CLIF SHOT BLOCK ELECTROLYTE CHEWS (BLACK CHERRY)
Scoring points for portability, these simple-to-handle and easy-to-chew gels offer the most energy (200 calories) of all the varieties we compared. The 50 milligrams of caffeine comes from green tea extract and it’s flavored organically by brown rice syrup. In fact, 95% of Clif Shot’s short ingredient list is organic. (60g or 2.1 ounces

POWERBAR GEL (VANILLA)
Unlike most of its colleagues, this particular Powerbar flavor contains no added caffeine. It gives you a quick boost of quick and effective energy through its special blend of simple and complex carbs (27 grams combined). And at 15 percent of your RDI, this gel’s antioxidant vitamins C and E will be hard at work fighting free radicals while you fight your way up the Town Lake stairs. (41g or 1.4 ounces)

CARB BOOM! ENERGY GEL (APPLE CINNAMON)
This apple-pie-flavor gel wins in the lowest sodium (only 50 milligrams) and sugar (a mere 3 grams) categories. Naturally flavored with fruit juices, Carb BOOM! contains nothing artificial. The re-sealable container is also nifty: It stays fresh in your fridge for up to a year if you can’t finish it during your race. (41g or 1.4 ounces)

GU ROCTANE ULTRA ENDURANCE ENERGY GEL (BLUEBERRY POMEGRANATE)
Beyond just the typical carbs, these gels also contain an amino acid blend to help prevent future muscle soreness and inflammation. And with 35 milligrams of caffeine, GU Roctane gives you that extra push you need to complete a long run sans the unnecessary jitters. (32g or 1.1 ounces)

ACTIVE INGREDIENT: CORDYCEPS
It seems like something straight out of a scene from “Alice and Wonderland” but this parasitic fungus that grows on the heads of Tibetan caterpillars has been used by practitioners of traditional Chinese medicine for nearly 1,500 years. This strange supplement found itself in the spotlight after the 1992 Olympics when Chinese athletes attributed their wins to their cordyceps consumption.

Not surprisingly, there is limited research on the effects of the fungus. But, despite its bizarre origin, cordyceps appears to be very promising. A study published in a 2002 American Journal of Clinical Nutrition issue demonstrated that those who took the supplement increased endurance on a bicycle by almost nine percent compared to those in the placebo group. Similar results were also found in two earlier studies published in Medicine & Science in Sports & Exercise.

While still up for debate, researchers theorize that cordyceps works by helping the body use energy more efficiently through vasodilation. This blood vessel widening increases oxygenated blood flow — and nutrient delivery — to muscles and organs.

Adding to its almost mythical origin is the variety of ailments it has laid claim to treat or prevent. Nascent research in China have hinted at cordyceps’ ability to lower lipid and blood sugar levels, improve lung function, enhance sex drive and even prevent cancer.

Researchers in China are trying to understand what components of this fungus make it such a potential health tonic. In 2005, a study published in the Journal of Pharmacy and Pharmacology found a promising lead. Their results indicated that the polysaccharide, a complex structural carbohydrate of cordyceps, acts as an anti-oxidant and anti-inflammatory.

All of these potential benefits come with a price. Winning and Wood recommend ginseng before cordyceps as the fungus has similar effects but twice the cost.

Since most people are not very keen on the idea of popping caterpillar fungus pills, the majority of cordyceps supplements sold today are cultivated on grains, soybeans or in Petri dishes. It’s actually best to avoid the fungus in its original form as some fungus harvesters attach lead to the caterpillar-grown cordyceps to increase its weight and price.