We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Prescription medication — not a dietary supplement
Semaglutideis a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Most Semaglutide studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2016–2023 with a typical study size of 1,210 participants.
Based on 11 studies · 2 meta-analyses · 9 RCTs · 30,300 total participants
Confidence
HighBy outcome
Semaglutide has an evidence score of 8.5/10 — very strong evidence based on 11 indexed studies, including 2 meta-analyses. An FDA-approved GLP-1 receptor agonist (Ozempic/Rybelsus for type 2 diabetes, Wegovy for chronic weight management) with genuinely strong, large-RCT evidence for glycemic control and substantial weight loss, plus a cardiovascular-outcomes benefit. Honest appraisal: this is a real prescription medicine with real efficacy AND real risks — a boxed warning for thyroid C-cell tumors, pancreatitis and gallbladder risk, very common GI side effects, and growing concern about grey-market/compounded versions. It is included here for reference only, not as a supplement and not auto-recommended. Representative study: PMID 34047443.
The commonly studied dose of Semaglutide is Prescription-only, clinician-titrated. Subcutaneous (Wegovy weight management: escalate to 2.4 mg once weekly; Ozempic diabetes: 0.5-2.0 mg once weekly). Oral (Rybelsus diabetes: 3-14 mg once daily). DO NOT self-dose.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Tirzepatide
Mostly mechanism / observationalAn FDA-approved prescription medication (Mounjaro for type 2 diabetes, Zepbound for obesity and obstructive sleep apnea), not a dietary supplement. Honest appraisal: in head-to-head phase-3 trials it is the most effective approved weight-loss drug to date — up to ~21% body-weight loss over 72 weeks and superior to semaglutide — but it is a real medicine with real risks: a boxed warning for thyroid C-cell tumors, common GI side effects, and pancreatitis/gallbladder signals. Do not source or use it outside a prescription.
Last reviewed June 2026 · evidence from 11 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Semaglutide (GLP-1 receptor agonist)
An FDA-approved GLP-1 receptor agonist (Ozempic/Rybelsus for type 2 diabetes, Wegovy for chronic weight management) with genuinely strong, large-RCT evidence for glycemic control and substantial weight loss, plus a cardiovascular-outcomes benefit. Honest appraisal: this is a real prescription medicine with real efficacy AND real risks — a boxed warning for thyroid C-cell tumors, pancreatitis and gallbladder risk, very common GI side effects, and growing concern about grey-market/compounded versions. It is included here for reference only, not as a supplement and not auto-recommended.
An FDA-approved drug with one of the strongest evidence bases here: multiple large phase-3 RCTs (STEP, SUSTAIN, SELECT) prove substantial weight loss, glycemic control, and reduced cardiovascular events.
Semaglutide is a long-acting analogue of the gut hormone GLP-1 (glucagon-like peptide-1).
It is a prescription drug, NOT a dietary supplement: branded as Ozempic (subcutaneous, type 2 diabetes), Rybelsus (oral, type 2 diabetes), and Wegovy (subcutaneous, chronic weight management), and approved by the FDA for these indications, with an additional indication to reduce cardiovascular risk in adults with established cardiovascular disease and either type 2 diabetes or overweight/obesity.
Mechanistically it activates the GLP-1 receptor in the pancreas (glucose-dependent insulin secretion, suppressed glucagon), brain (appetite suppression and satiety), and gut (slowed gastric emptying).
The evidence base is one of the strongest of any entry on this site: multiple large phase-3 randomized controlled trials. In type 2 diabetes, SUSTAIN-6 (3,297 patients) showed a 26% relative reduction in major adverse cardiovascular events (HR 0.74) and head-to-head SUSTAIN 7 beat dulaglutide on both HbA1c and weight.
For weight management, STEP 1 (1,961 adults without diabetes) produced a mean −14.9% body-weight change vs −2.4% on placebo at 68 weeks, with over half losing ≥15%; STEP 8 showed it substantially out-loses liraglutide.
SELECT (17,604 patients with cardiovascular disease and overweight/obesity but WITHOUT diabetes) showed a 20% relative reduction in cardiovascular death, MI, or stroke (HR 0.80). Oral semaglutide (PIONEER program) reproduces glycemic benefit and was cardiovascular-non-inferior in PIONEER 6.
The honest counterweight: semaglutide carries a boxed warning for thyroid C-cell tumors (rodent medullary thyroid carcinoma) and is contraindicated with a personal/family history of medullary thyroid carcinoma or MEN2; it carries risks of pancreatitis, gallbladder disease, and ileus; gastrointestinal adverse effects (nausea, vomiting, diarrhea) are very common; weight loss includes loss of lean muscle; and the FDA has warned about dosing errors and impurities in compounded/grey-market semaglutide.
It should be used only under a clinician's care, for a genuine medical indication — not as a cosmetic shortcut.
A long-acting analogue of the incretin hormone GLP-1 that binds and activates the GLP-1 receptor in the pancreas, brain, and gastrointestinal tract — the single upstream target driving all downstream effects.
Stimulates insulin release from pancreatic beta cells in a glucose-dependent manner and suppresses glucagon, lowering blood glucose and HbA1c with low intrinsic hypoglycemia risk.
Acts on central appetite-regulating circuits to increase satiety and reduce food intake, the primary driver of the substantial weight loss seen in the STEP trials.
Delays gastric emptying, blunting post-meal glucose excursions and prolonging fullness — and the mechanism behind much of the nausea and the ileus signal.
How Semaglutide works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
Prescription-only, clinician-titrated. Subcutaneous (Wegovy weight management: escalate to 2.4 mg once weekly; Ozempic diabetes: 0.5-2.0 mg once weekly). Oral (Rybelsus diabetes: 3-14 mg once daily). DO NOT self-dose.
Loading: Dose is escalated gradually (typically starting 0.25 mg/week and stepping up over 16-20 weeks) to limit GI side effects — done under clinician supervision.
Can be taken without food
| Form | Type |
|---|---|
| 💊Subcutaneous once-weekly injection (Ozempic / Wegovy) | Recommended |
| 💊Oral tablet (Rybelsus) | Alternative |
Subcutaneous is the form behind nearly all the landmark evidence. Avoid compounded/grey-market semaglutide — the FDA has warned about dosing errors and impurities in non-pharmacy products.
Minimum: 16 weeks
Optimal: 68 weeks
Cycling: Not required
Note: Subcutaneous: once weekly, any time of day, with or without food. Oral (Rybelsus): once daily on an empty stomach. Dosing is titrated upward by a clinician — never self-escalate.
Dose-response data unavailable. The current published research for Semaglutide does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Large, consistent HbA1c reductions across the SUSTAIN and PIONEER phase-3 programs; superior to dulaglutide head-to-head in SUSTAIN 7.
Mean ~15% body-weight reduction at 2.4 mg over 68 weeks in adults with obesity (STEP 1); over half lose ≥15%. Larger than liraglutide (STEP 8).
20-26% relative reduction in major adverse cardiovascular events in dedicated outcomes trials (SUSTAIN-6 in diabetes; SELECT in obesity without diabetes).
Nausea, vomiting, diarrhea and constipation are the most frequent adverse events — usually mild-to-moderate and transient, but a common reason for discontinuation.
As with most large weight reductions, part of the loss is lean mass — a recognized trade-off that argues for resistance training and adequate protein.
Contraindicated — boxed warning for thyroid C-cell tumors.
Use with caution under specialist guidance; generally avoid with prior pancreatitis.
Contraindicated — discontinue at least 2 months before a planned pregnancy.
Not appropriate — this is a prescription drug with real risks, not a cosmetic shortcut. Use only for a clinician-confirmed indication.
Combining with insulin or sulfonylureas raises hypoglycemia risk; the clinician typically reduces those agents. Semaglutide alone is low-hypoglycemia (glucose-dependent action).
Delayed gastric emptying can change the absorption of co-administered oral drugs; clinician monitoring advised, especially for narrow-therapeutic-index medicines.
Tip: Gradual dose titration; smaller meals; usually transient as the body adapts
Tip: Slow titration, hydration, dietary adjustment; report severe/persistent symptoms to a clinician
Tip: Seek care for upper-right abdominal pain, fever, or jaundice
Tip: Discontinue and seek urgent care for severe, persistent abdominal pain radiating to the back
Tip: Post-marketing reports; seek care for severe constipation, bloating, or inability to pass stool/gas
Timing is flexible for Semaglutide — consistent daily use matters more than the time of day. Subcutaneous dosing is once weekly on the same day, with or without food.
Semaglutide should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are nausea, vomiting / diarrhea / constipation, gallbladder disease (cholelithiasis / cholecystitis). Use caution if any of these apply to you: Personal or family history of medullary thyroid carcinoma (MTC); Multiple Endocrine Neoplasia syndrome type 2 (MEN2); Prior serious hypersensitivity to semaglutide or any GLP-1 receptor agonist.
Liraglutide
Mostly mechanism / observationalAn FDA-approved, once-daily GLP-1 receptor agonist (Victoza for type 2 diabetes, Saxenda for chronic weight management). Honest appraisal: a real prescription medicine with genuinely strong large-RCT evidence for glycemic control and moderate weight loss, plus a cardiovascular-outcomes benefit (LEADER). It also carries real risks — a boxed warning for thyroid C-cell tumors, pancreatitis and gallbladder risk, very common GI side effects, and lean-mass loss with weight loss. Included here for reference only; it is NOT a supplement and is not auto-recommended.
Do not combine with another GLP-1 agonist (e.g. liraglutide, dulaglutide, tirzepatide) — additive risk with no added benefit.
Tip: Resistance training and adequate protein intake during weight loss
Tip: Linked to rapid glucose lowering (SUSTAIN-6); patients with diabetic retinopathy need ophthalmologic monitoring