###### Abstract  
This review provides a comprehensive Life Cycle Assessment (LCA) of a cosmetic cream to assess the environmental impacts throughout its entire life cycle, from raw material extraction to disposal, using the methodology according to international standards. The LCA was performed using the OpenLCA 2.0.1 software, with data from the Ecoinvent 3.8 database and relevant literature. The assessment focused on multiple impact categories, including climate change, acidification, eutrophication (freshwater, marine and terrestrial), ecotoxicity (freshwater), human toxicity (cancer and non-cancer), ionizing radiation, land use, ozone depletion, photochemical ozone formation, resource use (fossils, minerals and metals), and water use. The LCA of a cosmetic cream containing gold nanoparticles revealed significant environmental impacts across critical categories. The total climate change potential was 2596.95 kg CO\({}_{2}\) eq., driven primarily by nanoparticle synthesis (60.7%) and electricity use (31.9%). Eutrophication of freshwater had the highest normalized result (3.000), with nanoparticle synthesis contributing heavily, indicating the need for improved wastewater treatment. The resource use (minerals and metals) scored 1.856, while the freshwater ecotoxicity reached 80,317.23 CTUe, both driven by the nanoparticle production. The human toxicity potentials were \(1.39\times 10^{-6}\) CTUh (cancer) and \(7.45\times 10^{-5}\) CTUh (non-cancer), linked to emissions from synthesis and energy use. The LCA of the cosmetic cream revealed several critical areas of environmental impact. The most significant impacts are associated with gold nanoparticle synthesis and electricity use. Addressing these impacts through optimized synthesis processes, improved energy efficiency, and alternative materials can enhance the product's sustainability profile significantly. life cycle assessment; cosmetic cream; environmental impacts; gold nanoparticles +
Footnote †: journal: Applied sciences  
0000-0001-5870-387X][PERSON]  
1 Faculty of Mechanical Engineering, University of Maribor, 2000 Maribor, Slovenia; [EMAIL_ADDRESS] 2  
Zlotama Celje d.  
In the cosme industry, pursuing innovative ingredients has become central to meeting consumer preferences for high-performance and sustainable products. Gold nanoparticles (AuNPs), for instance, have gained popularity due to their reported skin benefits, including anti-ageing and hydrating properties. However, despite their functional advantages, there are growing concerns about the environmental and toxicological implications of AuNPs, related mainly to their synthesis, size-dependent toxicity and potential environmental release [3; 4]. Adapting their shapes, sizes and surface characteristics makes AuNPs usable in other fields, in printable inks for electronics, for catalysis, colorimetric sensors, microscopy probes and in several biotechnology applications, used in diagnostics, therapy, or as drug carriers [5; 6]. They also exhibit significantly different effects and toxicological risks with their various size, shape and surface configurations, within a size range from 1 nm to several 100 nm, as spheres, rods, stars, etc., with surfaces capped with citrate, polyethylene glycol, and so on. Some indicate no toxicity or toxic effects, while others induce inflammatory responses, toxic effects or cell death. These responses are highly dependent on their characteristics, as well as the tissues and cell types where they are present [5]. In cosmetic creams, their effects on the skin, accumulation through the skin and their safe use are the main point of the investigations. Studies indicate that smaller AuNPs (below 20 nm) exhibit greater skin penetration and may pose higher toxicological risks. In comparison, larger particles (40 nm and above), tend to show lower toxicity levels [7]. The interaction between AuNPs and other ingredients in cosmetic formulations complicates the overall understanding of their safety, necessitating more detailed assessments.