A California federal court has denied class certification and dismissed a complaint against Natrol Inc. on subject matter jurisdiction grounds in a putative class action challenging company claims that its L-Arginine supplements cause vasodilation to support muscularity and the immune system, among other health-related claims. Kachi v. Natrol Inc., No. 13-0412 (U.S. Dist. Ct., S.D. Cal., order entered June 19, 2014).

The plaintiff alleged that three nutritional supplements produced with L-arginine purported to increase vasodilation to increase metabolism of nitric oxide, but with the support of an expert’s report, he argued that several scientific studies show that oral arginine supplementation does not increase nitric oxide levels. The court distinguished the cited studies from those Natrol presented by pointing to the subjects of the plaintiff’s studies as “healthy populations,” while Natrol argued that its supplement could help other populations like the elderly, overweight or diabetes-afflicted. The court concluded that the plaintiff failed to satisfy the commonality and typicality requirements of Rule 23(a), which establishes class-action prerequisites.

The court also assessed whether it had subject matter jurisdiction under the Class Action Fairness Act. With 200,000 bottles of supplements sold at about $10 each, the court calculated that the amount in controversy failed to exceed the $5-million jurisdictional threshold; in addition, the court found that the parties were not diverse because all plaintiffs and defendants were California citizens. Accordingly, the court dismissed the complaint, but did so without prejudice.