The FDA's Empower Letter and the 'Essentially Copies' Rule for Compounded Semaglutide and Tirzepatide

On September 18, 2026, the FDA sent a warning letter to Empower Pharmacy, a large compounding pharmacy in Houston. The agency said Empower's compounded semaglutide and tirzepatide look like "essentially copies" of FDA-approved drugs. It said Empower made them regularly and in large amounts. It also questioned prescriptions that used the same "significant difference" wording for many patients, some of it picked from menus on third-party technology platforms.

The letter does not ban compounded GLP-1 drugs. It does not announce a recall. But it shows how the FDA reads the rules now that the national shortages of these drugs are over. It also puts pressure on the way many prescriptions for compounded GLP-1s are written.

The letter follows an FDA inspection of Empower's Houston facility from November 3 to 14, 2025. It names three products Empower made each month from July through October 2025. Two were tirzepatide combined with niacinamide (a form of vitamin B3), in different strengths. The third was semaglutide combined with cyanocobalamin (vitamin B12). The FDA blacked out the number of orders in the public letter.

The FDA's main points:

• The products "appear to be essentially copies of FDA-approved semaglutide and tirzepatide products." Empower made them "regularly and in inordinate amounts."
• Many prescriber notes claiming a "significant difference" appeared "repeated verbatim across many records." The FDA said this suggests "they may be pre-generated."
• Some prescriptions came through "third-party technology platforms that provide prescribers with pre-selected menu options." The FDA said this calls into question whether each decision was made for an individual patient.
• The FDA said the volume Empower produced suggests the differences from the approved drugs "are pretextual."

The letter also cites insanitary conditions. Smoke studies did not adequately show one-way airflow in the sterile work area. Media-fill tests, which check sterile technique, were not run under the most challenging conditions. The FDA called the products misbranded, adulterated, and unapproved new drugs. It gave Empower 15 working days to respond. It warned that failure to fix the problems could lead to legal action, including seizure and injunction.

Empower told CBS News it has "already remediated many of the issues outlined in the Warning Letter." It said it will "continue to work cooperatively with the agency to ensure patient access to quality compounded drug products." CBS also reported that Empower sells its products to health care providers, not directly to consumers.

Federal law sets up two main types of compounders, named after sections of the Federal Food, Drug, and Cosmetic Act.

A 503A pharmacy is a state-licensed pharmacy, or a licensed physician, that mixes drugs for individual patients who have a prescription. Empower's letter falls under this section. According to FDA guidance, 503A compounders are not required to follow current good manufacturing practice (CGMP) rules, and they are not licensed by the FDA and generally do not register with it.

A 503B outsourcing facility can compound drugs for patients with prescriptions or supply them to health care providers without a prescription for each patient. 503B facilities follow a separate set of rules.

In either case, a compounded drug is not FDA-approved. The FDA's guidance says that means it has not had FDA review for safety, effectiveness, or quality before it reaches patients.

Section 503A says a compounder cannot make "regularly or in inordinate amounts" any drug that is "essentially a copy of a commercially available drug product." The FDA explained how it reads those words in a January 2018 guidance.

A drug is commercially available if it is being marketed and is not listed as "currently in shortage" in the FDA's drug shortage database.

The FDA considers a compounded drug essentially a copy when it has the same active ingredient as the approved drug, in the same or a similar strength (within 10%) or one that is easy to substitute, and can be given the same way, such as by injection under the skin.

There is one main exception. A compounded drug is not a copy if the prescriber decides that a change made for a specific patient produces a "significant difference" for that patient. The guidance says this decision should be written on the prescription. Its examples are short and specific: "No Dye X, patient allergy," "Liquid form, patient can't swallow tablet," and "6 mg, patient needs higher dose." A prescription that lists only the patient's name and the formula is not enough. A lower price is not enough either.

The guidance also sets a volume line. The FDA said it does not intend to act against a compounder that fills four or fewer prescriptions for a copy in a calendar month, and each refill counts as a new prescription. Prescriptions with a documented significant difference do not count toward the four. Warning signs the FDA lists include offering pre-printed prescription pads and making the drug on a routine schedule instead of as needed.

In 2018, the FDA said it generally did not intend to question a prescriber's documented determination. The Empower letter does not question a single doctor's judgment. It questions notes that look identical across many records and were picked from menus, which suggests no individual judgment was made at all.

While a drug is on the FDA's shortage list, it is not "commercially available." So compounded versions do not count as copies. That is how compounded semaglutide and tirzepatide spread during the shortages.

The FDA declared the tirzepatide shortage over on October 2, 2024, and confirmed it on December 19, 2024. It declared the semaglutide shortage over on February 21, 2025. The agency then gave compounders time to wind down. For 503A pharmacies, that grace period ended on February 18, 2025 for tirzepatide and April 22, 2025 for semaglutide. For 503B outsourcing facilities, it ended on March 19, 2025 and May 22, 2025.

After a shortage ends, the FDA says it "generally considers the drug to be commercially available." From then on, a 503A pharmacy making these drugs in volume needs a real, patient-specific reason on each prescription. Otherwise it has to stay under the four-per-month line.

Many compounded GLP-1s come with an extra ingredient, such as vitamin B12 or niacinamide. All three of Empower's named products had one.

The letter does not say that adding a vitamin is illegal by itself. Its point is narrower. An added ingredient can support a significant-difference claim only if a prescriber decided the change matters for that patient. The FDA says the same reason repeated word for word across many prescriptions, plus high volume, makes the difference look like a pretext rather than a medical decision.

Add-ins raise other questions too. This site has covered a study on the chemistry of tirzepatide mixed with vitamin B12 in Compounded Tirzepatide and B12.

The Empower letter targets the 503A side. A separate FDA action targets 503B outsourcing facilities.

On April 30, 2026, the FDA proposed leaving semaglutide, tirzepatide, and liraglutide off the 503B bulks list, the list of raw ingredients outsourcing facilities may use to compound. The FDA said it "did not identify a clinical need" for outsourcing facilities to compound these drugs from bulk ingredients. That proposal applies only to 503B facilities. The FDA later extended the comment period to July 30, 2026. As of September 25, 2026, the Federal Register showed no final decision.

Taken together, the two actions narrow both legal paths for making large amounts of compounded GLP-1s. Darshan Kulkarni, a pharmacy and health care lawyer, told CBS News: "That avenue is definitely getting narrower."

Start with what the letter is and is not. The FDA calls warning letters "informal and advisory." They state the agency's position, but they do not commit the FDA to enforcement, and the company can respond or disagree. Empower has 15 working days to answer. The letter does not announce a recall or tell patients to stop treatment.

It is still worth asking a few questions:

• Which pharmacy fills my prescription, and is it a state-licensed 503A pharmacy or a 503B outsourcing facility?
• Does my prescription state a specific reason, tied to me, why I need a compounded version instead of the approved drug?
• If my supply changes, how will my dose be adjusted? Compounded and branded products can use different concentrations and devices, so do not switch on your own.
• What would the approved drug cost me through my insurance or a manufacturer program?

For help comparing costs, see the site's GLP-1 pricing guide for September 2026. For help judging a pharmacy, see How to Evaluate a Compounding Pharmacy.

Several questions remain open. Empower's written response is not public yet, and the FDA has not said whether it considers the problems fixed. Other large compounders could receive similar letters. The letter does not name the technology platforms it describes, so it is not clear which telehealth services or prescribing tools are affected. The 503B proposal is also still pending. Any of these could change how easy it is to get compounded semaglutide or tirzepatide over the next year.

The "essentially copies" rule has been in the law since 1997 and in FDA guidance since 2018. During the shortages it barely mattered, because a drug on the shortage list is not commercially available. Now that the shortages are over, the rule is back in force. The Empower letter shows the FDA looking past the paperwork, at whether each significant-difference note reflects a real decision about a real patient. For patients, the safest step is to know where your medicine comes from and why your prescription calls for a compounded version.