The Collagen Crisis: Why Most Adults May Be Running a Deficit They Don't Know About

Your body needs about 12 grams of glycine daily just for collagen synthesis, but can only make about 3 grams and gets 2 to 4 grams from a typical diet, leaving a notable 10-gram daily deficit in many adults This deficit isn't a disease. It's an evolutionary constraint built into human biochemistry. Our glycine synthesis pathway has a hard stoichiometric bottleneck that can never be overcome, regardless of how healthy you are Collagen makes up 25% to 30% of your total body protein, but its production is limited by glycine, which occupies every third position in the collagen chain. The procollagen quality control cycle destroys 30% to 50% of newly synthesized collagen, and some amino acids lost in this process cannot be fully recycled Over time, chronic glycine deficiency may contribute to changes in skin, joints, bones, gut lining, blood vessels, and sleep quality. Glycine deficiency has been observed across a range of conditions, including Type 2 diabetes, insulin resistance, pregnancy, and xenobiotic exposure A 2025 meta-analysis reported that collagen peptide supplementation was associated with improvements in bone and muscle health markers in the populations studied, consistent with the idea that glycine availability may have functional implications