A 0.5 mg dose of Ozempic (semaglutide) stays in your system for approximately 5 weeks after your last injection. The drug has an elimination half-life of about 1 week, meaning your body clears half the remaining drug every 7 days. After 5 half-lives, the amount left is negligible.
How the 5-Week Timeline Works
Semaglutide’s half-life is roughly 160 hours, or about 7 days. That means one week after your last 0.5 mg injection, about 0.25 mg worth of drug activity remains. After two weeks, roughly 0.125 mg. Each week cuts the remaining amount in half again. By the fifth week, the circulating levels are so small they’re essentially zero.
This timeline is the same regardless of whether you’re on the 0.25 mg, 0.5 mg, 1 mg, or 2 mg dose. The half-life doesn’t change with dose size. What changes is the starting amount, but five weeks is enough time for any dose to clear. The body eliminates semaglutide primarily through urine and feces, though only about 3% leaves as intact drug. Most of it gets broken down before excretion.
Steady State and What It Means for You
If you’ve been taking Ozempic weekly for a while, there’s an important detail: the drug accumulates. When you inject once a week, each new dose arrives before the previous one has fully cleared. After 4 to 5 weeks of consistent weekly dosing, you reach what’s called steady state, where the amount building up equals the amount being cleared. At steady state on 0.5 mg, you have more total semaglutide in your body than a single 0.5 mg injection would produce.
This means the 5-week clearance window starts from your last injection, not from when you first notice effects wearing off. If you’ve been on Ozempic for months, you’ll have a higher baseline level to clear compared to someone who only took one or two doses. In practice, though, the timeline remains about 5 weeks because the half-life governs how quickly each “layer” of accumulated drug is removed.
When Effects Actually Fade
The drug being detectable in your bloodstream and the drug actively affecting your body are two different things. Most people notice the appetite-suppressing and blood sugar effects start weakening well before the full 5-week clearance period ends. As levels drop below therapeutic thresholds in the first couple of weeks, the functional impact diminishes even though traces remain.
Hunger cues tend to return relatively quickly after stopping. Many people report increased appetite within the first week or two, and weight regain can follow soon after. This is because the drug’s effect on appetite signaling in the brain fades as blood levels drop, even while some semaglutide is still circulating at lower concentrations.
How Long Side Effects Last After Stopping
If you’re asking about clearance time because you’re dealing with side effects, the news is better. Gastrointestinal symptoms like nausea, vomiting, and stomach discomfort typically lessen or disappear within one week to one month after your last injection. Because the drug clears gradually rather than all at once, side effects tend to taper rather than vanish overnight. Most people feel noticeably better by the second or third week.
The 0.5 mg dose sits in the lower-to-middle range of Ozempic dosing, so side effects at this level are generally milder than what people experience at 1 mg or 2 mg. That also means they tend to resolve on the faster end of that one-week-to-one-month window.
Why This Matters for Timing
People search for clearance times for different reasons: switching medications, planning a surgery, trying to conceive, or simply wanting to know when the drug will be fully out. Here’s what the 5-week window means in practical terms:
- Switching medications: Your doctor may overlap or space out the transition depending on the new drug. The lingering semaglutide won’t cause dangerous interactions with most medications, but the timing matters for dosing the replacement correctly.
- Pregnancy planning: The FDA labeling recommends stopping Ozempic at least 2 months before a planned pregnancy, which provides a comfortable margin beyond the 5-week clearance period.
- Pre-surgical fasting: Some anesthesiologists want patients off GLP-1 drugs before procedures because of the slowed stomach emptying these drugs cause. Even after you stop injecting, that effect can linger for several weeks while the drug clears.
The bottom line: after your last 0.5 mg injection, expect the drug to be functionally gone within 3 to 4 weeks and fully cleared by 5 weeks. Your appetite and blood sugar patterns will shift back toward their pre-treatment baseline during that window.