There’s been conflicting research on D-ribose, a sugar that’s part of ATP. Your muscles use ATP to fire out reps, so taking D-ribose should help make you stronger, much in the manner of creatine, which also heightens ATP function. New research shows that supplementing with D-ribose may not boost strength on your first few sets. Later, when ATP is more depleted, however, it can help you get more reps—those last few that activate the high-threshold motor units and more key growth fibers. Try taking a few grams in your pre- and postworkout drinks along with creatine.