Where does the 4 grams of carbohydrates come from in the Optimal Electrolyte powder?

Note that there are a total of 4 grams of carbohydrates in Optimal Electrolyte. Two grams come from the D-ribose, and 2 grams come from the presence of malic acid.

The 2 grams of sugar come from the D-ribose, a natural plant sugar that helps to support energy production and occasional muscle soreness from exercise.† The D-ribose is NOT added for sweetness or flavor.

Regarding malic acid, though malic acid is not technically a major contributor of carbohydrates, the FDA calculations make this a carbohydrate. The FDA calculates carbohydrates as the following: "Total carbohydrate content shall be calculated by subtraction of the sum of the crude protein, total fat, moisture, and ash from the total weight of the food." Often in lists of nutritional information, such as the USDA National Nutrient Database, the term "carbohydrate" (or "carbohydrate by difference") is used for everything other than water, protein, fat, ash, and ethanol.^[8] This includes chemical compounds such as acetic or lactic acid, which are not normally considered carbohydrates. (malic acid would also be included here). So, while malic acid is not really a carbohydrate, its presence affects the carbohydrate calculation, and by FDA's definition/calculation, is counted as one. The 2g of additional carbohydrates listed on the label are on account of the presence of malic acid in the formulation.

†These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.