The current study investigated whether commercial collagens were within physiologically acceptable limits to ensure their safer use. For this purpose, 10 of the 25 most popular collagen from fish and farm animals (FA) sold on the internet were randomly selected and purchased from a pharmacy. The zinc, lead, cadmium, mercury, and arsenic levels in these commercial products were then analyzed by ICP-OES. Streptomycin, sulfonamide, tetracycline, and chloramphenicol levels in the samples were determined by HPLC. No lead, mercury or arsenic residues were found in any of the tested samples. The mean cadmium levels in fish and FA collagen samples were not significant between the groups (P=0.2548). The lowest cadmium level in fish collagen samples was 0.152 mg/kg and the highest cadmium level was 0.288 mg/kg. Cadmium levels detected in FA collagen samples ranged from 0.183 mg/kg to 2.78 mg/kg. The mean zinc levels in fish and FA collagen were not significant (P=0.2644). The lowest zinc level in fish collagen was 1.368 mg/kg and the highest was 2673 mg/kg. The lowest and highest zinc levels in FA collagen were 1,750 mg/kg and 1528 mg/kg, respectively. According to the current results, no streptomycin, sulfonamide, and tetracycline residues were found in any of the collagen samples evaluated. Chloramphenicol was only in two fish collagen samples, but these values were below the lower detection limits. The results indicated that the risk of heavy metal and antibiotic residues in commercial collagen sold in our country is low.