Overall, the study shows some small, statistically significant changes in skin elasticity, wrinkles, and resistance to UV-B radiation are caused by consumption of cocoa flavanols. It also shows that a longer, 24 week period is needed to see statistically significant differences between the treatment and placebo groups, confirming the researchers’ hypothesis that previous studies of shorter duration were not sufficient.
An important thing to note about the data is that all the treatment group measurements are reported as percentage changes compared to the placebo group - what you would really want to know as a possible consumer is how it affected your skin, not how your skin compared to someone else’s. When you dig into the group’s measurements compared to their own baseline, the numbers are slightly less impressive. Over the course of the 24 week study, the improvement in skin roughness (wrinkles) in the cocoa group was only about 1-6% from the group’s baseline measurements—a change that may not even have been visible to the casual observer. Skin elasticity fared a little bit better, showing improvements in the range of 3-9%.
The researchers did note in their analysis “... the sizes of effects were smaller than other direct curative strategies such as topical tretinoin, laser resurfacing, and chemical peeling”. They also suggested that the cocoa flavanols might be more effective in preventing wrinkles when consumed for a longer duration and starting at a younger age, rather than as a treatment once wrinkles and loss of skin elasticity have already appeared in older women.
The UV-B exposure data hold up slightly better. The median MED for the 19 participants at the start of the study was 160mJ/cm2. The placebo group’s MED was statistically unchanged compared to baseline after the 24 week study, while the 65 mJ/cm2 increase in the cocoa group’s MED was not only statistically significant, but also represented a 40% increased tolerance compared to baseline - basically a modest sun protection factor (SPF) of 1.4.
The researchers noted that the study took place in the winter, which may have had an effect on some of the measurements, particularly skin hydration. However, the length of the study does provide a benefit over previous studies that had much shorter durations (six to 12 weeks).
One other benefit of the study was that it was conducted in a homogenous population in terms of race, age, and gender. This eliminated some of the factors that may have confounded the results of previous studies. The downside, of course, is that the results can’t be readily applied outside of this specific study population, namely, middle-aged and elderly Korean women.
The length of the study is its main strength. Its main weakness is that while the data for skin roughness and skin elasticity are statistically significant, cocoa supplementation may not have produced any visible changes in wrinkles or skin appearance because the differences from baseline measurements in the treatment group were small. This lends some support to the idea that cocoa flavanols may be more useful for preventing wrinkles rather than treating existing wrinkles. The specific study population likely eliminated some noise from the data collection, but also limited its applicability more broadly.