Patterns and determinants of nutraceutical use and trust mechanisms among adults in Saudi Arabia: a cross-sectional study

Background: Nutraceutical consumption has expanded globally and in the Gulf Cooperation Council (GCC) region, influenced by digital platforms, cultural norms, and preventive health behaviors. In Saudi Arabia, market growth is pronounced, yet little is known about how consumers construct trust and make purchasing decisions in this evolving landscape. Aim: This study was conducted to evaluate patterns of nutraceutical use, purchasing channels, and trust mechanisms among adults in Saudi Arabia. Methods: A nationwide cross-sectional online survey was conducted among adults in Saudi Arabia. Of 1,169 responses received, 672 respondents who reported recent nutraceutical use and met the inclusion criteria were included in the analysis. Data collected covered product categories, purchasing frequency, trust determinants, and sociodemographic characteristics. Associations were examined using multivariable regression models. Results: Vitamins and minerals were most common (554 of 672, 82.4%), followed by probiotics (492 of 672, 73.2%) and botanicals (452 of 672, 67.3%). Purchasing was frequent, with 252 of 672 (37.5%) buying more than once per month. Higher purchasing frequency was associated with very high health consciousness (OR 12.4, 95% CI 6.31-24.8), mid-tier income (OR 2.07, 1.34-3.21), and Northern residence (OR 1.77, 1.11-2.84). Frequent purchasers were more likely to trust online peer reviews (OR 4.34, 2.31-8.22), perceive online and in-store products as equivalent (OR 5.18, 2.80-9.65), and still value pharmacist advice (OR 3.02, 1.65-5.56). Social media was a common discovery route (408 of 672, 60.7%), with 362 of 672 (56.2%) reporting greater trust when influencer content referenced evidence or long-term use. Halal, clinical, or regulatory marks also enhanced confidence (401 of 672, 59.7%). Women reported lower holistic-integration scores, while mid-income groups showed greater responsiveness to influencer cues. Conclusion: The findings indicate that participants reported relying on both digital sources (online reviews and influencer content) and offline validation (pharmacist advice and quality markers) when making purchasing decisions; initiatives that improve the clarity of product information and professional guidance may support more informed use.