What Is Ozempic Made Of? The Active Ingredient, the Inactive Ingredients, and How It's Manufactured

Key Takeaways

• Ozempic's active ingredient is semaglutide, a 31-amino-acid peptide modeled on a hormone the human gut already produces (GLP-1).
• A single 1 mL Ozempic cartridge contains 1.34 mg of semaglutide plus six inactive ingredients: disodium phosphate dihydrate, propylene glycol, phenol, water for injection, and small amounts of sodium hydroxide and hydrochloric acid for pH balance.
• Semaglutide is built using recombinant DNA technology in yeast cells (Saccharomyces cerevisiae), then chemically modified with a fatty acid chain that lets it bind to albumin and stay in the body for about a week.
• Ozempic does not contain insulin, animal-derived ingredients, gluten, lactose, or preservatives beyond phenol.
• The pen is sterile, multi-dose, and engineered for once-weekly subcutaneous injection at three dose strengths (0.25/0.5 mg, 1 mg, and 2 mg).

Direct answer (40-60 words)

Ozempic is made of semaglutide as the active ingredient, plus disodium phosphate dihydrate, propylene glycol, phenol, water for injection, and trace sodium hydroxide or hydrochloric acid as inactive ingredients. Semaglutide is a synthetic 31-amino-acid peptide manufactured in yeast cells through recombinant DNA technology, then attached to a fatty acid chain that extends its half-life to roughly seven days.

Table of contents

1. The 30-second answer
2. The active ingredient: what semaglutide actually is
3. The full inactive ingredient list and what each one does
4. How semaglutide is manufactured
5. What Ozempic does NOT contain
6. How the pen is engineered
7. Ozempic vs Wegovy vs Rybelsus: same molecule, different formulations
8. Allergy and sensitivity considerations
9. FAQ
10. Sources
11. Footer disclaimers

The active ingredient: what semaglutide actually is

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist. In plain language, it's a lab-made copy of a hormone your gut releases after you eat, with a few targeted changes that make it last much longer in the body.

The natural human GLP-1 hormone has a half-life of about two minutes. Enzymes called dipeptidyl peptidase-4 (DPP-4) chew it up almost as fast as the body releases it. That's fine for the natural job of GLP-1 (signaling fullness for an hour or two after a meal), but useless as a once-weekly medication.

Novo Nordisk's chemists started with the GLP-1 backbone, then made three changes (Lau et al., Journal of Medicinal Chemistry 2015):

1. They swapped the amino acid at position 8 from alanine to aminoisobutyric acid, which blocks DPP-4 from cleaving the peptide.
2. They attached an 18-carbon fatty diacid chain to the lysine at position 26. This chain binds to albumin, the most abundant protein in human blood, which carries semaglutide around like a passenger and shields it from kidney filtration.
3. They swapped lysine at position 34 to arginine, which prevents the fatty acid chain from attaching at the wrong site during manufacturing.

The result is a 31-amino-acid peptide with about 94% sequence similarity to native human GLP-1 and a half-life of roughly seven days. That's why Ozempic is dosed once weekly instead of every few hours.

Each Ozempic pen contains 1.34 milligrams of semaglutide per milliliter of solution. The actual dose delivered per injection (0.25 mg, 0.5 mg, 1 mg, or 2 mg) is set by the click-counted volume the pen dispenses, not by a different concentration in different pens.

The full inactive ingredient list and what each one does

A 1 mL cartridge of Ozempic contains:

A few notes on each:

Disodium phosphate dihydrate is the same buffering salt used in many injectable medications. It keeps the solution at pH 7.4, which matches blood. At a different pH, semaglutide can degrade or precipitate.

Propylene glycol is a tonicity agent. Cells shrink or swell if injected fluid has the wrong salt concentration relative to blood. Propylene glycol is widely used in injectables for this purpose. The amount in a single Ozempic dose is far below any threshold that would cause concern, even for patients with propylene glycol sensitivity.

Phenol is an antimicrobial preservative. Because Ozempic pens are multi-dose (used over four weeks), they need a preservative to prevent bacterial growth between injections. Phenol at this low concentration is well-tolerated for most patients but can cause local injection site irritation in a small subset.

Water for injection is sterile, pyrogen-free water that meets the United States Pharmacopeia (USP) standard. It's the solvent that holds everything else.

Hydrochloric acid and sodium hydroxide are added in trace amounts to fine-tune the final pH to 7.4. The amounts are too small to cause any clinical effect.

How semaglutide is manufactured

Semaglutide is not extracted from any animal or plant. It's manufactured through recombinant DNA technology, a process Novo Nordisk has refined over decades of insulin and peptide manufacturing.

The simplified process:

1. Gene insertion. Scientists insert a DNA sequence coding for the precursor peptide into Saccharomyces cerevisiae, a strain of baker's yeast. The yeast becomes a tiny factory that produces the precursor peptide.
2. Fermentation. The engineered yeast is grown in large stainless steel fermentation tanks (sometimes 100,000 liters or more) under tightly controlled temperature, pH, and nutrient conditions.
3. Harvesting. The yeast cells are separated from the broth and broken open. The precursor peptide is purified through a series of chromatography steps that remove yeast proteins and impurities.
4. Chemical modification. The 18-carbon fatty diacid chain is attached to the precursor peptide using solid-phase peptide synthesis (SPPS) chemistry. This step converts the precursor into final semaglutide.
5. Purification. The modified peptide goes through additional chromatography to remove unmodified precursor, side products, and any chemical residues.
6. Formulation. Purified semaglutide is dissolved in the buffer system (water, phosphate buffer, propylene glycol, phenol) at the target concentration.
7. Filling and pen assembly. The solution is sterile-filtered, filled into 1.5 mL or 3 mL cartridges, and assembled into the prefilled pen device.

Every batch goes through dozens of in-process and final-release tests before it's allowed to ship. The U.S. Food and Drug Administration (FDA) inspects Novo Nordisk manufacturing facilities and audits batch records. Each lot has a certificate of analysis showing it meets specifications for purity, potency, sterility, and pH.

What Ozempic does NOT contain

A list of ingredients people sometimes ask about, with the answer:

• Insulin. No. Ozempic is not insulin and doesn't contain insulin. The two are different drug classes.
• Animal products. No. Semaglutide is made in yeast, not derived from any animal. Ozempic is not vegan-certified, but it doesn't contain animal-derived ingredients.
• Pork or beef byproducts. No.
• Gluten. No.
• Lactose or dairy. No.
• Soy. No.
• Latex. The pen needle is latex-free per Novo Nordisk's product specifications.
• Alcohol (ethanol). No. The propylene glycol is sometimes confused with ethanol but is a different compound.
• Sugar or sweeteners. No.
• Artificial colors or flavors. No. The solution is clear and colorless.

For patients with religious dietary restrictions, the kosher and halal status of Ozempic depends on whether the certifying body considers yeast fermentation acceptable. Most kosher authorities consider Ozempic acceptable; halal status varies by certifying authority.

How the pen is engineered

The Ozempic pen itself is a precision medical device, not just a tube with liquid. Each pen has:

• A cartridge holding 1.5 mL or 3 mL of the semaglutide solution
• A precision dose-counter mechanism that limits each injection to the prescribed dose
• A spring-loaded plunger that delivers the dose at a controlled rate
• A click counter (you hear and feel a click for each dose unit dialed)
• A standard pen needle thread that accepts compatible NovoFine or BD needles

The dose-counter is what prevents overdose. You can only dial up to the maximum the pen allows for that strength. The 0.25/0.5 mg starter pen, for example, won't dial higher than 0.5 mg even if you try.

A single 1.5 mL pen contains four weekly doses at the 0.25 mg or 0.5 mg level, two doses at 1 mg, or one dose at 2 mg, depending on the strength.

For a deeper look at how to read the pen, see our guide on reading the Ozempic click chart and our article on how many clicks make 8 mg.

Ozempic vs Wegovy vs Rybelsus: same molecule, different formulations

Semaglutide appears in three different products from Novo Nordisk:

The active ingredient is identical: semaglutide. What differs is the dose, the delivery route, and the FDA-approved indication.

Wegovy is dosed slightly higher because the weight management trials (STEP 1, Wilding et al., NEJM 2021) used the 2.4 mg dose. Rybelsus is an oral tablet that uses an absorption enhancer called SNAC (sodium N-(8-(2-hydroxybenzoyl) amino) caprylate) to help the peptide survive the stomach. The SNAC isn't in Ozempic because injection bypasses the stomach entirely.

You can't substitute one for another. Ozempic for weight loss is technically off-label even though the active drug is the same as Wegovy.

Allergy and sensitivity considerations

True allergic reactions to semaglutide are rare but real. The most commonly reported reactions in the SUSTAIN clinical trial program (Marso et al., NEJM 2016) were injection site reactions, which usually involve mild redness or itching near the injection point, not a systemic allergic response.

Patients with a documented allergy to:

• Phenol can react to local injection site irritation. Talk with your provider; alternative medications without phenol exist.
• Propylene glycol (rare) might react. Again, alternatives exist.
• Yeast or yeast proteins are not at risk because the manufacturing process removes essentially all yeast residues. Trace amounts that survive the purification process are well below the threshold for allergic reaction.

Severe allergic reactions (anaphylaxis, angioedema) have been reported in post-marketing surveillance but are rare. Anyone with a history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 (MEN 2) should not use semaglutide based on the FDA boxed warning.

If you experience facial swelling, throat tightness, difficulty breathing, or hives after an injection, seek emergency care.

FAQ

What is the active ingredient in Ozempic? Semaglutide. It's a 31-amino-acid peptide engineered to mimic the natural human hormone GLP-1, with modifications that extend its half-life to about seven days. Each pen contains 1.34 mg of semaglutide per mL of solution.

Is Ozempic made from animals or animal products? No. Semaglutide is manufactured in yeast cells (Saccharomyces cerevisiae) using recombinant DNA technology. No animal-derived ingredients are used in production. The pen materials themselves are also free of animal byproducts.

What are the inactive ingredients in Ozempic? Disodium phosphate dihydrate (buffer), propylene glycol (tonicity agent), phenol (preservative), water for injection (solvent), and trace amounts of hydrochloric acid and sodium hydroxide for pH adjustment. There are no colorings, flavors, or excipients beyond these.

Does Ozempic contain insulin? No. Ozempic is a GLP-1 receptor agonist, not an insulin. It works by mimicking the action of the GLP-1 hormone, which prompts the pancreas to release its own insulin in response to elevated blood sugar. Ozempic itself contains no insulin.

Is Ozempic gluten-free, dairy-free, and soy-free? Yes to all three. Semaglutide is a peptide produced in yeast and contains no gluten, dairy, soy, or any common food allergens. The inactive ingredients also contain none of these.

Why does Ozempic need a preservative? The Ozempic pen is multi-dose, meaning the same cartridge is used for up to four weekly injections. The phenol preservative prevents bacterial contamination between uses. Single-dose vials (which compounded semaglutide sometimes uses) don't need preservatives if used immediately.

Is the semaglutide in compounded versions the same as the semaglutide in Ozempic? Compounded semaglutide is the same molecular structure but is prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded products are not FDA-approved, are not interchangeable with Ozempic, and may have different inactive ingredients.

How long does Ozempic stay in your body? Semaglutide has a half-life of about seven days, which is why it's dosed once weekly. After stopping treatment, semaglutide is essentially cleared from the body within five to seven weeks (about five half-lives).

Does Ozempic contain alcohol? No. Some people see "propylene glycol" on the ingredient list and assume it's alcohol. Propylene glycol is not ethanol and is not metabolized as alcohol. It's a common pharmaceutical excipient with no intoxicating effect.

Can I take Ozempic if I'm allergic to penicillin or other antibiotics? Yes. Semaglutide and antibiotics are unrelated drug classes. A penicillin allergy doesn't predict a semaglutide allergy. Tell your provider about all your allergies anyway, and watch for any reaction to your first few doses.

Is the Ozempic pen made of latex? The current Novo Nordisk Ozempic pen is latex-free per the manufacturer's product specifications. Patients with latex allergies can use Ozempic without concern, though it's worth confirming with the package insert in case future product changes occur.

How is Ozempic stored before it reaches the pharmacy? Ozempic is shipped and stored under refrigeration at 36 to 46 degrees Fahrenheit (2 to 8 Celsius). Pharmacies maintain cold-chain protocols. Once you receive your pen, you can keep it at room temperature (up to 86 Fahrenheit, 30 Celsius) for up to 56 days during use.

Sources

1. Lau J, et al. Discovery of the once-weekly glucagon-like peptide-1 (GLP-1) analogue semaglutide. Journal of Medicinal Chemistry. 2015;58:7370-7380.
2. Marso SP, et al. Semaglutide and cardiovascular outcomes in patients with type 2 diabetes (SUSTAIN-6). New England Journal of Medicine. 2016;375:1834-1844.
3. Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). New England Journal of Medicine. 2021;384:989-1002.
4. Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). New England Journal of Medicine. 2022;387:205-216.
5. Novo Nordisk. Ozempic (semaglutide) injection prescribing information. Revised 2024.
6. United States Pharmacopeia. USP Monograph: Water for Injection. USP-NF, 2024 edition.
7. United States Food and Drug Administration. Drug Approval Package: Ozempic (semaglutide) injection. NDA 209637.
8. Knudsen LB, Lau J. The discovery and development of liraglutide and semaglutide. Frontiers in Endocrinology. 2019;10:155.
9. Davies M, et al. Pharmacokinetics, pharmacodynamics, and clinical efficacy of semaglutide. Diabetes, Obesity and Metabolism. 2018;20(Suppl 1):24-39.

Footer disclaimers

Platform Disclaimer. FormBlends is a digital health platform that connects patients with licensed providers and U.S.-based pharmacies. We do not manufacture, prescribe, or dispense medication directly. All clinical decisions are made by independent licensed providers.

Compounded Medication Notice. Compounded semaglutide and tirzepatide are not FDA-approved. They are prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded medications have not undergone the same review process as FDA-approved drugs and are not interchangeable with brand-name products.

Results Disclaimer. Individual results vary. Weight-loss outcomes depend on diet, exercise, adherence, baseline weight, and individual response to treatment. Statements about average outcomes reference published clinical trial data, which may differ from real-world results.

Trademark Notice. Ozempic, Wegovy, and Rybelsus are registered trademarks of Novo Nordisk A/S. NovoFine is a trademark of Novo Nordisk. BD is a trademark of Becton, Dickinson and Company. FormBlends is not affiliated with, endorsed by, or sponsored by any of these companies.