How long does Semaglutide stay in your system?
Semaglutide has a published half-life of approximately 1 week. By the standard pharmacology rule of thumb, a drug is about 97% eliminated after roughly five half-lives, which here works out to about 35 days (5 weeks). That matches the Ozempic label itself, which states that semaglutide remains in circulation for about 5 weeks after the last dose.
Source: Ozempic label, DailyMed · FDA label · measured: subcutaneous · dataset reviewed September 23, 2026
What is the half-life of Semaglutide?
The Ozempic prescribing information gives semaglutide an elimination half-life of approximately 1 week after subcutaneous injection. That is extraordinarily long for a peptide. Native GLP-1, the gut hormone semaglutide is modelled on, is rapidly broken down by the enzyme DPP-4 and does not last long in the blood at all.
Semaglutide gets its week from two changes to that template. Amino acid substitutions make it resistant to DPP-4, and a fatty-acid side chain lets it bind reversibly to albumin, the most abundant protein in blood. The bound fraction is shielded from enzymes and from clearance by the kidney, and it is released back into circulation slowly. Albumin binding is the reason the number is counted in days rather than minutes.
How much Semaglutide is left after each half-life?
Each half-life removes half of whatever is left, so the percentages are pure arithmetic and the same for any compound; only the clock changes. For Semaglutide, one half-life is 7 days. The rows below run that forward for a single amount with nothing added.
| Half-lives elapsed | Time elapsed | Remaining | Cleared |
|---|---|---|---|
| 1 | 7 days | 50% | 50% |
| 2 | 14 days (2 weeks) | 25% | 75% |
| 3 | 21 days (3 weeks) | 12.5% | 87.5% |
| 4 | 28 days (4 weeks) | 6.25% | 93.75% |
| 5 | 35 days (5 weeks) | 3.13% | 96.88% |
| 6 | 42 days (6 weeks) | 1.56% | 98.44% |
| 7 | 49 days (7 weeks) | 0.78% | 99.22% |
Why do the numbers differ between sources?
For semaglutide the sources largely agree, which is unusual. The label says approximately 1 week. An independent phase 1b trial, the one that also characterised cagrilintide, measured semaglutide at 145 to 165 hours, which is roughly six to seven days.
When a different figure turns up, check what it is describing. The time to peak concentration after an injection, the half-life, and the label's statement about how long the drug stays in circulation are three different quantities. The 5 week figure on the label is the practical consequence of a 1 week half-life, not a competing value.
What does a half-life not tell you?
It does not tell you how long the effects last. Appetite, gastric emptying and blood glucose respond to semaglutide through receptors in the pancreas, gut and brain, and those responses do not switch off on the same curve that plasma concentration follows.
It also does not describe what happens to weight after treatment ends. That is an outcome question answered by trials, not by pharmacokinetics, and the STEP 1 extension recorded significant weight regain after stopping. Because semaglutide is normally used repeatedly, levels also build toward a plateau that a single decay curve does not show.
Can you run the numbers yourself?
The estimator applies the same decay arithmetic to any half-life, starting amount and time you enter. It opens with Semaglutide's published value loaded. Type another figure to see how sensitive the result is to it.
Published value: Approximately 1 week (Subcutaneous) · Ozempic label, DailyMed · Compound profile
Show the math
What are the limits of this estimate?
Everything above is a single-compartment approximation: one pool of drug, falling by the same fraction in every interval. Real elimination varies with kidney and liver function, body composition, formulation and route, and a published figure describes only the route and the people it was measured in. Many compounds also show a fast distribution phase before the slower elimination the table describes.
A half-life is not a dosing schedule. Labelled intervals come from clinical trials that measured outcomes and tolerability, and nothing on this page suggests when to take, repeat or stop anything. Whether Semaglutide is out of your system for drug-testing purposes is a different question again. Tests often look for metabolites rather than the parent compound, and the answer depends on the assay, its sensitivity and the sample type, none of which a plasma half-life captures.
FAQ.
Why does semaglutide stay in the body so much longer than natural GLP-1?
Because it was engineered to. Natural GLP-1 is rapidly degraded by the enzyme DPP-4. Semaglutide carries amino acid substitutions that resist DPP-4 and a fatty-acid side chain that binds albumin in the blood, so the bound fraction acts as a slowly released reservoir. The result is a half-life of approximately 1 week on the Ozempic label.
Is the 5 week figure the same as the half-life?
No. The half-life is the time for the concentration to fall by half, approximately 1 week. The label's statement that semaglutide remains in circulation for about 5 weeks after the last dose describes several half-lives in a row, which is the same arithmetic as the five half-life rule of thumb.
Does oral semaglutide have a different half-life?
This page uses the subcutaneous figure from the Ozempic label, because that is the value in our sourced dataset. We have not added a separate figure for the oral tablet, so we do not quote one. The route changes how a drug enters the blood, which is why every value on this site carries the route it was measured on.
For what the evidence on Semaglutide actually shows, read the Semaglutide profile. For approval and regulatory position, see is Semaglutide legal. The half-life reference lists every sourced value side by side, including the compounds where a number circulates online with no reliable human data behind it.