Vitamin C Serums Linked to 14% of Skin Reactions in EADV Study of Social Media-Driven Routines

Two studies presented at the European Academy of Dermatology and Venereology (EADV) Congress 2026 in Vienna, held from 30 September to 3 October, looked at how skincare advice on social media plays out on real skin. Dermatology Times reported both.

The first, led by Ouissal Hormi, was an observational study of 94 patients who developed a new or worse skin problem after using products promoted on social media. Chemical exfoliants containing alpha- or beta-hydroxy acids were involved in 34% of cases, over-the-counter retinoids in 27%, vitamin C serums in 14% and niacinamide products in 11%. The pattern of use stood out as much as the products. Nearly half the patients, 48%, had copied an entire routine from social media, and 63% were using more than three active ingredients at the same time.

The most common problem was irritant contact dermatitis, seen in 42% of patients. Acne that started or got much worse accounted for 28%, rosacea flares or rosacea-like rashes 12%, post-inflammatory hyperpigmentation 11% and superficial chemical burns 7%. Hormi said in a statement that the striking part was not the products' popularity but the way they were being used.

The second study, led by Maria Lucia Paysano, reviewed 38 popular TikTok videos on Korean skincare found in May 2026 using a fresh account. Almost all of them, 94.7%, contained at least one potentially misleading claim. Most ignored differences between skin types, nearly half encouraged combining many actives without safety advice, only one mentioned irritation and none suggested seeing a dermatologist. No creator was a dermatologist.

The researchers stressed that their findings do not show Korean skincare itself is harmful. The reported figures come from conference presentations, not full peer-reviewed papers, and the patient study shows which products were involved rather than how often each one causes problems.

For vitamin C users, the practical point is familiar. Acidic L-ascorbic acid serums can sting or irritate, and the risk rises when they are layered with exfoliating acids and retinoids from a routine built for someone else's skin.