A post circulating on X claims that eating two kiwifruits a day reverses signs of skin ageing, citing a study that apparently found that kiwis increased skin density by approximately 50% after eight weeks.

The post attributes this to kiwis’ high vitamin C content and suggests the fruit also improves skin cell proliferation, the process by which the skin generates new cells to replace older, damaged ones, which the post describes as key to preventing skin ageing and deterioration. The post has since garnered over 1.2 million views.

The post is one of several in a thread by X user Dalton, who runs a supplement business called Analyze & Optimize, in which he discusses the study’s findings.

What is the study?

The post references a study titled “Improved Human Skin Vitamin C Levels and Skin Function after Dietary Intake of Kiwifruit: A High-Vitamin-C Food,” published in the Journal of Investigative Dermatology in 2025 by researchers at the University of Otago in New Zealand. The study was supported by Zespri International Ltd, a kiwifruit brand widely available in Singapore.

While vitamin C has long been associated with skin health, most research had focused on topical application, such as creams and serums applied directly to the skin. The researchers noted that while studies on oral vitamin C intake and skin function existed, none had directly measured whether vitamin C consumed through food actually reached the skin, and if so, whether it made a measurable difference to skin health. This study set out to fill that gap.

The study had two parts. The first was a cross-sectional analysis of skin samples taken from 38 healthy individuals undergoing elective surgery, examining the relationship between vitamin C levels in the blood and in the skin. By comparing vitamin C levels in the blood against vitamin C levels measured directly inside the skin, the researchers observed that the two are closely linked, when blood vitamin C is higher, skin vitamin C is higher too.

The second, and the part the post refers to, was a pilot dietary intervention study involving 24 healthy adults. Participants were each given two SunGold kiwifruit (variety of kiwifruit known for its yellow flesh) daily for eight weeks, providing approximately 250mg of vitamin C per day. Skin samples were collected and analysed before and after the intervention.

 What did the study actually find?

The post claims the study found that two kiwis a day reverses signs of skin ageing. However, the study itself never uses the word “reverse.” The authors’ conclusion was more measured. They suggested that eating more vitamin C allows it to be absorbed into the skin, where it will benefit skin function.

On skin density, the study did find an approximately 48% increase in skin density among participants. However, this finding comes with a caveat that the post omits. Not all participants responded to the kiwifruit intervention. Five of the participants showed no increase in vitamin C levels after eating the kiwifruit and were excluded from the final analysis. Hence, the 48% figure does not apply to all 24 participants.

Additionally, on skin cell proliferation, the study did find an increase in cell renewal. However, like the skin density finding, this applies only to the participants whose vitamin C levels actually responded to the intervention.

On the other hand, the study found that skin elasticity of the participants slightly decreased, by approximately 7%, over the eight weeks. It also found no improvement in the skin’s ability to protect against UVA radiation, which refers to the type of ultraviolet light most associated with skin ageing, and long-term skin damage. Both findings contradict the post’s claim that kiwifruit reverses skin ageing.

 

Why kiwis?

The post attributes the skin benefits specifically to “kiwis’ sky high content of vitamin C,” implying something unique about the fruit. The study used SunGold kiwifruit because of its high vitamin C content, but the lead researcher explicitly noted that other vitamin C-rich foods, including berries, capsicums and broccoli, would likely produce similar results. The active ingredient is vitamin C, not kiwifruit specifically.

 Furthermore, the study specifically recruited participants with low baseline vitamin C levels, though what counts as “low” exists on a spectrum. Even among those recruited, not all responded to the intervention. As noted, five participants showed no measurable response, which the study attributes to their vitamin C levels already being at saturation point by the start of the intervention, meaning their bodies could not absorb more. This means the findings may only apply to those whose vitamin C levels were low enough to respond, and may not reflect results for the general population.

Taken together, the post overstates what the research shows. The study never claims to reverse skin ageing. Instead, it demonstrates that increasing dietary vitamin C in people with low vitamin C levels can improve certain measures of skin function, in a small pilot study.

Therefore, we rate the claim that two kiwis a day reverses signs of skin ageing as mostly false.

While the thread includes a link to a vitamin C supplement sold through his website, Dalton also acknowledges in response to comments that eating kiwis or other vitamin C-rich foods would achieve the same effect.

That said, overstating scientific findings to make them more attention-grabbing is a common pattern online, lending an air of credibility to supplement recommendations that the underlying research may not fully support. It is worth being mindful of this pattern when encountering health claims paired with product recommendations. In this case, the science as presented does not support the dramatic claims made.