This narrative review critically examines the current research on the health implications of whey protein (WP) supplementation, with a focus on potential risks and adverse effects. WP, commonly consumed for muscle building and weight loss, has been associated with various health concerns. Our comprehensive analysis involved a thorough search of multiple databases, resulting in the inclusion of 21 preclinical and human studies that collectively offer a detailed overview of WP's health impacts. The review reveals significant findings, such as WP's potential link to liver and kidney damage, alterations in gut microbiota, increased acne incidence, impacts on bone mass, and emotional and behavioural changes. These findings underscore the complexity of WP's effects on human health, indicating both beneficial and detrimental outcomes in relation to different posologies in a variety of settings. Our study suggests caution for the protein intake in situations of hepatic and renal compromised functions, as well as in acne susceptibility, while possible beneficial effects can be achieved for the intestinal microbiota, humoral and behavioural level, and finally bone and muscle mass in elderly. We emphasizes the importance of balanced WP consumption and call for more in-depth research to understand its long-term health effects. Health professionals and individuals considering WP supplementation should be aware of these potential risks and approach its use with informed caution.
Keywords: acne; bone mass; chronic intake; collateral effects; health risks; kidney damage; liver damage; physical activity; review study; sedentary individuals; whey protein.