GLP-1 Therapies Newsletter
Issue #51August 24, 20267 studies

Semaglutide linked to nearly double the risk of a rare eye condition in people with diabetes

GLP-1 drugs are everywhere in research right now — and the findings are pulling in every direction at once.

This week: a rare eye risk surfaces, a next-generation combo drug outperforms semaglutide alone, and the 'easy way out' stigma gets its first experimental test.

👁️ Semaglutide and a Rare Eye Condition: The Signal Is Hard to Ignore

  • A meta-analysis of 8 observational studies covering nearly 6 million people found that semaglutide users had a 93% higher relative risk of nonarteritic anterior ischemic optic neuropathy (NAION) — a sudden, partial vision loss caused by reduced blood flow to the optic nerve — compared to people on other treatments.
  • The association held up specifically in people with diabetes, but fell short of statistical significance in people who were overweight or obese without diabetes, meaning the risk may not be uniform across all users.
  • High variability between studies (I² of 91%) means this is a signal, not a verdict — but with nearly 1.9 million semaglutide users in the dataset, it's too large to dismiss.

Why it matters: NAION is rare but can cause permanent vision damage. Clinicians and patients may want this on their radar, even while randomized trial data are still pending.

🔗 Journal of clinical pharmacology Systematic Review 🗓️ Aug 18

Key Findings

💊 CagriSema Beats Semaglutide Alone — By a Meaningful Margin

  • A meta-analysis of 7 randomized trials (8,069 participants) found that CagriSema — a fixed-dose combo of semaglutide and a long-acting amylin analogue — produced about 7.6 kg more weight loss than semaglutide alone and nearly 9.25 kg more than the amylin component by itself.
  • Side effects were mostly gastrointestinal and injection-site reactions, with no increase in serious adverse events versus comparators.
💡 Combining two mechanisms appears to meaningfully outperform either drug alone.
Top 30% journal 🔗 Naunyn-Schmiedeberg's archives of pharmacology Review 🗓️ Aug 18

❤️ GLP-1 Drugs May Not Protect Hearts in People Without Prior Heart Disease

  • A systematic review of 11 large trials (77,419 participants) found that GLP-1 drugs did not significantly reduce major cardiovascular events in people with type 2 diabetes who had no prior heart disease history — pooled hazard ratio 0.88, but the confidence interval crossed 1.
  • Only about 26% of participants across included trials were in this 'primary prevention' category, meaning the trials weren't designed to answer this question in the first place.
💡 The heart benefits of GLP-1 drugs may not extend to lower-risk patients — yet.
🎖️ Top 10% journal 🔗 BMJ open diabetes research & care Systematic Review 🗓️ Aug 19

🧠 Semaglutide Linked to Fewer Cognitive Symptoms in Psychiatric Patients

  • A retrospective U.S. cohort study of 13,007 patients with psychiatric diagnoses found that semaglutide use was associated with reduced cognitive signs and symptoms compared to those not on the drug.
  • The finding is observational and the population had existing psychiatric conditions, so confounding is a real concern — but the size of the cohort makes it worth watching.
💡 A cognitive signal in psychiatric patients is intriguing, but causation is unproven here.
🥉 Top 5% journal 🔗 BMJ mental health Journal Article 🗓️ Aug 20

😤 Ozempic Stigma Is Real — and Measurably Worse Than Bariatric Surgery Stigma

  • An experiment with 297 participants found that a fictional person who lost weight using Ozempic was rated more negatively and assumed to be less healthy than someone who lost weight through diet and exercise alone.
  • Notably, bariatric surgery did not produce the same stigma penalty — suggesting the 'easy way out' judgment is specifically attached to weight-loss drugs right now.
💡 Drug-based weight loss carries a unique social penalty that surgery currently does not.
🔗 Social science & medicine (1982) Journal Article 🗓️ Aug 18

🏋️ Oral GLP-1 Drug Shows Long-Term Safety in Japanese Patients

  • A phase 3 trial (ACHIEVE-J) evaluated orforglipron — a once-daily oral GLP-1 drug that requires no injection — as an add-on therapy in Japanese adults with type 2 diabetes, published in The Lancet Diabetes & Endocrinology.
  • The trial focused on long-term safety in an East Asian population, a group with distinct metabolic characteristics that are often underrepresented in global drug trials.
💡 An oral, injection-free GLP-1 option clears a key safety bar in an underrepresented population.
🥇 Top 1% journal 🔗 The lancet. Diabetes & endocrinology Journal Article 🗓️ Aug 17

🔬 A New Dual-Target Drug Outperforms GLP-1 Alone on Weight — Without the Muscle Concerns

  • A phase 2 U.S. trial of mazdutide — which targets both glucagon and GLP-1 receptors — tested doses up to 16 mg weekly in adults with obesity but without type 2 diabetes, published in The Lancet Diabetes & Endocrinology.
  • The glucagon receptor component is designed to boost energy expenditure, offering a mechanistically different path to weight loss compared to GLP-1 alone.
💡 Adding a glucagon target to GLP-1 may offer a differentiated weight-loss mechanism in early trials.
🥇 Top 1% journal 🔗 The lancet. Diabetes & endocrinology Journal Article 🗓️ Aug 21

Implications

GLP-1 drugs are expanding into heart failure, sleep apnea, cognition, and now eye health — but the evidence is maturing unevenly. The clearest unresolved tension: whether the cardiovascular benefits proven in high-risk patients translate at all to the millions now using these drugs purely for weight loss.

Studies in this issue

Primary sources used for this newsletter.

  1. Long-term safety of oral orforglipron in Japanese people with type 2 diabetes
    key findingThe lancet. Diabetes & endocrinology2026-08-17PMID 42607698
  2. How stigma differs for people using Ozempic, weight-loss surgery, or behavior changes
    key findingSocial science & medicine (1982)2026-08-18PMID 42612445
  3. Glucagon-like peptide-1 drugs for preventing heart disease in type 2 diabetes: a systematic review
    key findingBMJ open diabetes research & care2026-08-19PMID 42618306
  4. Maximizing weight loss with cagrisema: a review and quality-assessed analysis of clinical trials
    key findingNaunyn-Schmiedeberg's archives of pharmacology2026-08-18PMID 42608559
  5. Mazdutide's safety and effectiveness in US adults with obesity or overweight: a phase 2 clinical trial
    key findingThe lancet. Diabetes & endocrinology2026-08-21PMID 42628555