Since March 1st 2022, Lilial is a new forbidden substance in the European Cosmetic Industry.
What is Lilial and what is it used for? Butylphenyl methylpropional (p-BMHCA) is the INCI name of the substance more commonly known as Lilial. It is an aromatic molecule, wildly used as a fragrance ingredient in many cosmetic products, including: perfumes, deodorants, antiperspirants and hair products. There is also important to consider the presence of this compound in many non-cosmetic products such as household cleaners and detergents. 
It functions as a masking agent to reduce and/or inhibit the base product odor or taste while giving it a floral scent with Lily-of-the-Valley notes.
Lilial’s classification in the EU Regulation: from restricted to banned. Until March 1st, Lilial was one of the 26 allergenic substances listed in Annex III of the EU Regulation on Cosmetic Products.  This means that the ingredient was restricted due to the fact that it was considered to be able to trigger an allergic response and induce skin sensitization. As all restricted substances, it had to be included in the list of ingredients on the label in case of exceeding a certain concentration.
In vitro studies carried out long time ago (2009) demonstrated that BMHCA gives estrogenic responses in a human breast cancer cell line in culture.  However, none in vivo experiments were performed by then, so it was not possible to determine the effects that this substance could have on living beings.
So, what has changed now? In August 2020, further investigations showed that Lilial should be classified as a CMR 1B ingredient. CMR stands for Carcinogen, Mutagenic, and Reprotoxic, while 1B is the category for the products whose effects have been proven on animals. As a result, the chemical has been banned from cosmetics and cleaning products in the EU.
Is there enough evidence to support Lilial’s toxicity? All toxicological data was extracted from animal studies, and was subsequently extrapolated to human parameters. Several routes of administration were tested, including: oral, parenteral, intraperitoneal, dermal application, within others. Most of the tests were performed on rodents, but also on other animals like pigs, whose skin’s anatomy is more similar to ours. [4 The majority were made according to guideline procedures and under Good Laboratory Practice (GLP) conditions. 
However, the data provided to the Scientific Committee on Consumer Safety (SCCS) to approve this ingredient was insufficient. Overall, the results have limited value and no firm conclusion can be drawn from those studies. Consequently, they indicated that "the potential for genotoxicity of BMHCA cannot be excluded”.
Furthermore, the SCCS expressed their concern regarding the aggregate exposure, arising from the use of different product types together, including the non-cosmetic products. The exposure scenario is higher than what expected and cannot be measured accurately. Thus, at the proposed concentrations for restricted products, Lilial cannot be considered safe.
Conclusion The Committee's decision to ban the product is a precautionary measure. They indicated that the best way to proceed was reformulating products replacing the fragrance with another one with proven safety. Even though there are no clinical studies (studies on humans) to support the currently spread-out theory that Lilial may cause infertility in humans, it is wise to be prudent and avoid it in our products for the moment.
Links of interest
If you want to delve into the association between antiperspirants and carcinogenesis, you can read our article: https://www.emotion-master-studentproject.eu/post/can-you-get-cancer-from-using-antiperspirants
If you are interested in reading the official document with the SCCS opinion: https://ec.europa.eu/health/system/files/2021-08/sccs_o_213_0.pdf
 K. Yazar, S. Johnsson , et al.,“Preservatives and fragrances in selected consumer-available cosmetics and detergents.” Contact Dermatitis. 2011 May
 Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products.
 A. Charles, P. Darbre et al, “Oestrogenic activity of benzyl salicylate, benzyl benzoate and butylphenylmethylpropional (Lilial) in MCF7 human breast cancer cells in vitro.” Journal of Applied Toxicology. 2009
 Scientific Committee on Consumer Safety (SCCS) – Opinion on the safety of Butylphenyl Methylpropional (p-BMHCA) in cosmetic products – Submission II – 2017