Recently, scientists looked into whether a range of supplements used as weight loss or workout aids may actually be harmful to those who take them.
Yet despite the fact that higenamine is banned by the WADA, and that it might be harmful to people's cardiovascular health, many dietary supplements still contain it as a substance that naturally occurs in certain plants, such as aconite.
The researchers — including John Travis, a senior research scientist at NSF International in Ann Arbor, MI — have revealed not only that higenamine is a widely used supplement ingredient, but also that companies that produce such supplements do not properly list the dosage at which this ingredient is used.
"We're urging competitive and amateur athletes, as well as general consumers, to think twice before consuming a product that contains higenamine," says Travis.
"Beyond the doping risk for athletes," he adds, "some of these products contain extremely high doses of a stimulant with unknown safety and potential cardiovascular risks when consumed."
"What we've learned from the study is that there is often no way for a consumer to know how much higenamine is actually in the product they are taking."
These findings now appear in the journal Clinical Toxicology.
'Concerning levels' of harmful substance
The researchers analyzed 24 supplements for weight loss or preworkout that listed higenamine — also known as norcoclaurine and demethylcoclaurine — and noticed that they featured widely varying and unreliable amounts of this substance.
The 24 products tested in the study were: Adrenal Pump, Apidren, Beta-Stim, Burn-HC, Defcon1 Second Strike, Diablo, DyNO, Gnar Pump, Higenamine, High Definition, HyperMax, iBurn2, Liporidex Max, Liporidex PLUS, LipoRUSH DS2, N.O. Vate, OxyShred, Prostun-Advanced Thermogenic, Pyroxamine, Razor8, Ritual Pre-Workout Supplement, Stim Shot, ThermoVate, and Uplift.
Worryingly, of all the supplements that the researchers looked at, only five products mentioned an exact quantity of higenamine. However, when the supplements were tested, Travis and his colleagues found that the listed quantities were incorrect.
Actual quantities of higenamine across the range of products included anything from trace amounts to 62 milligrams per serving. However, based on the label instructions, users may actually take up to 110 milligrams of the substance per day, which may harm their health in unpredictable ways.
"Some plants, such as ephedra, contain stimulants. If you take too much of the stimulants found in ephedra, it can have life-threatening consequences," explains study co-author Dr. Pieter Cohen.
"Similarly," he adds, "higenamine is a stimulant found in plants. When it comes to higenamine, we don't yet know for certain what effect high dosages will have in the human body, but a series of preliminary studies suggest that it might have profound effects on the heart and other organs."
According to a study published in The New England Journal of Medicine in 2015, about 23,005 emergency department visits in the United States are related to supplement intake.
"While higenamine is considered a legal dietary ingredient when present as a constituent of botanicals, our research identified concerning levels of the stimulant and wildly inaccurate labeling and dosage information," Travis explains.
"And, as a WADA-prohibited substance," he continues, "any amount of higenamine in a dietary supplement should be of concern to the competitive athlete."
The study concludes that, to better protect consumers, the Food and Drug Administration (FDA) should now finalize their guidelines on supplement ingredients. It also warns doctors that the higenamine quantities in many dietary supplements may impact cardiovascular health.