Like other "natural" sugars, such as honey and agave syrup, molasses may sound like a healthier choice than refined sugar. But guess what: It's still basically just sugar (as are all those other natural-sounding options).
As far as nutrition goes, the various types of molasses differ only slightly from refined white sugar. And since molasses is eaten in such small amounts, any extra nutrients don’t add up to much.
Traditionally, molasses is the syrup left over when cane or beet sugar is made into table sugar. But molasses today is often made by blending the syrup with a sugar solution, which ensures uniform quality.
There are three kinds of molasses: light, medium, and blackstrap. Blackstrap molasses is the only form with any nutritional pluses, notably iron, calcium, and potassium. The most concentrated and caramelized type, blackstrap molasses is strong, dark, and bitter—it can hardly be called a sweetener.
See also: A Better Sugar from the Tropics?