Stopping Ozempic: 7 things that change and what your blood shows

Stopping Ozempic almost always means hunger returns and part of the weight comes back. In the STEP 1 trial extension, participants regained roughly two thirds of their earlier weight loss within a year. Less widely known is that the blood values that improved during treatment tend to drift back towards their old levels too.

That last part is, we think, the most overlooked piece of this story. Nearly every article about stopping is about the scale. Almost none is about your blood.

Below are seven things that can change after you stop, roughly in the order they tend to happen. Each one notes what blood testing can show, and what it cannot.

1. The drug clears slowly, not abruptly

Semaglutide has a half-life of about one week. The Dutch Farmacotherapeutisch Kompas describes a further period of roughly five weeks before most of it has left your body. Most people notice little difference in the first days after their final injection.

That makes those first weeks misleading. You still feel much the same while the level is already falling.

Tirzepatide, the active substance in Mounjaro, has a half-life of around five days. There too, the level tapers off rather than dropping at once.

2. Hunger comes back

The appetite suppression of a GLP-1 drug ends once the drug has cleared. The satiety signal you grew used to over months falls away. Your body did not learn a new target weight during treatment, so the old sense of hunger returns for most people within a few weeks.

Some people describe that hunger afterwards as stronger than before treatment. Whether it truly is stronger, or mainly feels that way after months of low appetite, has not been well studied.

This one cannot be measured in blood. We list it first among the noticeable changes because it is what almost everyone registers first.

3. Stomach and bowel complaints ease for many people

This is the welcome part of the list. Nausea, constipation and feeling full quickly are among the most reported side effects of GLP-1 drugs, and they relate to delayed gastric emptying. Once the drug has cleared, those complaints often fade as well.

Which complaints are reported most, and which blood values relate to them, is covered in this series overview of Ozempic side effects.

4. Part of the weight returns

This is the best-studied point of the seven. The STEP 1 trial extension followed participants for a year after treatment ended. The semaglutide group regained 11.6 percentage points over that year. A net 5.6 percent weight loss remained compared with the start.

That works out at roughly two thirds of the weight lost.

Tirzepatide shows a comparable pattern. In SURMOUNT-4, people who continued lost a further 5.5 percent between week 36 and week 88. The group that stopped gained 14.0 percent over the same period.

We think these figures are often read the wrong way. They do not say the treatment was pointless. In STEP 1, the semaglutide group still held some weight loss a year after stopping, while the placebo group was back at roughly its starting weight.

5. Blood sugar moves with it, but HbA1c lags

Fasting glucose can read higher within weeks. HbA1c responds far more slowly, because it reflects average blood sugar over roughly eight to twelve weeks. An HbA1c drawn shortly after stopping mainly shows the months before.

Imagine two people having blood drawn in July, both with an HbA1c of 39 mmol/mol. One is still on the drug. The other took their last injection in mid-June.

Same number, but for the second person it mostly describes May and June. That second person may meanwhile see a higher fasting glucose. Two values from the same tube, covering two different periods.

That difference in pace is exactly why a single measurement just after stopping can mislead. Thuisarts explains that HbA1c is meant as a look back over a longer stretch, not as a snapshot.

6. Triglycerides and HDL drift back towards old levels

The STEP 1 extension researchers wrote that the cardiometabolic improvements seen from week 0 to week 68 had reverted towards baseline by week 120 for most variables. Triglycerides and HDL cholesterol are among that group.

We've come to read that as the quietest important line in the study. The scale got all the attention. The same tables showed the blood picture moving the same way.

How strongly this happens varies per person. It is an average from a study group, not a prediction for an individual.

7. Blood pressure often rises again

Blood pressure sits in the same category as the lipid values. The drop seen during treatment relates largely to the weight loss itself. When the weight returns, blood pressure moves back with it for many people.

You measure blood pressure at home or at your GP, not in a tube of blood. We still put it on this list. It comes from the same study data as the values above, and it tends to get skipped when people stop.

What changes when?

The seven points above do not move at the same pace. That is the heart of this article: measuring everything at one moment means reading seven clocks that run at different speeds. The overview below sets them side by side.

When does measuring add anything?

That depends mostly on what you want to know. A value with no earlier comparison point says little about movement, because you see a number and not a direction. Some people therefore choose to record a value while treatment is still running, and look again later.

We often see the opposite in practice. People who arranged their GLP-1 drug through an online clinic have no measurement point at all after stopping, and no doctor following along. That group has nothing to fall back on.

Our GLP-1 baseline panel records glucose, HbA1c and the lipid profile among other values, and the GLP-1 check-in panel repeats them later. What a result means for you stays a conversation with your GP.

Further reading in this series: the Mounjaro timeline from week 1 to week 72 and experiences with weight loss injections.

Considering stopping, or just stopped? Raise it with the doctor who prescribed the drug, and discuss which measurements you want on record. Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

References

• Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, Obesity and Metabolism, 2022. PMID 35441470
• Aronne LJ, et al. Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity: The SURMOUNT-4 randomized clinical trial. JAMA, 2024. PMID 38078870
• Rubino D, et al. Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance in adults with overweight or obesity: The STEP 4 randomized clinical trial. JAMA, 2021. PMID 33755728
• Farmacotherapeutisch Kompas, semaglutide monograph (pharmacokinetics and half-life), accessed 2026.
• Thuisarts, information on HbA1c as a measure of average blood sugar over a longer period, accessed 2026.