Semaglutide Affects Blood Vessel Development in Embryonic Chicken Model | Research

The takeaway

Semaglutide altered vessel morphology in a chicken embryo membrane model, raising questions about potential vascular effects relevant to ocular and reproductive safety concerns.

2.56M monthly prescriptions
Massive semaglutide uptake makes even rare vascular effects clinically significant

What the researchers found

Semaglutide affected vessel morphology in the chicken CAM model, providing experimental evidence that may relate to reported ocular and reproductive safety signals.

Why it matters

If semaglutide affects blood vessel formation, it could explain emerging reports of eye problems (NAION) and reproductive concerns in patients, prompting more careful safety evaluation.

How the study worked

Preclinical study using chicken chorioallantoic membrane (CAM) assay to evaluate semaglutide effects on vessel development and morphology.

What this study cannot tell us

Chicken embryo model may not reflect adult human vascular biology; CAM assay is a screening tool, not definitive proof of clinical risk; dose-response relationship to human dosing unclear.

How to read the evidence

Preclinical CAM model — provides mechanistic data but limited direct applicability to human safety.

When this study was published

Published in 2026, addressing timely safety concerns about the most widely prescribed GLP-1 drug.

The bigger picture

This provides a mechanistic basis for safety concerns — if GLP-1 drugs alter blood vessel development, it could affect any organ with active angiogenesis, including eyes, placenta, and healing tissues.

Questions still open

Are semaglutide's vascular effects reversible or do they persist after drug discontinuation?
Should women planning pregnancy avoid semaglutide due to potential effects on placental angiogenesis?

Common questions

Does semaglutide affect blood vessels?

This experimental study showed semaglutide altered blood vessel development in a chicken embryo model. Whether this translates to meaningful vascular effects in adult humans is still being investigated.

Should I be worried about eye problems on semaglutide?

Reports of eye issues like NAION are very rare. This study provides a possible mechanism (vascular effects) but doesn't prove semaglutide causes eye problems in humans. Discuss any vision changes with your doctor.

Read the original research

Effects of semaglutide on vessel morphology: Studies on the chicken chorioallantoic membrane.

Microvascular research, 163, 104880

View on PubMed ↗Publisher’s paper ↗

Citation

Chen, Pei-Hsuan; Abood, Samar; Bloom, Steven. (2026). Effects of semaglutide on vessel morphology: Studies on the chicken chorioallantoic membrane.. Microvascular research, 163, 104880. https://doi.org/10.1016/j.mvr.2025.104880