Pharmacokinetic modeling and molecular dynamics simulations revealed how oral semaglutide is absorbed in the stomach via SNAC enhancer, explaining the fasting requirement and variable bioavailability.
~1% bioavailability explainedMolecular simulations reveal SNAC creates local pH changes protecting semaglutide in the stomach, explaining why only ~1% reaches the bloodstream
What the researchers found
Molecular dynamics revealed SNAC creates local pH changes that protect semaglutide from degradation and promote gastric transcellular absorption, explaining fasting requirements and variable bioavailability.
Why it matters
Understanding how oral semaglutide works at the molecular level enables design of better oral peptide formulations with higher bioavailability — potentially making oral GLP-1 drugs as effective as injections.
The numbers in context
Semaglutide is absorbed mainly from the stomach. It's a lipid-modified alpha-helical peptide. Structural parameters were incorporated into pharmacokinetic models.
How the study worked
Pharmacokinetic population modeling of oral semaglutide absorption. Molecular dynamics simulations of semaglutide-SNAC-gastric membrane interactions. Bioavailability analysis.
Who was studied
N/A — computational pharmacokinetic modeling study
What this study cannot tell us
Simulations are theoretical predictions. In vivo absorption involves additional complexity. Individual patient variability in gastric pH and motility affects real-world absorption.
How to read the evidence
Moderate evidence: combined PK modeling and molecular dynamics providing mechanistic understanding supported by clinical pharmacokinetic data.
When this study was published
Published in 2025. Advances understanding of the first commercially successful oral peptide drug.
The bigger picture
Oral delivery of peptides was considered impossible until oral semaglutide proved it could work. Understanding the exact mechanism at the molecular level is essential for improving bioavailability and developing oral versions of other peptide drugs.
Questions still open
- Can the SNAC mechanism be optimized to increase oral semaglutide bioavailability beyond 1%?
- Could molecular dynamics guide design of better enhancers for other oral peptide drugs?
- Would higher bioavailability oral formulations eliminate the need for fasting?
Common questions
Why must I take oral semaglutide on an empty stomach?
Why is oral semaglutide bioavailability so low?
Read the original research
Oral absorption of semaglutide: pharmacokinetic modeling and molecular dynamics simulations.
In silico pharmacology, 13(2), 103
Citation
Agarwal, Palak Nitin; Haworth, Ian S. (2025). Oral absorption of semaglutide: pharmacokinetic modeling and molecular dynamics simulations.. In silico pharmacology, 13(2), 103. https://doi.org/10.1007/s40203-025-00393-7