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perceived product benefits, reducing perceived barriers to online purchasing, and
strengthening responsiveness to platform-generated cues to action. At the same time, the
psychological pressure associated with FOMO and algorithm-driven information overload
may distract individuals or weaken their ability to critically evaluate and regulate their
health-related consumption behaviors.
Therefore, this study conceptualizes FOMO as a psychological mechanism amplified
by digital platform environments and proposes that FOMO may influence several
components of the Health Belief Model, thereby affecting Vietnamese Gen Z’s intention
to purchase dietary supplements online.
Based on the above arguments, the following hypotheses are proposed:
H1: FOMO positively influences perceived susceptibility.
H2: FOMO positively influences perceived severity of health consequences.
H3: FOMO positively influences perceived benefits of purchasing dietary
supplements online.
H4: FOMO negatively influences perceived barriers to purchasing dietary
supplements online.
H5: FOMO negatively influences self-efficacy.
H6: FOMO positively influences cues to action for purchasing dietary supplements.
2.2.2. The impact of eHBM constructs on purchase intention
Within the extended Health Belief Model (eHBM), behavioral intention is shaped by
individuals’ cognitive evaluations of perceived susceptibility, perceived severity, perceived
benefits, perceived barriers, self-efficacy, and cues to action. In digital consumption
environments, exposure to health information, user reviews, and promotional content on
e-commerce and social media platforms may further influence these perceptions and
stimulate purchase intention for dietary supplements (Mustikasari et al., 2025); (Neha et
al., 2025).
Specifically, perceived susceptibility and perceived severity encourage preventive
behaviors when individuals believe that health risks are likely and may lead to serious
consequences (Li et al., 2020); (Vogel et al., 2021). Perceived benefits represent
consumers’ beliefs about the effectiveness of dietary supplements in improving or
protecting health and are often strong predictors of usage intention (Limbu & Gautam,
2023). Conversely, concerns regarding product authenticity, safety, or cost may form
perceived barriers that reduce consumers’ willingness to purchase (Zhu et al., 2003).
Self-efficacy reflects consumers’ confidence in their ability to search for and
evaluate health information and complete online purchasing processes (Yuen et al.,
2023). Finally, cues to action, such as online reviews, influencer recommendations, or
platform-generated suggestions, may act as behavioral triggers encouraging purchase
decisions (Febian et al., 2021).
Based on the eHBM framework and prior empirical evidence, the following
hypotheses are proposed:
H7: Perceived susceptibility positively influences purchase intention.
H8: Perceived severity positively influences purchase intention.
H9: Perceived benefits positively influence purchase intention.
H10: Perceived barriers negatively influence purchase intention.
H11: Self - efficacy positively influences purchase intention.
H12: Cues to action positively influence purchase intention.
Based on the hypotheses developed, the proposed research model for this study is

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