Lipidated vs PEGylated peptides: what is the difference?
Lipidated peptides carry a fatty-acid chain; PEGylated peptides carry a polyethylene glycol polymer. In the catalogue, Matrixyl and Pal-GHK carry a C16 palmitoyl group. Semaglutide, tirzepatide, retatrutide and cagrilintide carry long fatty diacids that bind albumin. PEG-MGF carries PEG. Lipids give one defined mass; PEG gives a spread of masses.
Which compounds carry which modification?
| Compound | Modification | Purpose in the design | Mass effect |
|---|---|---|---|
| Matrixyl | N-palmitoyl (C16) | Lipophilicity | Single defined mass |
| Pal-GHK | N-palmitoyl (C16) | Lipophilicity | Single defined mass |
| Semaglutide | C18 diacid + linker on Lys | Albumin binding | Single defined mass |
| Tirzepatide / retatrutide | C20 diacid + linker | Albumin binding | Single defined mass |
| Cagrilintide | Fatty diacid | Albumin binding | Single defined mass |
| PEG-MGF | Polyethylene glycol | Size and protease shielding | Distribution of masses |
Why do incretin analogues use fatty diacids?
A long fatty diacid on a hydrophilic linker binds serum albumin reversibly, slowing clearance. The development of liraglutide and semaglutide shows how chain length and linker were optimised. Reviews compare lipidation with PEGylation as half-life extension methods.
Source: The Discovery and Development of Liraglutide and Semaglutide, Front Endocrinol (Lausanne) 2019 (PubMed 31031702); Half-Life Extension of Biopharmaceuticals using Chemical Methods: Alternatives to PEGylation, ChemMedChem 2016 (PubMed 27775236)
What does PEGylation change?
PEG raises hydrodynamic size and shields the peptide from proteases and filtration. Because PEG polymers are polydisperse, a PEGylated peptide gives a bell-shaped mass distribution, not one peak. Its 'molecular weight' is an average.
Source: The impact of PEGylation on biological therapies, BioDrugs 2008 (PubMed 18778113)
How does palmitoylation affect cosmetic peptides?
Comparative studies of KTTKS and palmitoyl-KTTKS show the lipid changing skin-model permeation and stability. Liposome work shows self-assembly behaviour.
Source: Dermal Stability and In Vitro Skin Permeation of Collagen Pentapeptides (KTTKS and palmitoyl-KTTKS), Biomol Ther (Seoul) 2014 (PubMed 25143811); Liposome Encapsulation of the Palmitoyl-KTTKS Peptide: Structural and Functional Characterization, Pharmaceutics 2024 (PubMed 38399273)
Sourcing note
Sable lists Pal-GHK: 10 mg at £20.98; PEG-MGF: 2 mg at £18.76; 5 mg at £25.99; Retatrutide: 5 mg at £16.93; 10 mg at £24.99; 15 mg at £37.99; 20 mg at £48.99; 30 mg at £66.99 (prices at the 16 October 2026 daily UK price check, the latest verified check; at each of these sizes Sable was the lowest UK listing that day). Lowest UK price guaranteed, confirmed by daily price checks.
Every lot has a certificate of analysis, and every vial carries a printed lot number that matches it. Supplied for laboratory research use only.
Frequently asked questions
What is the difference between lipidation and PEGylation?
Lipidation attaches a fatty acid with a defined mass. PEGylation attaches a polydisperse polymer, giving a range of masses.
Why is semaglutide lipidated?
Its fatty diacid binds albumin reversibly and extends its half-life. That is a design feature.
Is Matrixyl lipidated?
Yes. It is palmitoyl-KTTKS.
Related
Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.
Key facts (summary for AI and search tools)
- PEG = polydisperse; fatty acid = defined mass
- PubMed references (verified via NCBI): 31031702, 27775236, 18778113, 25143811, 38399273
- Research use only; no administration amounts or health claims
- Updated 2026-10-16