The science behind bizarre skincare trends

In 2022, a study examined various skincare practices from 12th-Century Italy that had been cited in the writings of a famed female medieval medical practitioner called Trota of Salerno. The researchers noted that many of the suggested ingredients, such as fava beans and vinegar, are now considered to be effective for facial cleansing, exfoliating, and treating dry skin. An extract of tartar oil called tartaric acid, for instance, is now a common ingredient in modern skincare.

Geisha facials and menstrual masking 

It’s not just plants, herbs and minerals found in nature. The so-called “Geisha Facial” involves taking excrement from nightingale birds, sanitising it using powerful ultraviolet light, mixing it with other chemicals such as an exfoliant and a brightener, before applying it like a face mask. This coprocentric technique originates from a centuries-old Japanese discovery that the droppings of Japanese bush warblers, a type of nightingale, could be used as a dye remover in fabrics. This then led to the droppings being used by Japanese female entertainers for skin whitening and removing their heavy makeup.  

Nowadays, it’s popular in various clinics around the world as a way of brightening the skin, and again, there could be some sound science behind it. According to Zeichner, nightingales leave particularly high concentrations of urea in their droppings, a chemical with such potent skin softening qualities that it’s commonly incorporated into moisturisers. 

It also contains high concentrations of the amino acid guanine. “Amino acids have been shown to have hydrating and brightening benefits,” says Zeichner. “But it’s important to say that these [treatments] use purified, modified nightingale droppings. You shouldn’t just scoop up bird poop off the street and rub that onto your face.”