Once a clinician has prescribed semaglutide, the mechanics of actually giving yourself the shot are simpler than most people fear — but the details matter, and they come straight from the FDA prescribing information for each product. This guide walks through where to inject, how to handle the pen, timing, missed doses, storage, and disposal. One rule sits above all of it: the instructions that ship with your pen, and what your prescriber tells you, always win over any general article, including this one. Ozempic and Wegovy pens are not identical, so read the leaflet in your box.[1][2]
Where to inject: abdomen, thigh, or upper arm
Semaglutide is a subcutaneous injection — it goes into the fatty tissue just under the skin, not into muscle or a vein. The label for both Ozempic and Wegovy names three approved sites: the abdomen, the thigh, or the upper arm.[1][2] All three work; pick whichever you can reach comfortably and pinch a little tissue on. If you use the abdomen, stay a couple of inches away from the navel.
The one non-negotiable is rotation. The prescribing information explicitly instructs you to change (rotate) the injection site with each dose and not to use the same spot every time.[1][2] Rotating spreads out the minor tissue stress of repeated injections and helps avoid lumps or irritation building up in one area. You can move between sites week to week, or shift within a region — the point is simply not to hit the identical spot each time.
Know your pen: Ozempic vs Wegovy
This is where the two products diverge, and where generic advice gets people into trouble. They are the same molecule but delivered by different devices.
Ozempic comes as a multi-dose, single-patient dial pen. One pen holds several weekly doses; you dial the prescribed dose, attach a fresh needle each time, inject, and keep the pen for your next dose.[1] Because you reuse it across weeks, storage-after-first-use and needle changes matter (more below).
Wegovy is dispensed in more than one presentation. Novo Nordisk instructs clinicians to tell each patient which Wegovy device they are getting — a single-dose pen or syringe, or the reusable FlexTouch single-patient-use pen — and to make sure they are trained for that specific device.[2] With the single-dose presentations, each pen or syringe delivers one shot and is discarded after use; there is no dialing and no reusing.[2] So “how do I use my Wegovy pen” genuinely depends on which pen you have. Check the box.
Step by step: attach, prime, inject
The exact steps are in your product’s Instructions for Use, and you should follow those. In broad strokes, the routine looks like this:
1. Inspect the medicine. The label tells you to look at the liquid before use: it should appear clear and colorless, and you should not use it if it is cloudy, colored, or has particles in it.[1] Do not use it if it has been frozen.[1][2]
2. Attach a new needle. For a pen that takes separate needles (Ozempic, and the Wegovy FlexTouch), wipe the pen’s rubber seal, then attach a new, sterile needle each time. Never reuse a needle and never leave one attached between doses.
3. Prime / check the flow when your device calls for it. Some pens require a flow check before the first use of a new pen to confirm medicine appears at the needle tip and to clear air. Whether and when to prime depends on the device, so follow the Instructions for Use for your specific pen rather than assuming.
4. Dial the dose (dial pens only). On the Ozempic pen you set the prescribed dose on the counter.[1] Single-dose Wegovy pens and syringes have no dose to dial — the dose is fixed.[2]
5. Inject subcutaneously. Pinch or spread the skin at a rotated site (abdomen, thigh, or upper arm), insert the needle, and deliver the dose, holding as your device instructs so the full dose goes in.[1][2]
6. Dispose of the needle safely (see below), and store the pen correctly if it is a reusable one.
Never share your pen with anyone else, even with a fresh needle — the label warns that sharing can pass on infection.[1] If any of this is unfamiliar, ask your pharmacist or prescriber to watch your first injection; that is a normal, expected request.
Timing: once weekly, same day, food optional
Semaglutide is a once-weekly injection. Both labels say to give it on the same day each week, at any time of day, and with or without meals.[1][2] You do not need to inject before breakfast or on an empty stomach; morning or night is fine as long as it is consistent enough that you remember it. The Wegovy label notes that the day of the week and the injection site can be changed if needed without any dose adjustment, as long as your last dose was at least a couple of days earlier.[2]
Also worth separating out: the once-weekly injectable semaglutide covered here is not the same as oral semaglutide tablets, which have their own empty-stomach timing rules. If tablets are what you were prescribed, see our note on Rybelsus versus Ozempic.
What to do about a missed dose
The missed-dose rules are different for the two products, which is exactly why you cannot generalize:
Ozempic: if you miss a dose, administer it within 5 days of the missed dose; if more than 5 days have passed, skip it and resume on your regular schedule.[1]
Wegovy injection: if a dose is missed and the next scheduled dose is more than 2 days (48 hours) away, take it as soon as possible; if the next dose is less than 2 days away, skip the missed dose and resume on your regular day.[2]
When in doubt, do not double up to “catch up,” and check your own product leaflet or ask your pharmacist.
Storage: how to store Ozempic and Wegovy
Before first use, both products are refrigerated: store the pen in a refrigerator at 2°C to 8°C (36°F to 46°F). Do not store it in the freezer or right against the fridge’s cooling element, and do not freeze it — if it has been frozen, do not use it.[1][2] Keep it in its original carton to protect it from light until you use it.[1][2]
Ozempic after first use: once you have started a pen, it can be kept for 56 days either at controlled room temperature, 15°C to 30°C (59°F to 86°F), or in the refrigerator. Keep the pen cap on when it is not in use, and still keep it away from freezing.[1] That 56-day window is why it helps to note the date you first used the pen.
Wegovy: the single-dose pen or syringe is used once and then discarded, so there is no “after first use” reuse period for those presentations — you are not storing a partly used device.[2] If you were given the reusable FlexTouch pen instead, follow the specific storage instructions for that device in your leaflet. Either way, never freeze Wegovy.[2]
Injection-site reactions and other local effects
Mild reactions at the injection site — redness, itching, a small bump, or tenderness — can happen and are generally minor and short-lived; rotating sites as instructed helps. The far more common and more relevant side effects of semaglutide are gastrointestinal (nausea, and other GI effects that rise during dose escalation), not skin reactions. We map how those come and go in the GLP-1 GI side-effect timeline. As with any injectable, a reaction that is severe, spreading, or looks like a whole-body allergic response (swelling of the face or throat, trouble breathing) is a reason to seek urgent care rather than to keep dosing.
Sharps disposal
Used pen needles are sharps and should not go in your household trash or recycling. Put each used needle straight into an FDA-cleared sharps disposal container — or, if you do not have one, a heavy-duty puncture-resistant plastic container with a tight lid — and follow your community’s guidelines for disposing of the full container. Never recap a needle by hand to save it, and never reuse or share needles. Because the medication itself was validated in trials at these once-weekly doses, using the device as directed — one new needle, one dose, safe disposal — is part of getting the result the trials showed.[3]
If you are still deciding between products or working out how to obtain a prescription, our practical guides on how to get Ozempic and how to get Wegovy, plus the Ozempic versus Wegovy evidence breakdown, cover the decisions that come before the first injection.
This article is educational and not medical advice. Ozempic and Wegovy are prescription medications; injection technique, dosing, storage, and what to do about a missed dose should follow the Instructions for Use in your specific product and the guidance of your prescriber or pharmacist. Where products differ, this guide defers to each drug’s FDA prescribing information.