Where Do You Put the Needle When Your Stomach Is All Stretch Marks?

The first time, I just hovered

I had the pen in my hand and I could not decide where to put it.

The instructions said abdomen. My abdomen, after two pregnancies, is not a plain surface. It is a map. There are silvery lines fanning out from underneath my navel, a wider band low down on the left where I apparently grew fastest, and a flat pale scar across the bottom from my second delivery.

So: abdomen, fine. Which part of it?

I stood there long enough that the moment started to feel ridiculous, and then I picked somewhere and did it and spent the rest of the day wondering whether I had wasted a dose.

What I eventually found out, which was less than I wanted

I want to be straight about this because it is the whole point.

There is no study on injecting a GLP-1 into a stretch mark. Not a small one, not a bad one. I looked, and then I looked again in case I had missed something obvious. Nobody has measured whether the drug absorbs differently through skin that has striae in it.

Which means every confident answer you find — including the confident ones on Reddit, where I spent an evening — is somebody reasoning it out. Some of that reasoning is good. None of it is data.

What I did find was the label, and the label is more useful than I expected.

Three things the label actually says

The approved sites are the abdomen, the thigh and the upper arm. All three. If your stomach is the part that bothers you, there are two other options and they are not second-best.

Site does not change the dose you get. This is the one that stopped my worrying. Wegovy's pharmacokinetics section says similar drug exposure was achieved whether it was injected in the abdomen, the thigh or the upper arm². Where you put it is not a dosing decision.

Rotate with each dose. Not a suggestion — it is written as an instruction, and I had been ignoring it in favor of the one spot that hurt least.

The anatomy, as far as it goes

Stretch marks are changes in the skin itself. A review of striae describes them as areas of thinned skin with altered connective tissue underneath, and — this surprised me — notes that after decades of study, their exact cause is still not established¹.

But the injection is not aiming at skin. It is subcutaneous, meaning it is aiming at the fat underneath the skin. And the fat underneath a stretch mark is not what the stretch mark is made of.

So the reasoning goes: the tissue that changed is not the tissue receiving the drug. That argues the marks probably do not matter much.

The counter-argument, which I will give because I would want it given to me: striae are thinner skin. Over a thin mark, the needle passes through less before it reaches fat. Nobody has measured whether that matters. It is a fair thing to wonder and it is not a documented problem.

The thing I should have been avoiding instead

This is what I actually got wrong, and it had nothing to do with stretch marks.

My cesarean scar. That is genuinely different — dense, fibrous tissue where the blood supply has been disrupted, which is the one situation with a real argument for unpredictable absorption. I now stay a couple of inches clear of it. I had been treating it as just another part of the map.

And the one spot. I had found a place low on my right side that barely stung, and I had been going back to it every single week for two months, because of course I had. Repeatedly injecting into one small patch is the failure mode that actually shows up in injectable medicine — the tissue thickens and absorption gets less predictable.

That is a much better use of worry than the stretch marks were.

What I do now

I run a loop. Left side of my stomach, right side, left thigh, right thigh, and around again, so nowhere gets used more than about once a month. Stretch marks included — I stopped treating them as no-go areas once I understood that the drug is going underneath them, not into them.

I keep clear of the scar. I do not go back to the comfortable spot.

And I have made a kind of peace with the fact that the honest answer to my original question is "nobody knows, and it probably does not matter." That is not the answer I wanted at eleven at night with a pen in my hand. It is better than the confident wrong one I nearly took from a stranger on the internet.

If your stomach looks like mine, the useful thing to know is that you have two other approved sites and the label says they work the same. You are not required to keep injecting into the part of yourself you find hardest to look at.