You should not apply expired cosmetic products to your face, as this carries a risk of skin irritation or burns; it is also essential to avoid exposing skin to hot steam after such a reaction.

noli's read

The advice not to use expired products is based on very solid formulation principles. According to guidelines from regulatory agencies such as the ANSM or the FDA (expert opinion), preservatives in skincare products degrade over time, paving the way for the proliferation of bacteria and fungi. Furthermore, chemical stability analyses (such as those published in the International Journal of Cosmetic Science, of an observational nature) demonstrate that active ingredients and oils oxidize, potentially becoming highly irritating to the skin barrier. This chemical alteration is what causes the sensation of burning and immediate discomfort. Finally, applying hot steam to skin that is already inflamed is a counterproductive idea: heat dilates small vessels and further disrupts the epidermis's protective lipids. The creator's alert is therefore particularly accurate and scientifically validated.

the sources

No named source held this one up — that absence is part of the verdict.