How to Inject Semaglutide: Sites, Timing, and Pen Storage
Semaglutide is injected subcutaneously into the abdomen, thigh, or upper arm, once weekly on the same day each week, and sites are rotated rather than reused. The two injectable brands work differently in a way that is often confused: the Wegovy pen is single-dose — one pen delivers one weekly injection and is then discarded — while the Ozempic pen is multi-dose and, after first use, is kept for 56 days at 59–86°F or refrigerated at 36–46°F before being discarded even if product remains. Neither may be frozen; a frozen pen is thrown away, not thawed.
Where to inject
Semaglutide goes into subcutaneous fat, not muscle. The three labelled sites are the abdomen, the thigh, and the upper arm. All three are acceptable, and there is no requirement to favour one.
Sites are rotated between doses. Repeatedly injecting the same spot risks local tissue changes that can affect both comfort and absorption, and rotating is the simplest way to avoid it.
- Abdomen
- Front of the thigh
- Back of the upper arm
When to inject
Once weekly, on the same day each week. The day is chosen for convenience and then kept — consistency matters more than which day it is, because a weekly drug with a long half-life relies on even spacing.
The injectable forms are not tied to meals the way the oral tablet is — Rybelsus has strict instructions about taking it on an empty stomach, and those do not apply to the pens. Follow the instructions for your own product rather than generalising between them.
Storage — the rules differ by brand
This is where the two injectable brands genuinely diverge, and assuming they behave the same way is the common error. They are not two versions of the same device.
The Wegovy pen is single-dose. One pen holds one weekly injection and is discarded after use, so there is no "after first use" window to track at all. Before use it is stored in the refrigerator, and may be kept between 46°F and 86°F for up to 28 days if needed — in its original carton, to protect it from light.
The Ozempic pen is multi-dose and does have an in-use window. After the first injection it may be kept for 56 days at controlled room temperature (59–86°F) or refrigerated (36–46°F), and is then discarded even if product remains in it.
| Brand | Pen type | How long it is kept | Freezing |
|---|---|---|---|
| Wegovy | Single-dose | Discarded after each weekly injection. Up to 28 days at 46–86°F before use. | Never — discard if frozen |
| Ozempic | Multi-dose | 56 days after first use, at 59–86°F or refrigerated 36–46°F. | Never — discard if frozen |
Missed doses
The two brands give different instructions here, and the difference is large enough that following the wrong one means either taking a dose you should have skipped or skipping one you could have taken.
For Wegovy: if the next scheduled dose is more than 2 days (48 hours) away, take the missed dose as soon as possible. If the next scheduled dose is less than 2 days away, skip it. If two or more consecutive doses are missed, dosing is resumed as scheduled, or treatment is reinitiated following the escalation schedule — restarting at a lower dose reduces the gastrointestinal symptoms that come with reinitiation.
For Ozempic: take the missed dose as soon as possible within 5 days. If more than 5 days have passed, skip it and take the next dose on the regular schedule.
| Brand | If recently missed | If too long has passed |
|---|---|---|
| Wegovy | Next dose >2 days away: take as soon as possible | Next dose <2 days away: skip it |
| Ozempic | Within 5 days: take as soon as possible | More than 5 days: skip, resume on schedule |
On injection discomfort
Subcutaneous injection with a fine pen needle is generally well tolerated, and most people find it far less unpleasant than they expected. That is a description of the typical experience rather than a promise about yours — needle anxiety is real, and a prescriber or pharmacist can walk through the first injection with you.
Frequently asked questions
This describes the labelled handling of manufactured pen devices, and the figures above apply only to those. It does not cover reconstituting semaglutide from powder, drawing from a vial, or compounded product obtained outside the approved supply chain — those involve different equipment and concentrations, the storage and missed-dose rules here do not transfer to them, and the FDA has specifically warned about dosing errors with compounded injectable semaglutide. It is also not injection training: the first injection is worth doing alongside a pharmacist or prescriber. If you need to change your dosing day, ask your prescriber rather than shortening the gap between two doses.
- Wegovy (semaglutide) injection — FDA prescribing information, Novo Nordisk
- Ozempic (semaglutide) injection — FDA prescribing information, Novo Nordisk
- Wegovy pen guide and dosing information — Novo Nordisk
- FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products
- What Is Semaglutide? How It Works, Brands, and Who It Is ForWhat is semaglutide and how does it work?
- Semaglutide Side Effects: What Is Common, What Is SeriousWhat are the side effects of semaglutide?
- Semaglutide for Weight Loss: What to Expect, Month by MonthHow much weight will I lose on semaglutide, and how fast?
Part of the Semaglutide Guide.