Ozempic contains one active ingredient, semaglutide, along with four inactive ingredients: disodium phosphate dihydrate, propylene glycol, phenol, and water for injection. The solution holds 1.34 mg of semaglutide per milliliter, regardless of which pen dose you use. It’s manufactured by Novo Nordisk and comes as a clear, colorless liquid with a pH of approximately 7.4.
The Active Ingredient: Semaglutide
Semaglutide is a lab-made version of a hormone your body naturally produces called GLP-1 (glucagon-like peptide-1). After you eat, your gut releases GLP-1 to signal your pancreas to produce insulin and to tell your brain you’re full. Natural GLP-1 breaks down in your body within minutes. Semaglutide has been structurally modified so it lasts much longer, staying active for about a week. That’s why Ozempic is a once-weekly injection rather than something you’d need to take multiple times a day.
Every Ozempic pen contains the same concentration of semaglutide: 1.34 mg per mL. The difference between the 0.25 mg, 0.5 mg, 1 mg, and 2 mg doses is simply how much liquid the pen delivers with each click. The solution itself is identical across all pen strengths.
Inactive Ingredients and What They Do
The four inactive ingredients in Ozempic each serve a specific purpose in keeping the solution stable, safe, and compatible with your body.
Disodium phosphate dihydrate (1.42 mg per mL) acts as a buffer, keeping the solution’s pH steady at around 7.4. That number matches the natural pH of your blood, which is why the injection doesn’t sting or burn the way an acidic solution would. If the pH drifted too far in either direction, the semaglutide molecule could break down and lose its effectiveness.
Propylene glycol (14.0 mg per mL) works as a stabilizer and solvent. It helps keep the semaglutide evenly dissolved in the liquid so you get a consistent dose every time. Propylene glycol is widely used in injectable medications, foods, and cosmetics, and it’s recognized as safe at these concentrations.
Phenol (5.50 mg per mL) serves as a preservative. Because an Ozempic pen is used multiple times over several weeks, the needle punctures the rubber seal repeatedly, which could introduce bacteria. Phenol prevents microbial growth inside the pen between uses. It’s one of the most common preservatives in multi-dose injectable medications.
Water for injection makes up the bulk of the solution and acts as the carrier that dissolves everything else. This isn’t ordinary water. It’s purified to meet strict pharmaceutical standards, free of bacteria, particles, and dissolved minerals that could cause a reaction.
Small amounts of hydrochloric acid or sodium hydroxide may also be added during manufacturing to fine-tune the pH to that 7.4 target. These aren’t listed as formal inactive ingredients because they’re processing aids rather than fixed components of the formula.
What Ozempic Does Not Contain
Ozempic contains no insulin, despite being injected in a similar way and often prescribed alongside diabetes management plans. It also contains no latex in the pen components, which matters if you have a latex allergy. The formulation is free of sugar, gluten, and common food allergens.
Unlike some other injectable medications, Ozempic does not contain human albumin or any animal-derived ingredients. Semaglutide is produced using a biotechnology process involving yeast cells, then purified before being formulated into the final solution.
How the Solution Stays Stable
Before first use, Ozempic pens should be stored in a refrigerator between 36°F and 46°F (2°C to 8°C). Once you start using a pen, it can be kept at room temperature (up to 86°F / 30°C) or in the refrigerator for up to 56 days. After that window, the preservative and buffering system can no longer guarantee the solution’s stability, and the pen should be discarded even if liquid remains.
The solution should always look clear and colorless. If it appears cloudy, has visible particles, or has changed color, the semaglutide may have degraded. This can happen if the pen was exposed to extreme heat, frozen, or kept well past its use-by window.