Generation of cyclic peptides with improved anti-Photoaging activity during the thermal processing of collagen peptides.
Cyclic peptides are making noise in the anti-photoaging research world. A team at South China University of Technology just showed that heating collagen peptides doesn’t just break them down—it actually transforms them into new, more potent cyclic forms. The result? Stronger inhibition of matrix metalloproteinase-1 (MMP-1), a key player in collagen breakdown and skin aging.
Food Chem
by Li W, Yang D, Zheng L et al.
“Generation of cyclic peptides with improved anti-Photoaging activity during the thermal processing of collagen peptides. Li W(1), Yang D(1), Zheng L(2), Zhao M(3). Author information: (1)School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, PR China. (2)School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, PR China. Electronic address: linzheng18@163.com. (3)School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, PR China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, 510650, PR China. This study explored the structural changes of collagen peptides during heat treatment under different conditions that might affect their anti-photoaging activities. Results showed that the matrix metalloproteinase-1 (MMP-1) inhibition rate of collagen hydrolysates significantly increased after heat treatment at various pH values, and its contents of Hyp (O)-containing and Gly-Pro-Xaa tripeptides significantly reduced, while cyclic dipeptides such as cyclo(LO), cyclo(FO), and cyclo(GP) were formed. Specifically, cyclo(LO) and cyclo(GP) displayed stronger MMP-1 inhibition (64.12% and 52.81%, respectively) than the linear di- and tripeptides LO, LOG, GPI and GPM (35.86%, 22.03%, 21.28% and 41.14%, respectively). This might be due to their increased conformational rigidity and strengthened hydrophobic interactions with MMP-1. Additionally, the cyclic dipeptides cyclo(PO), cyclo(LO), cyclo(AO), cyclo(SO), cyclo(FO) and cyclo(GP) significantly enhanced the viability of fibroblasts damaged by UVA. The results highlighted the cyclic form of Hyp-containing dipeptides with improved anti-photoaging activity generated upon heat treatment and its potential application in skin health. Copyright © 2026 Elsevier Ltd. All rights reserved. Conflict of interest statement: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.”
Here’s the punchline: when collagen peptides are heat-treated, their usual linear forms drop, but new cyclic dipeptides like cyclo(LO) and cyclo(GP) emerge. These aren’t just biochemical curiosities—they outperformed their linear counterparts in MMP-1 inhibition tests. Cyclo(LO) hit 64% inhibition, while cyclo(GP) landed at 53%. For comparison, the best linear peptide in the study managed only 41%.
Why does this matter? Cyclic peptides have a locked-in structure, which seems to boost their interaction with enzymes that degrade skin collagen. But there’s more. The study also found these cyclic dipeptides helped UVA-damaged fibroblast cells bounce back, hinting at a broader role in skin health research.
Key takeaway:
Heating collagen peptides under the right conditions doesn’t just destroy them—it can generate new cyclic peptides with better anti-photoaging potential.
Cyclic forms like cyclo(LO) and cyclo(GP) are worth a closer look for anyone studying skin health or peptide bioactivity.
This research gives the peptide community more tools and targets for exploring anti-aging mechanisms. Want to dive deeper? Check out our peptide research index for more on the latest breakthroughs and applications. Research teams and vendors should keep an eye on these cyclic structures—they’re not just byproducts, they might be the main event.
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