## 1 Introduction
They can come in many forms, in the form of o/w and w/o emulsions and also stable formulations different from emulsions, emulsifier-free mixtures of ingredients with different properties and different mechanisms of action, such as body oils, lotions with oils, bath gels, or ointments. The selection of the appropriate form of the preparation depends on the skin condition, age, user preferences, and the expected therapeutic effect [14; 21]. Generally, these are hypoallergenic products that do not contain dyes, foaming agents, fragrances, or preservatives. As a result of using preparations with an embilient effect, the epidermis is regenerated, and its functioning is improved. The skin becomes moisturized, oiled, and more elastic. Moreover, it is protected against damage, cracks, peeling, and penetration of undesirable exogenous substances [22]. The ingredients of this type of preparation are embilents used in combination with humectants (e.g., urea, glycerin, sorbitol, and hyaluronic acid), but also substances with anti-pruritic, anti-aging, immunomodulatory, and bacterial biofilm-reducing properties [14]. Emollients play the role of occlusive ingredients but are also substances that replenish epidermal lipids. Raw materials with an occlusive effect include both natural and synthetic substances, e.g., esters, triglycerides, fatty alcohols, fatty acids (e.g., isopropyl myristate, isopropyl palmitate, and caprylic-capric triglyceride), ceramides, cholesterol, vegetable oils (e.g., sweet almond oil, sunflower seed oil, and forage oil), waves (e.g., beeswax, microcrystalline wax, and carnauba), animal oils (e.g., lanolin), mineral oils (e.g., paraffin oil), and silicone oils (e.g., polydimethylsiloxane). Examples of physiological epidermal lipids that regulate the proper differentiation of corneocytes are unsaturated fatty acids, cholesterol, squalenes, phospholipids, and sterols [8; 9; 14]. Over the years, the type of emollients used in cosmetics has changed. The first cosmetic emulsions used emollients of natural origin, e.g., waves, fats, and oils. Later, simple, synthetic hydrocarbons were used, including solid paraffins, paraffin oils, and petroleum jelly. Then, changing consumer expectations forced changes in the forms of emulsions so that they had better spreadability and did not give a sticky or greasy feeling, which was associated with a change in the basic chemical structure of emollients. This resulted in the introduction of numerous synthetic emollients to the cosmetic market, which ensured appropriate sensory sensations during application [8; 9; 23]. Currently, there are numerous trends in the cosmetics market related to growing ecological awareness. An example is the principle of sustainable development. It concerns the impact on environmental protection through the use of raw materials from renewable sources and the development of cleaner production methods. It is a combination of ecological and economic issues. This principle is used in the production of cosmetic raw materials as well as finished cosme [24; 25]. Another example is the popularity of the \"zero waste\" trend in the beauty world, which aims to protect all of the Earth's resources through responsible production, consumption, reuse, and recovery of all products, packaging, and materials [26; 27]. However, the strongest trend that has been observed in the cosmetics market for several years is the increased interest in raw materials and natural products. It should be noted that the term \"natural\" for many authors [28; 29; 30] of scientific publications does not necessarily always make products safer for consumers. According to Future Market Insights, the volume of the global natural products market will grow annually by about 5% until 2033 [31]. This confirms the current importance of the use of natural raw materials in cosmetic formulations, as well as those with embilient properties. [PERSON] et al. [32] undertook scientific research in this direction in their work.