What You Need to Know About GLP-1 Agonist Side Effects?

GLP-1 agonist side effects explained: GI issues, hair loss, ED, and more—separating myths from evidence-based facts.

Overview

Patients are asking about recent reports of side effects linked to GLP-1 receptor agonists (such as semaglutide), especially when used for weight loss.

These medications are known to cause gastrointestinal side effects, including nausea and constipation. As their use expands, additional potential risks continue to be evaluated. Clinicians should stay informed about emerging safety information and help patients weigh the benefits and risks when considering treatment.

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New GLP-1 Agonist Side Effect

Hair loss: Evidence is mixed.

Some observational studies show an association between GLP-1 receptor agonists and hair loss, but not causation. Many did not account for genetic hair loss. Nutritional changes or rapid weight loss with GLP-1 therapy may also contribute and may be reversible.

A small number of reports suggest GLP-1s may improve hair growth in some cases, though evidence is still evolving.

For now, advise patients to monitor for hair loss, address nutritional factors if it occurs, and consider standard treatments (e.g., minoxidil) as part of shared decision-making.

Erectile dysfunction (ED): Mostly a rumor.

Only a few observational studies suggest a possible link between GLP-1 receptor agonists and ED, while most data show a decreased risk. A small randomized trial of 24 men using dulaglutide for weight loss did not find an increase in ED.

Obesity and diabetes themselves increase ED risk, so symptoms should be treated with evidence-based therapies (e.g., sildenafil) while addressing overall metabolic health.

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Aspiration during surgery: Rumor, with conditions.

We have some evidence that peri-op patients on GLP-1 receptor agonists are more likely to have residual food in their stomach prior to surgery. But several large studies suggest GLP-1 receptor agonists do NOT increase aspiration events.

To be on the safe side, recent surgery guidelines prioritize holding GLP-1 receptor agonists for patients with high aspiration risk (Parkinson disease, etc).

Suicide: A rumor.

Multiple large studies and meta-analyses have not found an increased risk of suicide associated with GLP-1 receptor agonists, despite early safety signals and media reports.

Nonetheless, patients should be advised to report any mood changes, depression, or suicidal thoughts promptly.
If suicidal ideation occurs, immediate referral to appropriate resources is essential (e.g., 122 for police or 123 for medical emergencies in Egypt, call or text 988 in the US).

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References

Alsuwailem OA, Alanazi R, Almutairi HM, et al. Hair Loss Associated With Glucagon-Like Peptide-1 (GLP-1) Receptor Agonist Use: A Systematic Review. Cureus. 2025;17(9):e92454.
Yang B, Cheng H, Hu Y, et al. Effects of Anti-Diabetic Drugs on Erectile Dysfunction: A Systematic Review and Meta-Analysis. Diabetes Metab Syndr Obes. 2025;18:467-478.
Kindel TL, Wang AY, Wadhwa A, et al. Multisociety Clinical Practice Guidance for the Safe Use of Glucagon-like Peptide-1 Receptor Agonists in the Perioperative Period. Clin Gastroenterol Hepatol. 2025;23(12):2083-2085.
Ebrahimi P, Batlle JC, Ayati A, et al. Suicide and Self-Harm Events With GLP-1 Receptor Agonists in Adults With Diabetes or Obesity: A Systematic Review and Meta-Analysis. JAMA Psychiatry. 2025;82(9):888-895.