Does Euonymus alatus have any effects on diabetic retinopathy?
Euonymus alatus (EA) is a shrub used in traditional Chinese medicine for diabetes. A small body of laboratory and animal research suggests that certain EA extracts, and one compound isolated from it, can reduce the abnormal blood vessel growth that drives diabetic retinopathy (DR), the eye damage caused by long-term high blood sugar. However, this evidence comes almost entirely from cells and diabetic mice, not from people, so it is too early to say whether EA helps patients.
What the research says
A 2022 study tested three EA extracts on retinal blood vessel cells grown in high glucose and on diabetic KK-Ay mice. The water extract (WEA) reduced cell migration and tube formation, two steps in new blood vessel growth, and improved ocular blood flow in the mice after 12 weeks of treatment 9. A follow-up 2024 study identified a specific EA compound, stigmast-4-en-3-one (called E6), as the active anti-angiogenic substance. In retinal endothelial cells, chicken embryos, zebrafish, and diabetic mice, E6 inhibited vascular proliferation and improved retinopathy, and its effects were compared with triamcinolone acetonide, a standard eye injection 10. Both studies point to angiogenesis (the growth of new blood vessels) as the main target, which is central to how DR damages the retina 910.
A broader 2026 review of EA's anti-diabetic mechanisms describes over 230 metabolites and several validated pathways, including inhibition of alpha-glucosidase, activation of insulin signaling, modulation of gut bacteria, and suppression of inflammatory and oxidative stress pathways 11. That review also notes that pharmacokinetic data are very limited: no classical pharmacokinetic parameters have been experimentally determined for any EA metabolite, and oral bioavailability is only predicted by computer models 11. This matters because without knowing how much of the active compounds reach the eye, it is hard to judge whether the animal findings would translate to humans.
For context, DR treatment research in humans has focused on glucose-lowering drugs and eye injections. A meta-analysis of 16 studies and over 1.7 million patients found that SGLT2 inhibitors were associated with a lower risk of DR progression (relative risk 0.77) and macular edema progression (relative risk 0.75) compared with other glucose-lowering drugs 3. Another review found that a ranibizumab port delivery system achieved visual acuity gains similar to monthly injections in diabetic macular edema 4. These human data show what proven DR therapies look like, and EA has not yet been tested at that level.
Other research has linked DR to broader health risks. A meta-analysis of nine studies and nearly 2.9 million patients found that DR is associated with a significantly higher risk of all-cause dementia 7. A separate meta-analysis found obstructive sleep apnea was not significantly tied to DR overall, though risk was doubled in Asian subgroups 8. These findings are about DR risk factors and consequences, not about EA, but they underline why controlling DR matters beyond the eye.
What to ask your doctor
- What does the current evidence say about Euonymus alatus for diabetic retinopathy, and is there any human data yet?
- Could EA interact with my diabetes medications or affect my blood sugar?
- What proven treatments are available for my stage of diabetic retinopathy, such as SGLT2 inhibitors or eye injections?
- Are there any clinical trials of Euonymus alatus or its compounds that I could join?
- How often should I have eye exams to monitor my retinopathy?
This question is drawn from common patient questions about Diabetes & Endocrinology and answered using cited medical research. We do not provide individualized advice.