# GLP-1 Drugs in Cushing's Syndrome: Weight Down, Cortisol Unchanged

By Nora Bissett, Pricing Editor (https://glpwatchdog.org/authors/nora-bissett) | Published: 2026-08-21 | Updated: 2026-10-27

Canonical page: https://glpwatchdog.org/research/glp1-in-cushings-syndrome

> A multicenter retrospective study of 20 adults with Cushing's syndrome found weight down 10.3 kg and HbA1c down 0.5% over a median 13 months, with ACTH and cortisol levels stable throughout.

## Key points

- 20 adults with biochemically confirmed Cushing's syndrome, four different GLP-1 drugs pooled, median 13 months of follow-up.
- Weight fell 10.3 kg and BMI 4.2 kg/m2; fasting glucose and HbA1c both fell significantly.
- ACTH and cortisol remained stable, which answers the main clinical worry.
- No control group, retrospective, and blood pressure and lipids did not significantly change. Acromegaly has no comparable evidence at all.

In Cushing’s syndrome the obesity and the diabetes are consequences of cortisol excess, which makes the obvious question a nervous one: does a drug that changes metabolism disturb the hormonal picture, or the monitoring that depends on it? A multicenter retrospective study of 20 adults with biochemically confirmed Cushing’s found weight down 10.3 kg and HbA1c down 0.5% over a median 13 months, **with ACTH and cortisol levels unchanged**.[1] Twenty people is a small sample, but before this, the paper notes, the question was unexplored.

## What was measured

The study included twenty adults with biochemically confirmed Cushing’s syndrome and concurrent type 2 diabetes and/or obesity, treated for at least three months with a GLP-1 receptor agonist (liraglutide, semaglutide, tirzepatide or dulaglutide). Anthropometric, hemodynamic, metabolic, hepatic and hormonal parameters were compared before and after therapy. Median follow-up was 13 months.[1]

*Before and after GLP-1 therapy in 20 adults with Cushing's syndrome.[1]*

| Measure | Change | P |
| --- | --- | --- |
| Body weight | −10.3 ± 8.8 kg | < 0.001 |
| BMI | −4.2 ± 2.8 kg/m² | < 0.001 |
| Fasting glucose | −12.1 ± 35.3 mg/dL | 0.015 |
| HbA1c | −0.5 ± 0.9% | 0.011 |
| ALT | −3.9 ± 21.4 U/L | 0.005 |
| GGT | −25.9 ± 57.3 U/L | 0.012 |
| Blood pressure, lipids | no significant change | — |
| **ACTH and cortisol** | **remained stable** | — |

Mild gastrointestinal side effects were reported in 26.3% of patients, and the drugs were described as generally well tolerated.[1]

> The stable ACTH and cortisol result is the one to remember. For someone whose disease is defined by those numbers, a weight-loss drug that leaves them alone is a different proposition from one that moves them. Until this study, the authors note, nobody had published the answer either way.

## What twenty retrospective patients cannot tell you

- There is no control group. Some of the weight and glucose change may reflect other treatment of the underlying Cushing's, which is what people with this condition are receiving.
- It is retrospective, so it reports what happened to be recorded rather than what was planned to be measured.
- Four different drugs are pooled into one group of twenty. Nothing here separates them.
- The blood pressure and lipid results showed no significant change, which matters in a condition where both are commonly deranged.
- Cushing's syndrome is managed by endocrinologists for good reason. This is information to bring to that conversation, not to act on alone. Which signs separate Cushing’s from ordinary weight gain is covered in [buffalo hump and weight loss](https://glpwatchdog.org/research/buffalo-hump-and-weight-loss).

## And acromegaly, where there is nothing

Acromegaly is routinely bracketed with Cushing’s when this question comes up, both being pituitary-driven disorders with metabolic consequences. We looked and could not find a cohort or case series reporting GLP-1 outcomes in acromegaly. Rather than let the Cushing’s result stand in for both, we say plainly that this register has nothing to report on acromegaly.

## Frequently asked questions

### Are GLP-1 drugs safe in Cushing's syndrome?

A retrospective study of 20 adults found them generally well tolerated over a median 13 months, with mild gastrointestinal side effects in 26.3% and, importantly, ACTH and cortisol levels remaining stable. That is reassuring but comes from twenty uncontrolled patients.

### Do they affect cortisol levels?

In this study, no. Hormonal parameters including ACTH and cortisol remained stable while weight and glycemic control improved. Since Cushing's is diagnosed and monitored on those values, that stability matters as much as the weight result.

### How much weight did people lose?

Body weight fell by a mean of 10.3 kg and BMI by 4.2 kg/m² over a median follow-up of 13 months. There was no control group, so some of that change may reflect treatment of the underlying condition.

### What about acromegaly?

We could not find a cohort or case series reporting GLP-1 outcomes in acromegaly. It is often paired with Cushing's in discussion of this question, but the evidence is not there.

## References

1. Iglesias P, Nobre EL, Hanzu F, et al. Efficacy and safety of GLP-1 receptor agonists in the treatment of type 2 diabetes and/or obesity in patients with Cushing's syndrome: a multicenter retrospective study. Endocrine. 2026. PMID: 41803337. https://pubmed.ncbi.nlm.nih.gov/41803337/

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Cite as: GLP Watchdog, Nora Bissett, "GLP-1 Drugs in Cushing's Syndrome: Weight Down, Cortisol Unchanged", published 2026-08-21, updated 2026-10-27. https://glpwatchdog.org/research/glp1-in-cushings-syndrome

Canonical HTML page: https://glpwatchdog.org/research/glp1-in-cushings-syndrome

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.