# GLP-1 Drugs, Diabetic Foot Ulcers and Blood Flow to the Foot

By Nora Bissett, Pricing Editor (https://glpwatchdog.org/authors/nora-bissett) | Published: 2026-08-21 | Updated: 2026-10-30

Canonical page: https://glpwatchdog.org/research/glp1-diabetic-foot-ulcers-and-perfusion

> A randomized trial found liraglutide raised oxygen reaching the skin of the lower limb, with 89% of the drug group improving against 46% of controls. A 125,150-person cohort recorded amputation in 2.34% of semaglutide users against 5.21%.

## Key points

- STARDUST, an open-label RCT in 55 people: transcutaneous oxygen pressure rose 11.2 mm Hg over 6 months against conventional treatment.
- 89% of the liraglutide group reached a 10% rise in foot oxygen, against 46% of controls; 6-minute walk improved by 25.1 m.
- In 125,150 people with diabetic foot ulcers, amputation was recorded in 2.34% of semaglutide users against 5.21% of non-users.
- No randomized trial has used ulcer healing or amputation as its endpoint. The honest description is consistent and unproven.

Among adults who have both type 2 diabetes and [peripheral artery disease](https://glpwatchdog.org/research/semaglutide-and-peripheral-artery-disease), six months of liraglutide raised the oxygen reaching the skin of the lower limb. Eighty-nine percent of the drug group hit a 10% improvement in transcutaneous oxygen pressure, against 46% on conventional risk-factor treatment.[1] That is a mechanism, measured with an instrument. Separately, a cohort of 125,150 people with diabetic foot ulcers found amputation recorded in 2.34% of semaglutide users against 5.21% of non-users. That is an association only, and the study’s authors say plainly that causation cannot be inferred.[2]

## The randomized half: oxygen reaching the foot

STARDUST enrolled 55 people in Naples with type 2 diabetes, peripheral artery disease and a transcutaneous oxygen pressure between 30 and 49 mm Hg, the band where perfusion is impaired but the limb is not yet critically threatened. They were randomized to 1.8 mg liraglutide or conventional treatment of cardiovascular risk factors for six months.[1]

*STARDUST, 6 months, liraglutide against conventional treatment.[1]*

| Measure | Result | 95% CI |
| --- | --- | --- |
| Transcutaneous oxygen pressure | +11.2 mm Hg | 8.0 to 14.5 (P < .001) |
| Reached a 10% rise in TcPo₂ | **89% vs 46%** | RR 1.91 (1.26–2.90) |
| 6-minute walking distance | +25.1 m | 21.8 to 28.3 (P < .001) |
| C-reactive protein | −0.4 mg/dL | −0.7 to −0.07 |
| Urinary albumin-to-creatinine ratio | −119.4 mg/g | −195.0 to −43.8 |

Walking distance is the row a patient would notice most, because it is the one they would feel: twenty-five meters further in six minutes. A far larger semaglutide trial, STRIDE, [measured walking distance in 792 people over a year](https://glpwatchdog.org/research/how-far-you-can-walk).

> **STARDUST was open-label**, so everyone knew who was getting the drug. That matters less for an oxygen electrode than for a symptom questionnaire, but the six-minute walk is effort-dependent and unblinding can move it. Fifty-five people at a single Italian center is also a small trial.

## The observational half: what happened to the feet

A retrospective cohort drew on the TriNetX US research network across 64 healthcare organizations, comparing 6,329 semaglutide users who had a diabetes-related foot ulcer against 118,821 non-users, matched on age, sex, race and ethnicity. Within one year:[2]

*One-year outcomes, semaglutide users vs non-users with diabetes-related foot ulcers.[2]*

| Outcome | Semaglutide | No semaglutide |
| --- | --- | --- |
| **Amputation** | **2.34%** | **5.21%** |
| Chronic non-healing wound | 0.75% | 1.23% |
| Wound healing complications | 0.19% | 0.38% |
| Wound dehiscence | 0.26% | 0.56% |
| Chronic pain | 4.44% | 8.06% |
| Wound care | 2.42% | 4.86% |

Similar patterns held out to five years. But this is a records study, and the direction of the confounding is not obvious: people prescribed semaglutide differ from people who are not, in ways a match on age, sex, race and ethnicity does not capture. The people well enough to be started on a weekly injectable may also be the people who were going to keep their foot.

> Causation cannot be inferred due to the study’s observational design.
>
> — Lewis et al., Diabetes & Vascular Disease Research, 2025

## How to hold the two together

A trial that shows a plausible mechanism and a cohort that shows the outcome you would expect from that mechanism is a stronger position than either on its own. It is still not proof. Nobody has run a randomized trial with amputation as the endpoint, which is the study that would settle it, and until somebody does, the fair description is “consistent and unproven”.

None of this is a reason to start a GLP-1 to treat a foot ulcer. Neither drug is approved for that, ulcer care is wound care, and the people in both studies were being treated for diabetes. If you have an ulcer, the person to talk to is whoever is dressing it. Our page on [GLP-1s and your kidneys](https://glpwatchdog.org/research/glp1-and-your-kidneys) covers a diabetes complication where this class does have randomized outcome data, and the [methodology](https://glpwatchdog.org/methodology) explains how we weigh a records study against a trial.

## Frequently asked questions

### Do GLP-1 drugs help diabetic foot ulcers heal?

There is no randomized trial with ulcer healing as its endpoint. A cohort of 125,150 people found lower rates of non-healing wounds, wound complications and amputation among semaglutide users, but its authors state that causation cannot be inferred from an observational design.

### What did the randomized trial measure?

STARDUST measured transcutaneous oxygen pressure (oxygen reaching the skin of the lower limb) in 55 adults who had both type 2 diabetes and peripheral artery disease. After six months liraglutide raised it by 11.2 mm Hg against conventional treatment, and 89% of the liraglutide group reached a 10% improvement against 46% of controls.

### Does it reduce amputation risk?

The cohort study recorded amputation in 2.34% of semaglutide users against 5.21% of non-users within a year. That is an association in records data, not a trial result, and people who get a semaglutide prescription can be unlike non-users in ways the matching could not see.

### Should I take a GLP-1 for an ulcer?

No GLP-1 is approved for wound healing or peripheral artery disease, and the participants in both studies were being treated for type 2 diabetes. An active foot ulcer is a matter for the clinician managing it.

## References

1. Caruso P, Maiorino MI, Longo M, et al. Liraglutide for Lower Limb Perfusion in People With Type 2 Diabetes and Peripheral Artery Disease: The STARDUST Randomized Clinical Trial. JAMA Network Open. 2024. PMID: 38470420. https://pubmed.ncbi.nlm.nih.gov/38470420/
2. Lewis JE, Omenge DK, Patterson AR, et al. The impact of semaglutide on wound healing in diabetes related foot ulcer patients: A TriNetX database study. Diabetes & Vascular Disease Research. 2025. PMID: 40080656. https://pubmed.ncbi.nlm.nih.gov/40080656/

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Cite as: GLP Watchdog, Nora Bissett, "GLP-1 Drugs, Diabetic Foot Ulcers and Blood Flow to the Foot", published 2026-08-21, updated 2026-10-30. https://glpwatchdog.org/research/glp1-diabetic-foot-ulcers-and-perfusion

Canonical HTML page: https://glpwatchdog.org/research/glp1-diabetic-foot-ulcers-and-perfusion

Medical disclaimer: Nothing here is medical advice. We report on this subject; we do not treat anyone. Whether to begin a medication, supplement, or treatment, whether to adjust it, and whether to stop are questions for a clinician licensed to answer them, who knows your history.