Salmon DNA, Bird Droppings and Vampire Facials: What the Science Says About Viral Skincare

At the You & I Clinic in Seoul, one of the most requested skin texture treatments involves injecting tiny fragments of salmon sperm DNA into the dermis, the thick middle layer of skin that holds blood vessels, nerves and glands. Kyu-Ho Yi, an aesthetic physician at the clinic and an adjunct professor at Yonsei University, says the aim is not volume, as with a filler, but what he calls skin priming or biostimulation: supporting a healthier dermal environment and recovery.

Yi says the idea comes from regenerative medicine and wound healing, where fish DNA fragments drew attention for their potential to stimulate tissue repair in people with facial scars from combat injuries. The data remain relatively sparse, but some studies suggest the treatments, which use purified polynucleotides from the sperm, may reduce the appearance of fine lines. Joshua Zeichner, an associate professor of dermatology at Mount Sinai Hospital in the US who has also consulted for skincare companies, says they have been shown to help hydration, plumpness, texture and wrinkles. He adds that it is unclear how anyone first decided to try this on skin, but it is in use regardless.

South Korea is now seen as a trendsetter in aesthetics, the so-called K-Beauty craze, and the appeal of salmon and other fish sperm injections has spread worldwide, encouraged by celebrities from Charli XCX to Jennifer Aniston. Alongside them have risen other odd-sounding treatments, including facemasks made of bird droppings and blood-drawing vampire facials.

Strange skincare is not new. Cleopatra is rumoured to have bathed in sour donkey milk. Women in Myanmar have worn thanaka, a paste of ground tree bark, for centuries, both as decoration and as sun protection. One notorious Roman blemish remedy called for the ground-up guts of a small crocodile. Some of the old ingredients have survived scrutiny: turmeric, tiger grass and seaweed appear in modern products for their anti-inflammatory and hydrating effects. A 2022 study examined 12th-century Italian skincare practices cited by the medical practitioner Trota of Salerno and found that ingredients such as fava beans and vinegar are now considered effective for cleansing, exfoliating and treating dry skin. Tartaric acid, extracted from tartar oil, is a common modern ingredient.

The so-called Geisha Facial uses droppings from nightingales. They are sanitised with powerful ultraviolet light, mixed with chemicals such as an exfoliant and a brightener, and applied like a mask. The technique traces to a centuries-old Japanese discovery that droppings from Japanese bush warblers, a type of nightingale, could remove dye from fabric, which led Japanese female entertainers to use them for skin whitening and removing heavy makeup. Zeichner says the droppings are especially high in urea, a skin-softening chemical common in moisturisers, and in the amino acid guanine, and amino acids have shown hydrating and brightening benefits. But the treatments use purified, modified droppings, he stresses: you shouldn't scoop bird poop off the street and rub it on your face. He also notes that many studies of these treatments were funded by the beauty industry or run by scientists employed by those companies.

Researchers are far less enthusiastic about menstrual masking, a TikTok trend of period blood face masks. A 2018 study suggested plasma from menstrual fluid might enhance wound healing more than regular blood plasma, but Beibei Du-Harpur, a dermatology researcher at King's College London, is unconvinced. No clinician would recommend it, she says, calling it a trend born of shock factor and the hunt for views.

She is more optimistic about platelet-rich plasma injections, the vampire facial. A patient's own blood is spun in a centrifuge to concentrate growth factors, the proteins that tell cells to grow, divide and repair, and then injected into facial skin with microneedles. Interest in the approach spans osteoarthritis, joint problems, alopecia and wound healing. For skin the evidence is mixed, though some studies found improved elasticity in people in their 50s and 60s, and fewer wrinkles and less pigmentation. Du-Harpur says results vary, because centrifuge machines differ and because people naturally carry different concentrations and types of growth factors.

Looking ahead, scientists point to better collagen supplementation. One recent industry-funded study used supplements with amino acids engineered for collagen replacement and reported better skin texture, hydration and elasticity over six months, plus an average 1.4-year reduction in biological age by saliva DNA tests. Other work targets the skin microbiome with prebiotics and postbiotics. Last year South Korean researchers described a bacterium found in blood that makes postbiotics able to reduce inflammation, oxidative stress and collagen damage, though only in petri dishes.

Zeichner's test for any newcomer is whether it beats the products already on the market, which he calls an open question. Rather than a $500 (£375) facial for a one-off glow, he would have people keep to sunscreen in the morning and, at night, a moisturiser with a collagen-stimulating ingredient such as retinol.