Retatrutide, an injectable triple-hormone receptor agonist combining glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon activity, has shown promise in ongoing phase 3 trials. To date, retatrutide is not FDA approved, yet it is being sold openly online to self-treating patients, leaving clinicians to monitor use of a drug they didn't prescribe and cannot verify for safety or dosing.

1. Access Outpaces Approval

Reportedly, more than 120 websites and at least 50 clinics currently advertise retatrutide for sale through telehealth platforms, medical spas, and compounding pharmacies at widely varying prices with no insurance coverage. Most patients discover retatrutide via social media. Some seek a source for an unapproved treatment such as retatrutide because they are unable to access approved therapies.

2. Black Market Healthcare

Retatrutide is still considered investigational, and can’t be obtained legally outside of a clinical trial. Compounding the drug is also illegal. Supply chains import bulk product (commonly from China) and repackage it under their own branding. Testing has shown wide variation in purity and dosing of drugs obtained online, with some vials containing a different substance entirely.

3. Adverse Effects Mismatch

In phase 3 trials, adverse effects of retatrutide were chiefly gastrointestinal. In contrast, a recent study of more than 13,500 social media users who claimed to be taking retatrutide revealed a different side effect profile, with the most common being increased appetite, fatigue, insomnia, and elevated heart rate. This raises questions about whether products sold outside clinical trials actually contain only the active drug retatrutide.

4. Warnings Aren’t Working

The FDA has issued letters to more than a dozen online vendors, warning them that marketing or selling unapproved retatrutide products directly to consumers is illegal. However, recipients have largely not ceased advertising and selling retatrutide, because enforcement is minimal at this point.

5. What Can Clinicians Do?

Because prescribers cannot verify the source, purity, or dosing of retatrutide, clinicians can counsel patients to wait for FDA approval. When appropriate, offer an FDA approved alternative, such as a GLP-1 or GLP-1/GIP receptor agonist. For patients who continue retatrutide despite counseling, monitor liver and kidney function and complete blood count, and reinforce the risks of excessive weight loss, including lean muscle loss, gallstones, and nutritional deficiencies.

Bottom Line

The supply of retatrutide has already outpaced oversight, and patients using it may not know what they are actually taking. Clinicians should seek to engage patients in conversations about using an unapproved drug, counsel them on the risks, and offer approved alternatives where appropriate. For patients who continue taking retatrutide regardless of warnings, lab monitoring and counseling on rapid or excessive weight loss remain the most practical safeguards.

This article is based on a recent Medscape feature titled " Unapproved Retatrutide Use Challenges Clinicians” and was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.