US regulators have accused French cosmetics giant L’Oreal of misleading claims in marketing its Lancome line of anti-aging products.

In a letter released on Tuesday, addressed to the president of L’Oreal-owned Lancome USA, the Food and Drug Administration said some Lancome products advertised online carry claims that “are intended to affect the structure or any function of the human body, rendering them drugs” under US law.

The products under scrutiny include the Genifique Youth Activating Concentrate, which claims to boost “the activity of genes and stimulates the production of youth proteins”, according to the letter.

Another singled out is the Genifique Repair Youth Activating Night Cream, which claims to boost “the activity of genes”.

Lancome has 15 days to respond to the FDA warning with specific steps it has taken to correct the violations, according to the letter dated on Friday.

“We request that you take prompt action to correct all violations associated with your products, including the violations identified in this letter,” wrote the FDA’s Michael W Roosevelt of the Centre for Food Safety and Applied Nutrition. “Failure to do so may result in enforcement action without further notice.”

L’Oreal is the world’s largest cosmetics maker.