DPP-4 inhibitors treat type 2 diabetes by blocking the enzyme that destroys GLP-1 and GIP, the body's natural incretin peptides that control blood sugar after meals.
Minutes to hoursDPP-4 normally destroys GLP-1 within minutes of release; DPP-4 inhibitors extend its active life, improving blood sugar control after meals
What the researchers found
DPP-4 inhibitors work by blocking the enzyme dipeptidyl-peptidase IV, which normally breaks down the incretin hormones GLP-1 and GIP within minutes of their release. By preventing this degradation, DPP-4 inhibitors effectively increase the body's own GLP-1 and GIP levels, leading to improved insulin secretion, reduced glucagon release, and better blood glucose control — all in a glucose-dependent manner that minimizes hypoglycemia risk.
The first two approved DPP-4 inhibitors, sitagliptin and vildagliptin, demonstrated good efficacy and tolerability as oral medications for type 2 diabetes. Additional DPP-4 inhibitors were under review or in clinical development at the time of publication.
Why it matters
DPP-4 inhibitors represent a key intersection of peptide biology and diabetes treatment. Rather than injecting synthetic GLP-1 (like semaglutide or liraglutide), these oral drugs work by protecting the body's own incretin peptides from enzymatic destruction. Understanding how DPP-4 destroys GLP-1 and GIP — and how inhibiting this enzyme restores their function — is fundamental to understanding the entire incretin-based approach to diabetes treatment that has transformed the field.
The numbers in context
2 approved DPP-4 inhibitors at time of publication (sitagliptin, vildagliptin) · 2 additional under regulatory review · Multiple others in clinical development · Oral administration · Target: DPP-4 enzyme that degrades GLP-1 and GIP
How the study worked
Expert review article covering the mechanism of action, development history, and physiological effects of DPP-4 inhibitors in the context of type 2 diabetes treatment. Published in Best Practice & Research Clinical Endocrinology & Metabolism.
Who was studied
Not applicable (review article on drug mechanism of action)
What this study cannot tell us
Published in 2009, this review covers only the early DPP-4 inhibitor landscape. Long-term safety data, cardiovascular outcomes, and comparisons with GLP-1 receptor agonists were not yet available. The review predates the explosion of GLP-1 agonists for obesity and cardiovascular protection that would later overshadow DPP-4 inhibitors in some clinical contexts.
How to read the evidence
This is an expert review from a respected endocrinology journal. The underlying science on DPP-4 enzyme activity and incretin biology is well-established. The clinical efficacy of DPP-4 inhibitors has since been extensively confirmed in large trials.
When this study was published
Published in 2009. The DPP-4 inhibitor class has since expanded to include saxagliptin, linagliptin, and alogliptin. The mechanism of action described remains accurate and unchanged.
The bigger picture
DPP-4 inhibitors were the first practical application of incretin biology in diabetes treatment. They paved the way for the GLP-1 receptor agonist revolution by proving that enhancing the incretin system could effectively treat type 2 diabetes. While GLP-1 receptor agonists have since taken center stage (especially for weight loss and cardiovascular protection), DPP-4 inhibitors remain widely prescribed — particularly for patients who prefer an oral medication with a gentler side effect profile.
Questions still open
- Why do GLP-1 receptor agonists produce greater weight loss and cardiovascular benefits than DPP-4 inhibitors, despite both working through the incretin system?
- Could combining DPP-4 inhibitors with GLP-1 agonists provide additional benefit, or do they work on the same pathway redundantly?
- Are there other important peptides beyond GLP-1 and GIP that DPP-4 degrades, and what are the implications of protecting them?
Common questions
What's the difference between DPP-4 inhibitors and GLP-1 drugs like Ozempic?
Can DPP-4 inhibitors cause low blood sugar?
Read the original research
Mechanism of action of inhibitors of dipeptidyl-peptidase-4 (DPP-4).
Best practice & research. Clinical endocrinology & metabolism, 23(4), 479-86
Citation
Thornberry, Nancy A; Gallwitz, Baptist. (2009). Mechanism of action of inhibitors of dipeptidyl-peptidase-4 (DPP-4).. Best practice & research. Clinical endocrinology & metabolism, 23(4), 479-86. https://doi.org/10.1016/j.beem.2009.03.004