This study proposes a review on hyaluronic acid (HA) known as hyaluronan or hyaluronate and its derivates and their application in cosmetic formulations. HA is a glycosaminoglycan constituted from two disaccharides (N-acetylglucosamine and D-glucuronic acid), isolated initially from the vitreous humour of the eye, and subsequently discovered in different tissues or fluids (especially in the articular cartilage and the synovial fluid). It is ubiquitous in vertebrates, including humans, and it is involved in diverse biological processes, such as cell differentiation, embryological development, inflammation, wound healing, etc. HA has many qualities that recommend it over other substances used in skin regeneration, with moisturizing and anti-ageing effects. HA molecular weight influences its penetration into the skin and its biological activity. Considering that, nowadays, hyaluronic acid has a wide use and a multitude of applications (in ophthalmology, arthrology, pneumology, rhinology, aesthetic medicine, oncology, nutrition, and cosmetics), the present study describes the main aspects related to its use in cosmetology. The biological effect of HA on the skin level and its potential adverse effects are discussed. Some available cosmetic products containing HA have been identified from the brand portfolio of most known manufacturers and their composition was evaluated. Further, additional biological effects due to the other active ingredients (plant extracts, vitamins, amino acids, peptides, proteins, saccharides, probiotics, etc.) are presented, as well as a description of their possible toxic effects.

The animal kingdom, particularly reptiles, is widely recognized as a valuable source of peptides and proteins with applications in medicine, the pharmaceutical industry and, more recently, the cosmetic industry. This prompted an investigation into the prevalence of cosmetic products utilizing synthetic peptides, with a specific focus on viper venom. A major objective of our study was a comparative analysis between natural venom-derived peptides and synthetic analogues, which could provide valuable insights into the market impact. The identification and inclusion of these products were based on their listings according to the International Nomenclature of Cosmetic Ingredients (INCI), alongside a review of the current literature and the recognition of relevant studies aimed at evaluating the composition of viper venom. Additionally, cosmetics were identified through online media using specific keywords such as “viper venom”, “snake venom”, “snake”, “SYN^®-AKE”, “analogues of snake venom” or “synthetic snake venom”, followed by a comparative analysis of the products identified. The study provided an extensive background considering the market segmentation of viper venom-based and synthetic peptide-based cosmetics, including 245 cosmetics (70 manufacturers), also including the classification into Mass-Market and Premium-Market segments, which adds practical value. In 81% of the total analyzed products, the synthetic analogue was present, SYN^®-AKE (INCI Dipeptide Diaminobutyroyl Benzylamide Diacetate (and) Glycerin (and) Aqua), while 13% contained snake venom or viper venom. The high percentage of cosmetics categorized under the Mass-Market segment could be attributed to the use of synthetic peptides, given the high cost of natural viper venom as an anti-ageing ingredient, a price likely reflected in the final cosmetic product. In terms of product category, skin care cosmetics made up the largest share, followed by body care products, typically claiming anti-ageing and moisturizing properties.