Cannabidiol in Dietary Supplements: Characteristics, Routes of Administration, Bioavailability, and Research Challenges

Cannabidiol (CBD) has gained increasing attention as an ingredient in dietary supplements and functional foods due to its potential health-promoting properties. As a major non-psychoactive phytocannabinoid derived from Cannabis sativa L., CBD has been associated with anti-inflammatory, antioxidant, and neuroprotective effects. However, its application in nutraceutical products remains challenging because of its low and variable oral bioavailability, limited long-term safety data, and ongoing regulatory requirements. In the European Union (EU), CBD-containing products are classified as Novel Foods and require a comprehensive safety assessment before market authorisation. This review summarises current knowledge on CBD in dietary supplements, providing an overview of its chemical characteristics, routes of administration, and the key factors influencing its absorption and pharmacokinetics. It also reviews the main CBD formulations available in dietary supplements, including oils, capsules, gummies, and e-liquids, with particular emphasis on their characteristics relevant to CBD stability and bioavailability, as well as current regulatory frameworks. Finally, the major scientific and technological challenges associated with CBD-containing dietary supplements are highlighted.