Comprehensive review of collagen types: sources, structure, and human health applications

Collagen is a protein that helps maintain the structural integrity and functionality of connective tissue. Collagen hydrolysate, which has recently gained popularity due to its high bioavailability, has attracted attention due to its reported benefits, such as improving skin health, relieving joint pain, and reducing signs of ageing. This review aims to compile and categorize 28 well-researched and well-known, as well as less popular, types of collagens, and investigate their relationship with physiological processes and diseases. It also examines how collagen affects ageing and its potential impact on various health conditions. Collagen hydrolysate is a food ingredient known for its support of collagen synthesis and a wide range of health benefits, such as antioxidant, anti-inflammatory, and antihypertensive effects. Types I, II, and III collagen constitute 80–90 % of the human body. Collagen Types I through VII are most commonly associated with skin health, with other collagen types also playing a variety of roles in health and disease. Dietary supplements containing collagen hydrolysate have been shown to have positive effects, including reducing signs of ageing, maintaining skin health, reducing symptoms of joint disorders, and improving overall quality of life.