Researchers Question Enzyte Safety

CHICAGOResearchers from Loyola University found healthy men who used the dietary supplement Enzyte, marketed for male enhancement," had changes in certain electrocardiographic (ECG) parameters, and questioned the safety of the product (Arch Intern Med. 2010;170(15):1402-1404. DOI: 10.1001/archinternmed.2010.254). In their research letter, the team first notedincorrectlythat supplements are sold without regulatory oversight." They sought to assess the supplements effects on QT and corrected QT (QTc) intervals.

While 50 subjects were approached for recruitment, 37 men declined and four were excluded. The remaining nine subjects were randomized for the crossover trial to receive a placebo or an active capsule containing the contents of one-half of a pulverized Enzyte immediate-release tablet. Following ingestion of the active compound, the QTc interval increased by 8.4 percent at three hours after dosing and 11 percent at five hours. There were no other ECG changes, nor arrhythmias; the subjects did report a prolonged erection. The research team noted there are several limitations in the study design, including the population of healthy menoften not the target of men with erectile dysfunction issues, and not studying whether Enzyte impacted cardiovascular mortality. They suggest more studies are needed to establish the safety of the supplement, and that clinicians should advise against its use until that time.

Accompanying the research letter was an invited commentary" on the safety of dietary supplements by Paul Shekelle, M.D., of RAND Corp. (Arch Intern Med. 2010;170(15):1404-1405. DOI: 10.1001/archinternmed.2010.291). Shekelle acknowledged the wide use of dietary supplements, but cited concerns with products including ephedra and kava, and ongoing issues with adulteration of dietary supplements with pharmaceutical actives. He said the new Enzyte study adds to the list of concerns" about supplements, despite noting the limitations in the study population and length of intervention. That said, he agreed with their assessment to avoid using the product until its safety is proven.

Shekelles commentary notes a key tenet of the Dietary Supplement Health & Education Act (DSHEA) is that dietary supplements are presumed safe" until proven otherwise; he suggests evidence suggests this is not the case and, to protect public safety, may need to be revised. He does mention the inherent challenge with trying to put supplements into the risk/benefit ratio seen with prescribing pharmaceuticals, as supplements cannot treat medical conditions, only make structure/function claims. However, if products have no proven benefit, any risk from a supplement would be considered enough to warn against its use. He wrapped up by urging dietary supplement manufacturers to do more" to convince the public of their products safety and efficacy, which could help consumer confidence and drive out less reputable players.