Study helps explain common vitamin’s extraordinary power to reverse skin ageing

Findings could lead to clinical treatment strategies for making a person look younger than their age

Vitamin C prevents age-related thinning of the skin by switching on genes that promote skin cell growth, a new study has found.

The research, published in the Journal of Investigative Dermatology, could lead to new clinical treatment strategies using vitamin C to appear younger than one’s actual age.

“Vitamin C is a promising molecule that can be used to develop treatment for epidermal thinning, including in aging,” the study says.

The skin is the body's first line of defence against external threats, but its outermost layer, the epidermis, gradually grows thinner and loses its protective strength, contributing to ageing.

This outer layer is made of cells called keratinocytes, which originate from deeper layers and migrate upward.

Previous studies show that vitamin C plays a key role in rejuvenating skin with its antioxidant properties. Now, researchers say it helps prevent skin thinning by directly activating genes that control skin cell growth and development.

"Vitamin C seems to influence the structure and function of epidermis, especially by controlling the growth of epidermal cells,” says study author Akihito Ishigami. “We investigated whether it promotes cell proliferation and differentiation via epigenetic changes.”

Boxes of vitamin C on a pharmacy shelf in Colomiers, France (AFP via Getty)

The study assessed lab-grown cells closely mimicking human skin. Exposed to air while being nourished from underneath by a liquid nutrient medium, the cells replicated the way human skin would receive nutrients from underlying blood vessels.

When researchers applied vitamin C in concentrations comparable to those typically transported from the bloodstream into the epidermis, they found the skin showed a thicker epidermal cell layer on day seven.

In only two weeks, the inner layer was even thicker, suggesting that vitamin C was promoting the formation and division of keratinocytes.

The study also notes that the vitamin helps skin cells grow by switching on dormant genes associated with cell proliferation.

When a DNA section is bound to molecules called methyl groups, it helps suppress a gene’s activity. Vitamin C promotes the removal of such methyl groups from DNA in these skin cells, thereby helping them grow, multiply, and differentiate.

These findings finally reveal how vitamin C promotes skin renewal by triggering genetic pathways involved in growth and repair.

This could be particularly helpful for older adults or those with damaged or thinning skin, researchers say. "We found that VC helps thicken the skin by encouraging keratinocyte proliferation through DNA demethylation, making it a promising treatment for thinning skin, especially in older adults," Dr Ishigami says.