Chocolate's reputation as an aphrodisiac (which it is not) goes back as far as the European conquest of Mexico.
Chocolate contains small amounts of caffeine. The cocoa bean contains between 0.1% and 0.7% caffeine, 0.2% being the most common amount found. Caffeine is also present in lesser amounts in the husk that surrounds the cocoa beans, usually from 0.5% to 0.3%.
Eating chocolate does not cause acne. Skin care experts agree that acne is not caused by any specific food.
A higher % cacao means less added sugar. For example, a 72% cacao dark chocolate has roughly 12 percent less sugar than a 60% cacao dark chocolate. Unsweetened baking chocolate is 100% cacao with no added sugar, and it is very bitter.
In general, a higher % cacao lends a more intense chocolate flavor. For example, the U.S. cacao standards require a milk chocolate to contain at least 10% chocolate liquor. Semisweet or bittersweet chocolate must contain at least 35% chocolate liquor, resulting in higher % cacao and a more intense chocolate flavor.
By law, both bittersweet and semisweet chocolates contain a minimum of 35% chocolate liquor. The difference between the two is the amount of sugar used; semisweet is indeed sweeter, and bittersweet a little more bitter.