More than 80 percent of Americans rely on caffeine every day for a quick pick-me-up. Unabated stress, less-than-ideal nutrition, sleep deficits, too little exercise, and not enough time spent cultivating emotional and spiritual connections all deplete our energy stores, says Woodson Merrell, MD, Director of Integrative Medicine at Beth Israel Medical Center in New York, and author of The Source: Unleash Your Energy, Power Up Your Health and Feel 10 Years Younger (Free Press, 2008). If you don’t address the source of your fatigue, your dwindling energy stores can sap your immune system (making you vulnerable to colds and other infections), drain your libido, interfere with concentration, and leave you with little energy to enjoy social events.

Caffeine certainly gives you an immediate boost—and traditional caffeinated beverages tea and coffee have other health benefits such as lowering risk of diabetes, Parkinson’s disease, and colon cancer—but they don’t address underlying fatigue factors. Herbs and supplements, on the other hand, can restock energy stores by helping maintain the balance between the body’s energy-producing and energy-consuming mechanisms, says Merrell.

If your energy levels take a nosedive (especially if this is a new development), check with your health-care provider to rule out a medical cause (such as anemia, depression, or low thyroid hormone) before trying one of these five energizing supplements.

Ashwagandha

As with other adaptogenic herbs, ashwagandha has multiple nonspecific actions in the body that boost well-being, such as improving circulation, increasing nutrient absorption by cells, and helping the body use the stress hormone cortisol more efficiently so the adrenal glands don’t need to make as much.

How to take: 300–500 mg of a standardized extract daily. It may take 3–4 weeks of use before you notice an effect. This mild herb can be taken for as long as desired.