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The needle is 4 mm long and thinner than a flu-shot needle, and it goes into fat rather than muscle. Most people feel nothing. The fear is the barrier — not the needle.
The injection is subcutaneous — into fat, not muscle. That is why these three sites and no others: they are the ones with a fat layer you can rely on.
Stay at least two inches away from the navel. This is the site most people default to: the fat layer is generous, it is easy to see what you are doing, and it is the least awkward to reach one-handed.
The upper, outer part of the thigh. Easy to reach sitting down. Some people find it stings slightly more than the abdomen, which is usually a sign of injecting somewhere with less fat under the skin.
The fleshy part at the back of the arm. Genuinely awkward to do to yourself — this is the site to hand to someone else if you have that option.
Never inject into skin that is tender, bruised, red, hardened or damaged — and rotate weekly, moving at least an inch from the last spot. Repeatedly hitting the same patch can turn the fat underneath lumpy or hollow (lipodystrophy), and absorption from a damaged site becomes unpredictable, which means your dose becomes unpredictable.
You press the pen flat against the skin at 90 degrees and push. It clicks. Relief — done. Except that first click means the injection has started, not finished. Pull away now and part of your dose ends up on your stomach instead of in it. Hold the pen where it is for five to ten seconds, until a second click and the dose window reading zero. Only then take it off.
One more thing worth doing: take the pen out of the fridge about half an hour before. A cold injection stings noticeably more than a room-temperature one, and that sting is what most people remember and dread next week.
| Drug | Form | Weight loss (trial) |
|---|---|---|
| Zepbound | Shot | ~21% at 72 weeksSURMOUNT-1 |
| Wegovy (injection) | Shot | ~15% at 68 weeksSTEP 1 |
| Wegovy pill | Pill | 13.6% at 64 weeksOASIS 4 |
| Foundayo (orforglipron) | Pill | 12.4% at 72 weeksATTAIN-1 |
Roughly a point and a half over the same molecule swallowed, and about eight points over the best pill there is. Whether four seconds a week is worth eight percentage points of your body weight is a real question — but it should be asked with those numbers in front of you, not with a vague dread of needles standing in for them.
Far less than people expect, and the fear is doing more work than the needle is. The Zepbound pen carries a 32-gauge, 4 mm needle — thinner and shorter than the one used for a flu shot or a blood draw, and it is going into the layer of fat just under the skin rather than into muscle. Most people report feeling a pinch at worst, and many report feeling nothing at all. A cold pen stings more than a room-temperature one, so taking it out of the fridge for about half an hour beforehand is worth doing. If a particular spot genuinely hurts, that usually means you found somewhere with too little fat under the skin — move, do not push.
Three approved places: the abdomen (staying at least two inches clear of the navel), the front or outer thigh, and the back of the upper arm. The injection goes subcutaneously — into fat, not muscle — which is why those three sites are the ones with a reliable fat layer. Never inject into skin that is tender, bruised, red, hardened or damaged.
Yes, and it is not optional busywork. Rotate weekly and move at least an inch from your last spot. Injecting into the same patch repeatedly can cause lipodystrophy — the fat under the skin changes texture, going lumpy or hollow — and drug absorption from a damaged site becomes unpredictable. A simple clockwise pattern around the abdomen, moving on to thigh and arm, is enough. Write it down if you will not remember, because you will not remember.
On the Wegovy pen you press the shield flat against the skin at 90 degrees and push firmly. The first click means the injection has started — that is not the moment to pull away, which is the most common beginner mistake. Hold it in place for five to ten seconds until you hear a second click and the dose window reads zero. Then remove it. Pulling out at the first click means part of your dose ends up on your skin rather than in you.
On the numbers, yes, and it is not particularly close. Injected Wegovy reaches about 15% average weight loss at 68 weeks (STEP 1) and Zepbound about 21% at 72 weeks (SURMOUNT-1). The best pill — the Wegovy pill, oral semaglutide 25 mg — reaches 13.6% at 64 weeks (OASIS 4). So a pill costs you roughly a point and a half against the same molecule injected, and around eight points against the strongest injection there is. The pill also demands a daily empty stomach and a 30-minute wait; the shot is once a week and you can eat whatever you like. What the pill buys you is the absence of a needle — and if that is genuinely what stands between you and starting treatment at all, it is worth every one of those eight points.
Injection technique here follows the manufacturers’ own instructions for use. Your pen comes with them in the box — read them, because pen mechanics differ between products. This page is orientation, not a substitute for the leaflet or your prescriber.