Compounded Semaglutide: What It Is, How It Works, and What to Know Before You Start

What Compounded Semaglutide Actually Is

Compounded semaglutide is a semaglutide product made by a compounding pharmacy instead of Novo Nordisk, the company behind the FDA-approved semaglutide medicines: Ozempic injection and Ozempic tablets, Rybelsus tablets, Wegovy injection and Wegovy tablets [5][6][7][8][2][9]. FDA states that compounded drugs are not FDA approved and are not reviewed for safety, effectiveness or quality before they are marketed [1].

The ingredient itself can differ. FDA says semaglutide sodium and semaglutide acetate salts are different active ingredients from the semaglutide in the approved drug, with no lawful basis for use in compounding that the agency is aware of [1].

FDA had received 990 adverse event reports for compounded semaglutide as of 2026-05-31 and says that figure likely undercounts [1]. The reports include dosing errors: patients measuring the wrong dose from a vial, clinicians miscalculating, and doses above what the label calls for [1].

Is Compounded Semaglutide Still Legal?

For state-licensed pharmacies and physicians, FDA's period of enforcement discretion for compounding semaglutide injection ended after a court denied the compounders' injunction request on 2025-04-24; for outsourcing facilities, FDA said it would not act on certain violations until 2025-05-22 [4]. FDA says semaglutide does not currently appear on the list of bulk substances outsourcing facilities may compound with [4].

What remains is narrower. Compounding for an individual patient requires a prescription [4]. For products that are essentially copies of a commercially available drug, FDA says it does not intend to take action when a compounder fills four or fewer prescriptions for that product in a calendar month [4]. A prescriber's documented determination that the compounded product contains a change that produces a significant difference for an identified individual patient is the other exception FDA describes [4].

Adding another ingredient does not escape that rule automatically. FDA says a product combining semaglutide with vitamin B12 may still count as essentially a copy when it uses the same route and each strength is within 10% of the commercial product [4].

On 2026-04-30 FDA proposed excluding semaglutide, tirzepatide and liraglutide from the list of bulk substances outsourcing facilities may compound with, finding no clinical need; comments were due 2026-06-29 and no final decision had been made [10].

How Semaglutide Works

Semaglutide is a GLP-1 receptor agonist: a GLP-1 analogue with 94% sequence homology to human GLP-1 that binds and activates the GLP-1 receptor, including receptors in brain areas that regulate appetite and calorie intake, and delays gastric emptying [2]. The label gives its half-life as about 1 week, and Wegovy injection is dosed once weekly [2]. The Ozempic label adds that semaglutide stimulates insulin secretion and lowers glucagon secretion in a glucose-dependent manner [9].

That description applies to semaglutide as it appears in the approved products. What sits in a given compounded vial is a separate question, because FDA does not review compounded drugs for safety, effectiveness or quality before they are marketed [1]. A 2026 laboratory study compared samples of compounded semaglutide and liraglutide with the originator products and found different impurity profiles, including amino acid deletions and additions and unidentified impurities, plus differences in strength, total impurities and high-molecular-weight protein level after light exposure; the authors concluded those impurities could increase the potential for an immune response [11].

What the Weight-Loss Evidence Shows

The trial results quoted for semaglutide come from studies of once-weekly semaglutide 2.4 mg, not of compounded products.

• STEP 1: 1,961 adults with obesity or overweight and no diabetes, 68 weeks; mean weight change -14.9% on semaglutide 2.4 mg vs -2.4% on placebo, and 86.4% vs 31.5% lost at least 5% of body weight [3].
• SELECT: 17,604 adults with established cardiovascular disease and a BMI of 27 or more but no diabetes; cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 6.5% vs 8.0% (HR 0.80) over a mean follow-up of 39.8 months [12].
• STEP 4: after 20 weeks on semaglutide, 803 adults either continued it or switched to placebo for 48 weeks; weight changed -7.9% vs +6.9% [13].
• STEP 1 extension: a year after stopping, participants regained 11.6 of the 17.3 percentage points they had lost, for a net loss of 5.6% [14].

We found no clinical trial that measured weight loss with compounded semaglutide.

Who the Labeled Product Is For

Wegovy injection is labeled, with a reduced-calorie diet and more physical activity, to reduce excess body weight and maintain weight reduction long term in adults and children aged 12 and older with obesity, and in adults with overweight plus at least one weight-related condition; it also carries indications for cardiovascular risk reduction in adults with established cardiovascular disease and obesity or overweight, and for noncirrhotic MASH with moderate to advanced fibrosis [2]. The Wegovy label says use with another semaglutide-containing product or any other GLP-1 receptor agonist is not recommended [2].

Contraindications in the Wegovy label are a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2, and a prior serious hypersensitivity reaction to semaglutide or an excipient [2].

Side Effects and Label Warnings

Wegovy carries a boxed warning about thyroid C-cell tumors seen in rodents at clinically relevant exposures; whether semaglutide causes them in humans is unknown [2].

In pooled trials of Wegovy 2.4 mg in adults with obesity or overweight (2,116 on semaglutide, 1,261 on placebo, up to 68 weeks), the common reactions were nausea 44% vs 16%, diarrhea 30% vs 16%, vomiting 24% vs 6% and constipation 24% vs 11%; 6.8% vs 3.2% stopped treatment because of adverse reactions [2].

Other labeled warnings include acute pancreatitis, with the label directing that the drug be discontinued if pancreatitis is suspected; acute gallbladder disease, with cholelithiasis in 1.6% vs 0.7%; hypoglycemia when combined with insulin or a sulfonylurea; acute kidney injury from volume depletion; severe gastrointestinal reactions, with the drug not recommended in severe gastroparesis; serious hypersensitivity including anaphylaxis and angioedema; diabetic retinopathy complications; and a mean resting heart rate increase of 1 to 4 beats per minute [2]. The label also warns about pulmonary aspiration during general anesthesia or deep sedation and tells patients to inform the surgical team of planned procedures [2].

For compounded products specifically, FDA has reported dosing errors [1], and a published case report described swelling of the lips, tongue and throat four hours after a first injection of compounded semaglutide given at a ten-fold higher dose (2 mg) than intended for a starting dose; that patient required intubation and mechanical ventilation [15].

Handling and Storage Points From FDA

FDA generally recommends that a vial of a multi-dose sterile medicine be used within 28 days of first use, and says to discard it at 28 days even if medication remains, regardless of what the compounder's instructions say [1]. A new sterile needle and syringe should be used for each dose [1]. FDA also advises against using any injectable GLP-1 drug that arrives warm or with insufficient refrigeration, because quality can be affected [1].

HealthRX.com offers compounded semaglutide by prescription.