Semaglutide: Difference between revisions

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| onset = Glycemic effect within days;{{Citation needed}} full weight effect over months<ref name="step1">Wilding JPH et al. (2021). Once-weekly semaglutide in adults with overweight or obesity (STEP-1). ''NEJM'' 384:989. doi:10.1056/NEJMoa2032183</ref>

| duration = ~7 days (weekly SC dosing)<ref name="ozempic-label"/> · ~24 h (oral)<ref name="rybelsus-label"/>

| halflife = ~165 hours (~1 week) — among the longest of any GLP-1 RA<ref name="lau2015"/>

| halflife = ~165 hours (~1 week), among the longest of any GLP-1 RA<ref name="lau2015"/>

| bioavailability = SC ~89%{{Citation needed}} · Oral ~0.4–1% (SNAC-enhanced)<ref name="rybelsus-label"/>

| pregnancy = Avoid. Discontinue ≥2 months before planned pregnancy due to long half-life. Animal data show embryofetal harm.<ref name="ozempic-label"/> Not contraceptive — but rapid weight loss + improved ovulation may unmask fertility in [[PCOS]].{{Citation needed}}

| pregnancy = Avoid. Discontinue ≥2 months before planned pregnancy due to long half-life. Animal data show embryofetal harm.<ref name="ozempic-label"/> Not contraceptive, but rapid weight loss + improved ovulation may unmask fertility in [[PCOS]].{{Citation needed}}

| legal = Rx-only;<ref name="ozempic-label"/> not a controlled substance

| intro = Semaglutide is a long-acting [[GLP-1 receptor agonist]] developed by [[Novo Nordisk]], marketed as '''[[Ozempic]]''' (weekly subcutaneous, for [[type 2 diabetes mellitus]]),<ref name="ozempic-label"/> '''[[Wegovy]]''' (weekly subcutaneous, for [[obesity]], [[cardiovascular risk reduction]] in obesity without diabetes, and [[MASH]] with fibrosis),<ref name="wegovy-label"/><ref name="select">Lincoff AM et al. (2023). Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT). ''NEJM'' 389:2221–32. doi:10.1056/NEJMoa2307563</ref><ref name="essence">Newsome PN et al. (2025). Semaglutide in MASH (ESSENCE). FDA approval basis. {{Citation needed}}</ref> and '''[[Rybelsus]]''' (daily oral tablet, for T2DM).<ref name="rybelsus-label"/> It is, by revenue, among the highest-grossing medicines on the planet as of 2024.{{Citation needed}}

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Acylation with a C18 fatty diacid drives non-covalent binding to serum albumin, slowing renal clearance and DPP-4 access. The Aib8 substitution renders the peptide DPP-4-resistant. Resulting terminal half-life ~165 h means once-weekly subcutaneous dosing produces near-steady-state plasma levels.<ref name="lau2015"/>

Oral semaglutide (Rybelsus) is co-formulated with '''SNAC''' (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate), a permeation enhancer that transiently raises gastric pH and protects the peptide locally — yielding ~0.4–1% bioavailability, which is sufficient at 14 mg daily to match Ozempic 0.5 mg weekly for glycemic effect (but not for weight loss).<ref name="rybelsus-label"/><ref name="buckley2018">Buckley ST, Bækdal TA, Vegge A et al. (2018). Transcellular stomach absorption of a derivatized glucagon-like peptide-1 receptor agonist. ''Sci Transl Med'' 10(467):eaar7047. doi:10.1126/scitranslmed.aar7047</ref> Strict fasting administration is mandatory; any concurrent food or beverage destroys absorption.<ref name="rybelsus-label"/>

Oral semaglutide (Rybelsus) is co-formulated with '''SNAC''' (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate), a permeation enhancer that transiently raises gastric pH and protects the peptide locally, yielding ~0.4–1% bioavailability, which is sufficient at 14 mg daily to match Ozempic 0.5 mg weekly for glycemic effect (but not for weight loss).<ref name="rybelsus-label"/><ref name="buckley2018">Buckley ST, Bækdal TA, Vegge A et al. (2018). Transcellular stomach absorption of a derivatized glucagon-like peptide-1 receptor agonist. ''Sci Transl Med'' 10(467):eaar7047. doi:10.1126/scitranslmed.aar7047</ref> Strict fasting administration is mandatory; any concurrent food or beverage destroys absorption.<ref name="rybelsus-label"/>

Predominantly catabolic clearance via proteolysis; renal and hepatic impairment do not require dose adjustment.<ref name="ozempic-label"/> No CYP-mediated metabolism, so the interaction profile is dominated by ''gastric emptying'' effects on other oral medicines, not pharmacokinetic competition.<ref name="ozempic-label"/>

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| dosing = <titration slug="ozempic-standard" author="MDElliottMD" title="Ozempic — standard T2DM titration">

| dosing = <titration slug="ozempic-standard" author="MDElliottMD" title="Ozempic, standard T2DM titration">

0.25 mg SC weekly × 4 weeks (non-therapeutic; tolerance ramp only)

→ 0.5 mg SC weekly × ≥4 weeks

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→ 2 mg SC weekly (max) if needed<ref name="ozempic-label"/>

Slower titration is reasonable in any patient with significant GI symptoms — holding at a tolerated dose for 8–12 weeks before advancing is standard practice.

Slower titration is reasonable in any patient with significant GI symptoms, holding at a tolerated dose for 8–12 weeks before advancing is standard practice.

</titration>

0.25 mg SC weekly × 4 weeks

→ 0.5 mg × 4 weeks

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</titration>

3 mg PO daily × 30 days (non-therapeutic ramp)

→ 7 mg PO daily × ≥30 days

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| effects = Subjective effects vary considerably with dose and titration speed but reliably include:

* '''Early satiety''' — meals feel "complete" at a fraction of prior intake<ref name="step1"/>

* '''Early satiety''', meals feel "complete" at a fraction of prior intake<ref name="step1"/>

* '''Food noise quieting''' — the most commonly volunteered subjective change. Patients report that intrusive food-related thoughts simply stop.{{Citation needed}}

* '''Food noise quieting''', the most commonly volunteered subjective change. Patients report that intrusive food-related thoughts simply stop.{{Citation needed}}

* '''Reduced alcohol craving''' — corroborated by observational and small RCT data; mechanism likely shared with food reward circuitry<ref name="wang2024">Wang W, Volkow ND, Berger NA et al. (2024). Associations of semaglutide with incidence and recurrence of alcohol use disorder in real-world population. ''Nat Commun'' 15:4548. doi:10.1038/s41467-024-48780-6</ref>

* '''Reduced alcohol craving''', corroborated by observational and small RCT data; mechanism likely shared with food reward circuitry<ref name="wang2024">Wang W, Volkow ND, Berger NA et al. (2024). Associations of semaglutide with incidence and recurrence of alcohol use disorder in real-world population. ''Nat Commun'' 15:4548. doi:10.1038/s41467-024-48780-6</ref>

* '''Nausea''' — dose-dependent, worst in first 1–2 weeks of any new dose level<ref name="ozempic-label"/>

* '''Nausea''', dose-dependent, worst in first 1–2 weeks of any new dose level<ref name="ozempic-label"/>

* '''Constipation or diarrhea''' (variable, can alternate)<ref name="ozempic-label"/>

* '''Sulfurous eructation''' (a small but very real subgroup){{Citation needed}}

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Importantly: semaglutide is '''not a contraceptive''', and the medicine may '''restore ovulation''' in patients with [[PCOS]] or [[obesity]]-associated anovulation.{{Citation needed}} Patients of childbearing potential should be counseled about contraception ''before'' starting.

| monitoring = * Baseline: HbA1c, weight, BP, renal function, lipid panel, [[ALT]]/AST (especially for MASH ~~indication~~)

| monitoring = * Baseline: HbA1c, weight, BP, renal function, lipid panel, [[ALT]]/AST (especially for MASH problem)

* Personal or family history of MTC or [[MEN2]] — '''contraindicated''', do not start<ref name="ozempic-label"/>

* Personal or family history of MTC or [[MEN2]], '''contraindicated''', do not start<ref name="ozempic-label"/>

* Every 3 months for first year: HbA1c, weight, GI tolerability, signs of [[pancreatitis]] or [[gallbladder disease]]

* Annual: renal function, lipids

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* Inject SC in abdomen, thigh, or upper arm; rotate sites. Pen is single-patient, multi-dose.<ref name="ozempic-label"/>

* GI side effects almost always peak in first 2–4 weeks of any new dose level, then attenuate.<ref name="ozempic-label"/>

* Eat smaller portions earlier in the day. Plate sizes will feel comically large after a few weeks — that is the medicine working, not a problem to fix.

* Eat smaller portions earlier in the day. Plate sizes will feel comically large after a few weeks, that is the medicine working, not a problem to fix.

* Hydrate aggressively (volume depletion → AKI is a real risk).<ref name="ozempic-label"/>

* Resistance training during weight loss protects lean mass and is strongly encouraged.{{Citation needed}}

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}}

~~[[Category:MedCategory]]~~

[[Category:GLP-1 receptor agonists]]

[[Category:Antidiabetic medicines]]

[[Category:Anti-obesity medicines]]

[[Category:Novo Nordisk medicines]]

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