Forget slathering on the cocoa butter. A cup of hot cocoa might be the key to looking younger, the results of a small study suggest.

Researchers in Germany found that women who drank an antioxidant-rich brand of hot cocoa for three months developed smoother, better-hydrated skin that was less vulnerable to sunburn.

The improvements may stem from the cocoa's high levels of antioxidants called flavonols, study co-author Dr. Wilhelm Stahl, a researcher at Heinrich Heine University in Dusseldorf, said.

Flavonols are a group of plant compounds found in tea, wine and a variety of fruits and vegetables, as well as cocoa beans. Some research has suggested that these nutrients can improve blood flow and blood vessel function, and Stahl's team found evidence of increased circulation in the skin of women who drank flavonol-rich cocoa.

The study, published in the Journal of Nutrition, adds to the spate of recent research suggesting that dark chocolate may be a health food of sorts, capable of lowering blood pressure and possibly heart disease risk.

Chocolate giant Mars supported the current study and provided the high-flavonol cocoa - a product called Cocoapro that the company says is harvested and processed in a way that preserves the cocoa bean's flavonol content. A cup of the cocoa also contains more than 200 calories.

Stahl and his colleagues randomly assigned 24 women to have a daily cup of the high-flavonol cocoa or a low-flavonol cocoa. At the start and conclusion of the study, the researchers used sensitive imaging tests to measure the women's skin structure, hydration, blood flow and sensitivity to UV radiation.

After three months of hot cocoa, women in the high-flavonol group showed improvements in skin texture and thickness, as well as blood circulation and hydration, according to Stahl's team. Their skin was also less prone to burning from UV exposure.

Flavonols are not drugs, Stahl pointed out, and any subjective effects on the skin would be expected to be small - although they might accumulate over time, he noted.

There is, of course, a range of lower-calorie flavonol sources. Although Stahl said he could not speculate on whether fruits and vegetables would have comparable skin effects, he noted that there are hints from other studies that such flavonol-containing foods also benefit the skin.