A simple injection-site rotation schedule for weekly injections
By the DoseRoutine Editorial Team · · · How we review content
Approved weekly GLP-1 injections go subcutaneously into the abdomen, thigh or upper arm, and absorption is equivalent across those sites. Rotating means moving at least one inch (2.5 cm) from the last injection point and not reusing the exact spot for about a month. A four-week rotation — one region per week, a different quadrant each time — is enough to prevent the tissue changes that make absorption unpredictable.
- Abdomen, thigh and upper arm are all labeled sites with equivalent absorption for weekly GLP-1s.
- Stay at least 2 inches (5 cm) away from the navel and avoid scars, moles and bruises.
- Move at least 1 inch from the previous injection point; avoid reusing a precise spot for ~4 weeks.
- Repeated injection into one spot causes lipohypertrophy — firm lumps where absorption becomes erratic.
- Never inject into an existing lump, even if it is painless.
The four-week rotation
- Week 1 — left abdomen, lower quadrant.
- Week 2 — right abdomen, lower quadrant.
- Week 3 — left thigh (front-outer) or left upper arm.
- Week 4 — right thigh (front-outer) or right upper arm.
- Then repeat, shifting each point an inch from where it was last cycle.
Why rotation matters more than technique
Lipohypertrophy is the accumulation of fibrous, fatty tissue where subcutaneous injections are repeatedly given in the same place. It is well documented in insulin therapy, where injecting into affected tissue produces slower and less predictable absorption. The lumps are often easier to feel than to see, and because they are usually painless people keep using them — the area is slightly less sensitive, which makes it the path of least resistance.
For a weekly drug the cumulative exposure per site is lower than with daily insulin, but a year of injections into the same two inches of abdomen is still 50-odd punctures in one place.
Checking your own sites
Once a month, run your fingertips flat over each area you use and compare left to right. You are feeling for firmness, thickening or a rubbery bump under otherwise normal skin. If you find one, stop injecting that area entirely and let it recover, which can take months. Mention it to your prescriber, because switching away from an affected site can change how much drug you actually absorb.
Practical points that reduce soreness
- Let a refrigerated dose sit out for a few minutes — cold solution stings more.
- Let the alcohol swab dry fully before the needle goes in.
- Inject at 90 degrees with a short needle into pinched, relaxed tissue.
- Do not massage the site afterwards; press gently if it bleeds.
- Avoid a limb you are about to work hard — increased blood flow can speed absorption.
This is a summary of published research for general information. Investigational drugs are not available outside clinical trials, and research chemicals sold online are not the same products. Talk to a clinician who knows your history and labs before changing anything you take.
Frequently asked questions
Where should I inject a weekly GLP-1?
The abdomen (at least two inches from the navel), the front-outer thigh, or the back of the upper arm. All three are labeled sites and absorption is equivalent between them.
How far apart should injection sites be?
At least one inch (2.5 cm) from the previous injection point, and ideally do not reuse an exact spot for about four weeks. Spacing that way gives the tissue time to recover and is the main practical step for preventing lipohypertrophy, the firm lumps that make absorption unpredictable.
Does the injection site change how well it works?
For approved weekly GLP-1s, absorption is comparable across the abdomen, thigh and upper arm, so the site you choose is mostly a comfort decision. What does change absorption is injecting into lipohypertrophic tissue, which slows and scatters uptake and makes your effective weekly dose vary without warning.
What are the lumps under my skin?
Firm lumps under the skin are most likely lipohypertrophy from repeated injections in one small area. Stop using that site, move to fresh tissue and let it recover over weeks to months, and raise it with your prescriber. Absorption from affected tissue is unreliable, so dosing through a lump distorts your response.
Should I inject into muscle instead?
No. Weekly GLP-1 products are formulated and tested for subcutaneous delivery into fat, not muscle. Intramuscular injection speeds and changes the absorption profile, is more painful, and is not supported by the label or the trial data the dosing schedule is based on. Use a short needle and pinched skin.
Where to track this
- the best TRT tracking apps for injections and labs — Injection scheduling, site rotation and bloodwork trends in one record.
- DoseRoutine for TRT schedules and injection sites — Site rotation map, dose history and lab reminders for hormone protocols.
- hormone therapy management apps for men — Protocol tracking built around labs, dose changes and symptom notes.
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About the author
DoseRoutine Editorial Team — Maintainers of the DoseRoutine compound library and interaction rule set
The DoseRoutine Editorial Team maintains the compound library and the interaction rule set behind DoseRoutine.
We summarize published trials, regulatory documents (FDA, EMA) and company announcements into plain-English updates. Every factual claim on a post is tied to a linked source below.
Posts are written and reviewed by the editorial team, not by a licensed clinician. This is educational reference content — it never recommends an amount for you to take.
Sources & references
3 sources — primary literature, regulatory documents and company announcements, each linked to the original document. Last reviewed . How we select and review sources.
- RegulatoryDailyMed. Prescribing information labels for semaglutide injection products (Wegovy, Ozempic). View source on dailymed.nlm.nih.gov
- ReferenceCenters for Disease Control and Prevention. Injection safety: one and only campaign guidance for single-dose and multi-dose vials. View source on cdc.gov
- Peer-reviewedWilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384(11):989–1002. View source on pubmed.ncbi.nlm.nih.gov