Vitamin C from food boosts skin collagen

Illustration courtesy Juliet M. Pullar et al. J Invest Dermatol 2025 Oct. 29:S0022-202X(25)03509-2

A new study from the University of Otago in Christchurch, New Zealand, has found that dietary vitamin C intake directly enhances collagen production and skin renewal, offering clinical confirmation that nutrition may play a central role in skin physiology.

Published in the Journal of Investigative Dermatology, the investigation established a strong, dose-responsive relationship between plasma and skin vitamin C concentrations. The study demonstrated that consuming two vitamin C-rich SunGold kiwifruit daily for eight weeks raised skin vitamin C content, increased dermal thickness, and accelerated epidermal renewal and regeneration.

Lead author Professor Margreet Vissers of the Mātai Hāora–Centre for Redox Biology and Medicine described the results as “compelling.” “We were surprised by the tight correlation between plasma vitamin C levels and those in the skin—this was much more marked than in any other organ we have investigated,” she said in a press release. “We are the first to demonstrate that vitamin C in the blood circulation penetrates all layers of the skin and is associated with improved skin function.”

The findings address a long-standing clinical question about how best to deliver vitamin C to the skin. Although topical formulations have proliferated in cosmetic dermatology, vitamin C is water-soluble and poorly absorbed through the epidermal barrier. This new evidence, Professor Vissers said, indicates that “the skin is extremely good at absorbing vitamin C from the blood circulation,” suggesting that effective cutaneous delivery depends on optimal plasma levels achieved through diet.

Funded by Zespri International and a University of Otago Research Grant, the study had two arms. The first established baseline associations between plasma and skin concentrations in surgical tissue samples collected with support from Te Whatu Ora Canterbury and the He Taonga Tapu Tissue Bank. The second, a dietary intervention conducted in both Christchurch and Hamburg, Germany, enrolled 24 healthy adults who consumed two SunGold kiwifruit daily—equivalent to approximately 250 mg of vitamin C.

At the German site, the SGS Institute Fresenius conducted detailed biophysical analyses, including ultrasound-based assessments of dermal thickness, elasticity, and epidermal regeneration. “The other really substantial finding showed a significant increase in the participants’ skin thickness levels, reflecting collagen production and an upsurge in the regeneration of their epidermal cells,” Professor Vissers said.

The team anticipates that similar benefits may be achieved through other vitamin C-rich fruits and vegetables, including citrus, berries, capsicums, and broccoli. As Professor Vissers summarized the findings for patients: “The important thing is to keep your plasma levels optimal. We recommend five or more servings of fruits and vegetables daily, with at least one high-vitamin C food.”