production remain limited. In recent years, horse fat has attracted attention as a promising component of cosmetic formulations due to its ability to restore the skin barrier and maintain skin hydration. According to scientific literature, the anti-inflammatory properties of horse fat are associated with its high content of polyunsaturated fatty acids, including linoleic acid (C18:2n6, LA) and α-linolenic acid (C18:3n3, ALA). For example, in cow fat, C18:2n6 is about 3%, and C18:3n3 is 0.5–1%, whereas in horse fat, they range from 15–25% and 3–10%, respectively. The anti-inflammatory activity of horse fat was determined by applying it to the skin of hairless mice. It was found that UV-B-induced production of IL-6 and TNF-α in the skin was significantly inhibited. The main aim of this study was to prepare soap from horse fat and investigate its properties. Two types of soap were prepared by saponification of horse fat with the addition of safflower oil (Carthamus tinctorius L.) and Trilon B. The physicochemical, microbiological, and skin irritation properties of the soaps were evaluated. All prepared soaps met the national standards. No irritation was observed in soaps containing safflower oil and Trilon B, i.e., no erythema or inflammation was detected in the application area.