Semaglutida
GLP-1 receptor agonist used in the treatment of type 2 diabetes and obesity. It is the active ingredient in Ozempic (injectable for diabetes) and Wegovy (injectable for obesity). One of the most prescribed and studied medications of the past decade.
Last updated:: 06/04/2026
Research Status
ANVISA (Brazil)
Approved
FDA (USA)
Approved
EMA (Europe)
Approved
Mechanism of Action
Semaglutide mimics the GLP-1 hormone (glucagon-like peptide-1), which is naturally released by the intestine after meals. It binds to GLP-1 receptors in the pancreas, stimulating insulin release and suppressing glucagon when glucose is elevated. In the brain, it acts on hypothalamic satiety centers, reducing appetite. It also delays gastric emptying, prolonging the feeling of fullness.
Study Protocols
Dosages and regimens used in published clinical studies. This does not constitute a medical prescription.
Obesidade / controle de peso
Subcutânea (SC)Dose de titulação inicial
Dose-alvo do estudo STEP 1
Titulação gradual para minimizar efeitos gastrointestinais. Perda média de 14,9% do peso corporal em 68 semanas.
Diabetes tipo 2
Subcutânea (SC)Redução média de HbA1c de 1,5–1,8%. Benefício cardiovascular demonstrado.
Benefits
Significant weight loss
ProvenSTEP studies demonstrated an average weight loss of 15-17% of body weight over 68 weeks with semaglutide 2.4 mg.
View studyGlycemic control in type 2 diabetes
ProvenAverage HbA1c reduction of 1.5-1.8% in the SUSTAIN studies, superior to other antidiabetic agents.
View studyCardiovascular event reduction
ProvenThe SELECT study showed a 20% reduction in major adverse cardiovascular events (MACE) in patients with obesity without diabetes.
View studyNeuroprotection / Alzheimer's
Under researchPreclinical studies and the phase 3 EVOKE trial are investigating neuroprotective potential in Alzheimer's. Preliminary results are promising but not conclusive.
Risks and Side Effects
Nausea
Moderate(40-44% of patients)Most common side effect. Generally transient, decreases over time. More intense in the first weeks and during dose increases.
Diarrhea
Low(30% of patients)Second most common gastrointestinal effect. Generally mild to moderate.
Pancreatitis
High(Rare (<1%))Small but serious risk of pancreatic inflammation. Requires immediate medical attention if severe abdominal pain occurs.
Muscle mass loss
Moderate(Common)Some of the weight lost may be lean mass (up to 40% in some studies). Resistance exercise is recommended during treatment.
Internet vs. Science
What people say online compared to the actual scientific evidence.
Lose 20 kg effortlessly
Partially trueWhat they claim
Influencers promote it as a magic solution to lose weight without diet or exercise.
Actual evidence
Studies show an average loss of 15-17% of body weight (e.g., ~15 kg for a 100 kg person), but combined with diet and exercise. Without lifestyle changes, the effect is smaller.
Causes thyroid cancer
InconclusiveWhat they claim
Label warnings and social media posts generate fear about thyroid cancer.
Actual evidence
Thyroid tumors were observed in rodents, but not in humans in clinical studies. The risk in humans has not been confirmed, but it is contraindicated in patients with a history of medullary thyroid carcinoma.
Rebound effect — you regain all the weight
Partially trueWhat they claim
When you stop the medication, you regain all the lost weight.
Actual evidence
The STEP 4 study showed that two-thirds of the weight lost was regained after 1 year off the medication. Long-term maintenance likely requires continuous use or significant lifestyle changes.
| Claim | O que dizem | Evidência real | Verdict |
|---|---|---|---|
| Lose 20 kg effortlessly | Influencers promote it as a magic solution to lose weight without diet or exercise. | Studies show an average loss of 15-17% of body weight (e.g., ~15 kg for a 100 kg person), but combined with diet and exercise. Without lifestyle changes, the effect is smaller. | Partially true |
| Causes thyroid cancer | Label warnings and social media posts generate fear about thyroid cancer. | Thyroid tumors were observed in rodents, but not in humans in clinical studies. The risk in humans has not been confirmed, but it is contraindicated in patients with a history of medullary thyroid carcinoma. | Inconclusive |
| Rebound effect — you regain all the weight | When you stop the medication, you regain all the lost weight. | The STEP 4 study showed that two-thirds of the weight lost was regained after 1 year off the medication. Long-term maintenance likely requires continuous use or significant lifestyle changes. | Partially true |
Studies and References (3)
Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. — New England Journal of Medicine (2023) — n=17604
Em pacientes com obesidade sem diabetes, semaglutida 2.4mg reduziu eventos cardiovasculares maiores em 20% comparado com placebo ao longo de 40 meses.
PubMedWilding JPH, Batterham RL, Calanna S, et al. — New England Journal of Medicine (2021) — n=1961
Semaglutida 2.4mg resultou em perda média de 14.9% do peso corporal vs 2.4% com placebo em 68 semanas. 86.4% dos participantes perderam ≥5% do peso.
PubMedMarso SP, Bain SC, Consoli A, et al. — New England Journal of Medicine (2016) — n=3297
Semaglutida reduziu eventos cardiovasculares maiores em 26% comparado com placebo em pacientes com diabetes tipo 2 e alto risco cardiovascular.
PubMedFrequently Asked Questions
Is semaglutide approved in Brazil?
Yes. ANVISA approved Ozempic (semaglutide 0.25 mg, 0.5 mg, and 1 mg) for type 2 diabetes and Wegovy (semaglutide 2.4 mg) for obesity. A medical prescription is required.
What is the difference between Ozempic and Wegovy?
Both contain semaglutide, but at different doses. Ozempic (up to 1 mg) is indicated for type 2 diabetes. Wegovy (2.4 mg) is indicated specifically for weight management in patients with obesity or overweight with comorbidities.
Is a medical prescription required?
Yes. Since April 2025, ANVISA requires retention of a medical prescription for dispensing semaglutide, liraglutide, tirzepatide, and other GLP-1 agonists.
Important notice
This content is strictly informational and educational, based on published scientific research. It does not constitute medical advice, prescription, or encouragement to use any substance. Always consult a qualified physician before starting any treatment.
How to Obtain
This is an approved medication. A medical prescription is required for purchase.