Have you ever wondered that a cosmetic product that might last for days or months can have a higher life expectancy than a human being? No? If not, you should ask yourself “but how is it possible?”. The answer to the question, although quite simple, normally goes unnoticed by most consumers, that somehow forget the impact of the plastic packaging behind the beauty industry.
The challenge to reduce a plastic footprint of 500 billion dollars per year  due to the increased environmental awareness represents a significative and positive change worldwide. The consumer is not solely centered in the product function, but in all the benefits associated to it, including if it can somehow bring, besides individual, a collective and global well-being without losing its capacity of supplying innovation [2,3].
For the cosmetic industry, however, it could also mean a possible drawback in the development of new cosmetic products . An innovative formula is not enough anymore, only when allied with an environmentally friendly characteristic: the key is to rethink product design. Nevertheless, it can be very difficult sometimes to find good alternatives for plastic packaging that are cheap and reliable for consumers .
In this sense, a backward step was made and solid cosmetics, which were initially commercialized before World War I and II, have re-arisen as a great opportunity to connect quality of formulation with global market’s needs .
Formulating usually liquid products such as shampoos, conditioners, and moisturizers, which are mainly composed by water, into solid cosmetics represent a constraint for formulators . Still, the advantages outweigh the disadvantages: solid cosmetics have an extended shelf-life, a lower amount of preservatives used, and reduced costs of transportation, when compared to liquid ones . Moreover, surfactants that were considered harmful for the environment, like Sodium Dodecyl Sulfate (SDS) can be replaced in solid formulations by natural products, especially clays in the case of shampoos .
Another challenge for solid cosmetics formulation is to mimic the sensoriality and efficacy of conventional liquid products, once that bringing satisfaction is a main objective in this journey . Using again shampoos as an example, the foam formation is essential, because it is associated with cleansing effect, which is the main claim for this kind of item, and this is one more time related to formulation and costs challenges .
Naturally, solid cosmetics are not a perfect alternative and have associated risks. The main risk can be considered in terms of toxicity evaluation of these products. For example, a shampoo is applied to the scalp and its ingredients penetrate the blood circulation, what means that none of them can be toxic, and this highlights the importance of the safety appraisal of this type of cosmetic, demanding much more efforts from the regulatory point of view .
Overall, the transformation of cosmetic products into greener and ecofriendly formulations is eminent and extremely needed. Nonetheless, it is not an easy task to accomplish and, so far, there is no magic trick to achieve it, except by focusing huge R&D efforts on finding alternatives (e.g., solid cosmetics or biodegradable packaging) and doing exhaustive research on the topic, as a way to meet consumer expectations.
 “The beauty industry generates a lot of plastic waste. Can it change?”. Available at: https://www.nationalgeographic.com/environment/article/beauty-personal-care-industry-plastic. Accessed on 23 of July 2021.
 “Introduction to solid cosmetics”. Cosmeticsobs, Congress Reports, 2021. Available at: https://cosmeticobs.com/en/articles/congress-reports-48/introduction-to-solid-cosmetics-5742 . Accessed on 23 of July 2021.
 “The boom of solid cosmetics”. Cosmeticobs, Congress reports, 2021. https://cosmeticobs.com/en/articles/cosmetics-trends-25/the-boom-of-solid-cosmetics-4263 . Accessed on 23 July 2021.
 GUBITOSA, J.; RIZZI, V.; FINI, P.; COSMA, P.. “Hair Care Cosmetics: From Traditional Shampoo to Solid Clay and Herbal Shampoo, A Review”. Cosmetics, v. 6, n. 1, p. 13, 2019. https://doi.org/10.3390/cosmetics6010013