(CNN) -- Thirteen deaths have been reported to the Food and Drug Administration as "adverse events" after the consumption of the dietary supplement 5-hour ENERGY, according to an FDA statement.
While anyone can report an adverse event, and although no cause-and-effect relationship has been established, the FDA said it is investigating, as is required by law. A report does not mean a product is responsible for or that it contributed to any health issue.
"If we find a relationship between consumption of the product and harm, FDA will take appropriate action to reduce or eliminate the risk," the FDA said. "While the FDA investigates all reports to the best of its ability, it does not always have access to all the information needed to conclusively determine the cause of the event."
As a dietary supplement, 5-hour ENERGY is not required to disclose the amount of caffeine in its 2-ounce "energy shot." Instead, the 5-hour ENERGY label lists 1,870 milligrams of an "Energy Blend," which includes caffeine, taurine and other ingredients.
A ConsumerLab.com analysis found about 207 milligrams of caffeine in one 5-hour ENERGY. Red Bull, by comparison, contains about 80 milligrams of caffeine in an 8.4-ounce can, while a 16-ounce grande Starbucks Pike Place brewed coffee contains about 330 milligrams of caffeine.
The distributor of 5-hour ENERGY, Living Essentials LLC, said in a statement: "We recommend on product labels and the 5-hour ENERGY website that individuals consume no more than two bottles of 5-hour ENERGY shots per day, spaced several hours apart. Consumers who have caffeine sensitivities should consult with a physician before taking and can consider the 'decaf' version."
Last month, the parents of Anais Fournier, 14, filed a lawsuit alleging that she died after drinking two Monster Energy drinks in a 24-hour period. In her case, an underlying heart condition was complicated by caffeine toxicity, according to the death certificate.
Whether the 13 deaths preliminarily linked to 5-Hour ENERGY were similarly complicated by other medical conditions is under investigation.
In addition to the deaths, there have been a total of 92 patient reports, including 33 hospitalizations, reported as 5-Hour ENERGY adverse events, according to the FDA.