Coconut water is the latest fad in sports hydration. Advertisements boldly proclaim the beverage’s benefits: More hydrating than regular water! Filled with nutrients! Cholesterol and sugar-free!

Some companies go a step further and make this unusual claim: They say coconut water is identical to human plasma and can be injected directly into the human bloodstream. Is this true?

The story has its origins in World War II, when British and Japanese soldiers were given coconut water intravenously because saline solution was in short supply. But under normal circumstances, doctors today say while it might not be harmful, they wouldn’t be inclined to set up a coconut water IV for dehydrated patients.

Coconut water is the water found inside a young coconut. It shouldn’t be confused with coconut milk, which is made from grated coconut meat. Coconut water is usually sterile and when mixed with plasma can act very much like saline. However, doctors say its sodium content isn’t high enough to stay in the bloodstream for very long. And an infusion of coconut water could cause the levels of another electrolyte, potassium, to become too high.

However, doctors do agree that coconut water is a good drink for hydration. Those electrolytes we just mentioned? They’re salts that play a major role in the biochemistry and physiological processes of the human body. In severe cases of dehydration, the electrolyte balance is thrown out of whack and can create serious problems.

People have traditionally turned to sports drinks such as Gatorade to replenish electrolytes. But coconut water may be better because it doesn’t contain the citric acid or sugar found in some beverages.

Training for a marathon or a long-distance bike race? Coconut water may be for you. But you’ll probably want to drink it — not set up an IV drip.