# Blyproducts as a Sustainable Source of Cosmetic Ingredients
## 4 Challenges and Considerations
### Sustainability  
The current sustainability definition comes from the \"Our common future\" report of 1987, and its core concept is that \"development must be able to meet the current needs of the population without compromising future generations to meet their own needs\" [96]. When considering byproducts and their incorporation into cosmetics or their transformation into new cosmetic ingredients, several different perspectives can be perceived. At a first glance, the use of byproducts towards any added-value solution other than regarding it as waste would be better from a resource management perspective. However, if factoring in the processing needed and logistics, it might be more sustainable to just do nothing at all. Weighing byproducts cosme against the environmental burden posed by traditional cosmetic ingredients is an interesting possibility with life cycle analysis (LCA) being a crucial tool in understanding the sustainability impact of byproduct-based cosmetics. By definition, the LCA evaluates the environmental impact of products and covers all of their life cycle from raw material extraction to raw material, and in the case of byproducts-based products, their advantage under this metric is baked in, as no raw material extraction is required; thus, the LCA will show a high degree of resource saving when compared with traditional cosmetics [97; 98]. In fact, from a practical perspective, the LCA analysis of byproducts-based green cosmetics can be divided into seven steps: (i) Design: This step can have a significant impact on the products' environmental impact, and life cycle thinking (which will consider the overall impact of a product) will create a path to increase the product's sustainability during its production [99]. (ii) Sourcing: Traditionally, this step refers to raw materials' extraction and delivery. Within a bioeconomy scenario, byproducts' use will directly affect this parameter, as their usage will allow for a significant diminution of raw materials' extraction or synthesis and create a new stream of upcycling with reduced environmental impact [100]. (iii) Manufacturing: Within this step, the critical factors considered are normally the manufacturing waste, energy consumption, and greenhouse gas emissions. This is presently being circumvented by the implementation of renewable energy sources and optimizing production procedures [101]. (iv) Packaging: This step is another one where byproducts can have a great influence on a product's sustainability claims. Presently considered the leading contributor for cosmetic sustainability efforts, packaging plays a key role in preserving the cosmetics products characteristics [102]. Presently, petrochemical plastics are used due to their multiple properties but are slowly being replaced by byproducts- or natural-compounds-based solutions capable of ensuring the cosmetics characteristics [96]. (v) Distribution: This factor impacts the raw materials, packaging, and final products' distribution. Its main contribution for the LCA analysis is the CO\({}_{2}\) emissions associated with transporting [103]. (vi) Consumer use: This phase's impact on a cosmetics LCA depends on if the product's application or storage needs energy and if water is required for its application and cleaning [104]. (vii) Post-consumer use: Last, but not least, this phase refers to the product's discharges and their impact on the environment due to the presence of biologically active substances that may interact with humans, animals, and plants. This is measured via assessment of the risk of aquatic toxicity, bioaccumulation, and biodegradation [105]. In Europe, the adoption of the LCA analysis by manufacturing companies has been emphasized and advised by the association Cosmetics Europe as a crucial tool to evaluate the impact of their products' production on a kg per kg basis [106]. Another advantage of the usage of byproducts-attained compounds in cosmetics is that most of them can be attained by \"green chemistry\" approaches.