Table 2.

Patented formulations, botanical or chemical of medications from the included studies

Study	Formulation	Source	Component	Quality control reported? (Y/N)	Chemical analysis reported? (Y/N)
Benito 2009	Colnatur (Protein SA, Girona, Spain), a powdered hydrolyzed natural collagen with a mean molecular weight of 3,500 Da; 10 g hydrolyzed collagen for once-daily administration dissolved in a liquid of the patient’s choice	Colnatur (Protein SA, Girona, Spain)	natural hydrolyzed collagen	N	N
Chen CC 2023	Essence of Chicken-hydrolyzed collagen type II doses: 2.0 g of hydrolyzed collagen type II collagen and 5.81 g of Essence of Chicken with proteins and peptides/hydrolyzed collagen type II doses: 2.0 g of hydrolyzed collagen type II collagen	Suntory Beverage and Food Asia (Changhua Taiwan, Good Hygiene Practice certified)	Hydrolyzed collagen type II: derived from chicken sternal cartilage; Essence of Chicken: extracted from chicken meat	N	Y
JX jiang 2014	Hydrolyzed collagen bovine 100%	Peptan B 2000,Rousselot	Food grade Bovine Collagen Peptides	Y	N
Trč T 2011	10 g enzymatic hydrolyzed collagen	Colatech® (trade name, uncertain company)	Enzymatic hydrolyzed collagen	N	N