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Guide · Updated October 16, 2026

503A vs 503B Compounding Pharmacies Explained

Plain-language guide to the difference between 503A patient-specific compounding pharmacies and 503B FDA-registered outsourcing facilities.

EducationalUpdated October 16, 2026
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Editorial team
Dr. Sam Saberian · Lead Medical Researcher
Medical review by Alen A. Schwartz, MD · Edited by Julliana Edwards · Last updated October 16, 2026

Overview

Plain-language guide to the difference between 503A patient-specific compounding pharmacies and 503B FDA-registered outsourcing facilities.

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Questions readers ask

Which compounding pharmacies does NexLife use?

NexLife’s plan pages name three 503A pharmacies: Absolute Pharmacy in Lutz, Florida, Premium Compounding in Decatur, Alabama, and Boudreaux’s New Drug Store in Lake Charles, Louisiana.

Is medication from a 503B facility FDA-approved?

No. 503B outsourcing facilities are FDA-registered and FDA-inspected and follow cGMP, but compounded medications from either 503A or 503B pathways are not FDA-approved drugs. Only manufactured brands such as Wegovy or Zepbound carry FDA approval.

Who oversees a 503A compounding pharmacy?

A 503A pharmacy is state-licensed and overseen by the state pharmacy board. It compounds patient-specific preparations under valid prescriptions and follows USP <797> sterile compounding standards.

Can a compounding pharmacy make retatrutide?

No. Retatrutide and cagrilintide cannot be used in compounding, whether at a 503A pharmacy or a 503B facility, so offers of compounded retatrutide should be treated as a warning sign.

Primary sources

  1. FDA: Concerns with unapproved GLP-1 drugs used for weight loss (current as of October 1, 2026)
  2. FDA: Policies for compounders as GLP-1 supply stabilizes (updated April 1, 2026)
  3. FDA: Compounding and the FDA — questions and answers
  4. FDA: Registered outsourcing facilities (503B)
  5. Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med 2021
  6. Wegovy (semaglutide) prescribing information, Novo Nordisk