The impact of dietary supplement form and dosage on perceived efficacy

The purpose of this paper is to examine the impact of supplement form and dosage level on consumers’ perceptions of dietary supplement efficacy.

The authors draw upon literature on dietary supplements and accessibility–diagnosticity theory to derive their hypotheses. Hypotheses are tested through two experiments that use a 2 (supplement form: single-ingredient [SI] vs multi-ingredient [MI]) × 2 (dosage level: low vs high) factorial design.

The findings show that consumers perceive that lower dose MI supplements are more effective than lower dose SI supplements, consistent with a “more is better” heuristic. In contrast, under high doses, the supplement form effect is insignificant; that is, MI and SI supplements are perceived to be comparable in terms of efficacy.

Dietary supplements are not regulated the same way as prescription drugs. Consumers often draw inferences about supplement efficacy based on their perceptions rather than objective evidence. This may leave consumers vulnerable to potentially harmful consequences. This research has implications for designing supplement marketing efforts and public policy, which could help consumers to make informed choices when purchasing dietary supplements.

A growing awareness of the importance of maintaining a healthy lifestyle has motivated consumers of all ages to consider alternative remedies, most notably using dietary supplements. Past research offers little insight into understanding consumer reactions to dietary supplement form such as SI and MI supplements and their dosage levels. The studies reported here address this gap in research. Public policy and marketing implications are also discussed.