GLP injections help you experience less food cravings by controlling insulin and glucose levels, by calming down the digestive process, and by helping you sleep better. There are however possible side effects such as nausea, diarrhea and stomach pains.
Russell Sammut
GLP-1 injections reduce food cravings, and nausea, diarrhoea and stomach pain are among their most common side effects. Each of the three explanations given has published support: steadier blood sugar, slower digestion, and better sleep, which trials have linked to fewer cravings.How we reached this verdict ↓
Analysis and evaluation
GLP-1 injections such as semaglutide and tirzepatide copy gut hormones released after eating. Trials show they cut cravings, and each of the routes the speaker named has published support.
Fewer cravings
In a 20-week double-blind trial of 72 adults with obesity, people on weekly semaglutide reported fewer and weaker food cravings, less hunger and better control of eating than those on a placebo. They also ate 35% less at a buffet lunch. A two-year trial, STEP 5, found the reduction in cravings still there after 104 weeks, and a six-week trial of tirzepatide found similar effects.
How the drugs reduce cravings
The brain. A 2025 review in the American Journal of Medicine describes the drugs acting on the brain regions that control appetite, suppressing hunger and strengthening the feeling of fullness.
Insulin and glucose. The drugs raise insulin when blood sugar is high and hold back glucagon, which lowers blood sugar. The same review lists steadier blood sugar as one of the ways they reduce hunger.
Digestion. The drugs slow the rate at which the stomach empties, which prolongs the feeling of fullness. The effect may fade with time: the 20-week semaglutide trial found no evidence of slower stomach emptying by its end, using an indirect measure.
Sleep. Trials suggest that better sleep reduces cravings. In a 2025 trial of 27 adults with overweight or obesity, eight weeks of therapy to improve sleep reduced cravings for sweet and savoury foods compared with no treatment. In a 2022 trial of 80 adults with overweight who slept less than 6.5 hours a night, sleeping about 1.2 hours more cut daily intake by about 270 kcal. Over two weeks, the sleep group's weight ended about 0.9 kg lower than the control group's. Other sleep trials have found smaller or no effects on how much people eat.
The drugs can also improve sleep themselves, at least in people with obesity and obstructive sleep apnoea. In the SURMOUNT-OSA trials, tirzepatide cut breathing interruptions during sleep by about 20 to 24 an hour more than a placebo and improved patients' own ratings of their sleep. We found no trials testing whether the drugs improve sleep in people without sleep apnoea.
Side effects
The side effects named are among the most common. In STEP 1, the main trial of semaglutide 2.4 mg for weight loss, all three were more common on the drug than on a placebo. Nausea, the most frequent, affected 44% of people on semaglutide against 17% on a placebo. Most cases were mild to moderate and passed with time, but 4.5% of people on semaglutide stopped treatment because of digestive side effects.
Evaluation
What was said holds. Reduced cravings are one of the ways the drugs help people lose weight, each route the speaker described has published support, and the side effects he listed are the most common ones.
Editorial note
How we assessed this claim
We checked each part of the claim separately: the effect on cravings, each of the three explanations given, and the side effects. We used placebo-controlled trials where they exist and recent reviews for how the drugs work.
On sleep, we checked whether better sleep reduces cravings rather than whether the drugs improve sleep in general; the speaker was describing his own experience there. Every part of the claim has published support, so it is rated True.
Limitations
- The speaker did not say which GLP-1 drug he used. Most of the evidence cited is for semaglutide; the only tirzepatide trial on cravings lasted six weeks, and the side-effect figures are for semaglutide alone.
- The sleep trials are small and short: 27 people over eight weeks and 80 people over two weeks. In the smaller one, self-reported sleep improved but sleep measured by a wrist device did not change.
- The link between steadier blood sugar and less hunger comes from a review, not from a trial designed to test it.
- The semaglutide trials cited were run or funded by Novo Nordisk, which makes the drug.
Sources
- Friedrichsen M. et al., The effect of semaglutide 2.4 mg once weekly on energy intake, appetite, control of eating, and gastric emptying in adults with obesity, Diabetes, Obesity and Metabolism (2021)
- Wharton S. et al., Two-year effect of semaglutide 2.4 mg on control of eating in adults with overweight/obesity: STEP 5, Obesity (2023)
- Martin C.K. et al., Tirzepatide on ingestive behavior in adults with overweight or obesity: a randomized 6-week phase 1 trial, Nature Medicine (2025)
- Moiz A. et al., Mechanisms of GLP-1 receptor agonist-induced weight loss: a review of central and peripheral pathways in appetite and energy regulation, American Journal of Medicine (2025)
- Merchant A.M. et al., Effect of a cognitive behavioural therapy intervention to improve sleep on food preferences: a randomized controlled trial in adults with overweight and obesity, Appetite (2025)
- Tasali E. et al., Effect of sleep extension on objectively assessed energy intake among adults with overweight in real-life settings: a randomized clinical trial, JAMA Internal Medicine (2022)
- Efficacy of GLP-1 receptor agonists in treating obstructive sleep apnea: a systematic review and meta-analysis, including the SURMOUNT-OSA trials (2026)
- Wilding J.P.H. et al., Once-weekly semaglutide in adults with overweight or obesity (STEP 1), New England Journal of Medicine (2021)