Can a 60-year-old diet pill work for years? new study aims to find out.

NCT ID NCT05176626

Ongoing Disease control Sponsor: Wake Forest University Health Sciences Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study tests whether the weight-loss drug phentermine, currently approved for only 12 weeks, can be safely used for up to 2 years. About 870 adults with obesity will take phentermine and receive online lifestyle coaching. Researchers will track weight loss, blood pressure, and other health measures to see if long-term use is effective and safe.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: phentermine
What this could lead to: If successful, this could show that phentermine is safe and effective for long-term weight management, supporting its use beyond the current 12-week limit.
What could go wrong: This is a Phase 4 trial, but phentermine has known risks like increased blood pressure and heart rate. Long-term safety data are still limited, and weight loss may not be sustained in all participants.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

Obesity obesity disorder Weight Loss

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

LIFESTYLE, HEALTHY OBESITY OBESITY; DRUG

Contacts and locations

Locations

Atrium Health Wake Forest Baptist Weight Management Center

Winston-Salem, North Carolina, 27104, United States
HealthPartners Institute

Saint Louis Park, Minnesota, 55416, United States
Kaiser Permanente Southern California

Los Angeles, California, 90034, United States
UT Center for Obesity Medicine and Metabolic Performance

Bellaire, Texas, 77401, United States

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