Advertising regulators banned a Eucerin face serum advertisement for making unsubstantiated claims that users would look five years younger. The company conducted a four-week trial with 160 people and asked them to estimate how much younger they appeared after using the product. Eucerin used those self-reported assessments to market the serum's anti-aging effects. Regulators determined the claim lacked proper scientific evidence and removed the ad from circulation. The decision reflects tightening oversight of cosmetics marketing, where companies often make age-reversal promises based on limited or subjective testing rather than rigorous clinical studies.