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A weekly shot or daily pill, FDA approved for type 2 diabetes, weight loss, heart and kidney risk, and a liver disease.
A GLP-1 receptor agonist (weekly injection or daily tablet), approved for type 2 diabetes, chronic weight management, cardiovascular and kidney risk reduction, and MASH.
Approved pens are labeled for refrigeration at 2–8 °C (36–46 °F).
Side effects and warnings
The most common side effects are nausea, throwing up, diarrhea, constipation and belly pain. They are worse at higher doses and usually happen early on.
The label has a boxed warning (the FDA's strongest warning) about thyroid tumors. This is based on studies in rats and mice. No one knows yet if it applies to people.
Other serious risks include an inflamed pancreas and gallbladder problems. It can cause sudden kidney damage, usually from losing fluids. Eye damage can get worse in some people who already have diabetic eye disease.
A summary of the sources on this page, not medical advice.
503A compounding:restricted Compounding is limited to the circumstances described under Regulatory picture; not a general permission.
Ozempic — Type 2 diabetes (US, 2017)
Ozempic — Reduce risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease (US, 2020)
Ozempic — Reduce risk of kidney function decline, kidney failure and cardiovascular death in adults with type 2 diabetes and chronic kidney disease (US, 2025)
Rybelsus — Type 2 diabetes (oral) (US, 2019)
Rybelsus — Reduce risk of major adverse cardiovascular events in adults with type 2 diabetes at high risk (oral) (US, 2025)
Ozempic tablets — Type 2 diabetes (oral; new name for a reformulated Rybelsus tablet) (US, 2026)
Wegovy — Chronic weight management in adults (US, 2021)
Wegovy — Chronic weight management in adolescents 12 and older with obesity (US, 2022)
Wegovy — Cardiovascular risk reduction in adults with CVD and overweight/obesity (US, 2024)
Wegovy — Noncirrhotic MASH with moderate to advanced fibrosis (F2–F3) (US, 2025)
Discovered by: Jesper Lau and colleagues, Novo Nordisk Global Research
Year: 2005
Developer: Novo Nordisk
What it is
Semaglutide is a lab-made copy of a gut hormone called GLP-1. Your body releases GLP-1 after you eat. It does three things. It tells the pancreas to make insulin. It slows down how fast the stomach empties. And it tells the brain that you are full. The natural hormone lasts only a couple of minutes. Semaglutide was built to last about a week. That is why the shot is given once a week.
The company Novo Nordisk sells it under several names. Ozempic is the diabetes shot. Since 2026, Ozempic is also the name of a daily diabetes tablet. Rybelsus is the first daily diabetes tablet. Wegovy is the version for weight control. It comes as a weekly shot. A higher 7.2 mg dose is sold as Wegovy HD. Since December 2025, Wegovy also comes as a daily tablet.
Semaglutide is a 31-residue GLP-1(7-37) analogue with three modifications to native GLP-1: an Aib substitution at position 8 conferring DPP-4 resistance, an Arg substitution at position 34 to prevent acylation at that lysine, and a C18 fatty diacid attached at Lys26 through a γGlu-2xOEG linker. The diacid drives high-affinity, reversible albumin binding, reducing renal clearance and yielding a plasma half-life of roughly one week. It is a full GLP-1 receptor agonist acting on pancreatic β-cells (glucose-dependent insulin secretion), α-cells (glucagon suppression), gastric motility and hypothalamic and hindbrain appetite circuits.
The oral formulations co-formulate semaglutide with SNAC (sodium N-(8-[2-hydroxybenzoyl]amino)caprylate), which locally raises gastric pH and promotes transcellular absorption across the gastric epithelium. Labeled absolute bioavailability is only about 0.4–1% for Rybelsus and 1–2% for Ozempic tablets, hence daily oral doses of 1.5–25 mg across the three tablet products, against 0.25–7.2 mg once weekly by injection.
Who made it and when
A team at Novo Nordisk, led by Jesper Lau, designed semaglutide in the mid-2000s. They wanted a longer-lasting version of the company’s older daily drug, liraglutide. The main patent was first filed in 2005. The team published how they designed it in 2015. Ozempic was approved in 2017. Rybelsus followed in 2019, and Wegovy in 2021. The company owns the main patents. In the United States, these last into the early 2030s.
Semaglutide emerged from Novo Nordisk’s programme to extend the albumin-binding strategy used in liraglutide. Lau and colleagues described the structure–activity work in the Journal of Medicinal Chemistry in 2015. The compound patent, US 8,129,343 (priority March 2005, granted 2012), is held by Novo Nordisk; regulatory exclusivity and secondary formulation and dosing patents extend protection beyond the compound patent in most markets. US approvals: Ozempic 2017-12-05, Rybelsus 2019-09-20, Wegovy 2021-06-04, Wegovy tablets 2025-12-22 and the Wegovy 7.2 mg dose 2026-03-19. In January 2026 the FDA approved renaming a reformulated Rybelsus tablet (1.5, 4 and 9 mg) as Ozempic tablets.
What the data say
The big studies agree with each other. Some tested people with obesity who did not have diabetes. In them, the 2.4 mg weekly dose cut body weight by about 15% over 16 months. People on a dummy treatment (placebo) lost about 2%. Another study looked at people who already had heart disease. It found about one fifth fewer heart attacks, strokes and deaths from heart and blood vessel disease. The drug also protected the kidneys in people with diabetes. It eased liver inflammation in MASH (a type of fatty liver disease). A higher 7.2 mg dose led to about 19% weight loss. The 2.4 mg dose led to about 16%. Two large Alzheimer’s studies of the tablet failed.
STEP 1 (n=1,961) reported a treatment difference of −12.4 percentage points in body weight at 68 weeks. SELECT (n=17,604) reported a hazard ratio of 0.80 for 3-point MACE over a mean 39.8 months. FLOW (n=3,533) reported a hazard ratio of 0.76 for the composite kidney outcome and was stopped early for efficacy. ESSENCE part 1 (first 800 of 1,197 participants) met both histological primary endpoints at 72 weeks. STEP UP (n=1,407) reported −18.7% with 7.2 mg vs −15.6% with 2.4 mg and −3.9% with placebo at 72 weeks (treatment-policy estimand), with dysaesthesia in 22.9% of the 7.2 mg group. EVOKE and EVOKE+ (n=3,808 combined) found no difference from placebo in CDR-SB change at 104 weeks despite improvements in Alzheimer’s biomarkers.
Regulatory picture
Semaglutide is fully approved by the FDA under its brand names. Versions made by anyone else are not approved. From 2022–2025 there was a shortage of the drug. During that time, special pharmacies (compounding pharmacies) were allowed to make copies. In February 2025 the FDA said the shortage was over. It gave these pharmacies deadlines in April and May 2025 to stop. Since then, the FDA has sent warning letters to sellers of “compounded” or “research” semaglutide. In February 2026 it said it would take steps to limit the raw ingredient used in mass-sold copies.
Semaglutide is not on the 503A bulk drug substances list and does not need to be, because it is a component of FDA-approved drugs. Compounding of essentially-copies of an approved product is permitted only while the product appears on the FDA drug shortage list under section 503A(b)(1)(D) and 503B(a)(2)(A). With the shortage removed on 2025-02-21, that pathway closed on 2025-04-22 for 503A and 2025-05-22 for 503B; FDA confirmed in April 2026 that semaglutide is on neither the shortage list nor the 503B bulks list. FDA states it is aware of no lawful basis for compounding with semaglutide sodium or semaglutide acetate, which are different active ingredients from the approved drug. Personalised compounded formulations that differ materially from the approved product remain a contested area, and FDA’s February 2026 announcement signalled tighter control of GLP-1 active ingredients destined for non-approved compounded drugs.
Dose
Doses reported in trials and studies
How dosing worked in the studies
In STEP 1, 1,961 adults with obesity or overweight plus another health problem were assigned by chance to semaglutide or a dummy treatment (placebo). They got a shot under the skin once a week for 68 weeks. The dose started at 0.25 mg and went up over 16 weeks to a goal of 2.4 mg. SELECT included 17,604 adults with heart and blood vessel disease, at 2.4 mg once a week. FLOW included 3,533 adults with type 2 diabetes and long-term kidney disease, at 1.0 mg once a week. In STEP UP, 1,407 adults were assigned by chance to 7.2 mg, 2.4 mg or placebo once a week for 72 weeks. Tablet studies compared placebo with daily doses. In OASIS 1, the dose went up to a goal of 50 mg for 68 weeks. In EVOKE, doses were flexible, up to 14 mg.
Label dosing (FDA-approved products)
The Wegovy label starts the injection at 0.25 mg subcutaneously once weekly (weeks 1 through 4), then 0.5 mg (weeks 5 through 8), 1 mg (weeks 9 through 12) and 1.7 mg (weeks 13 through 16). If a dose is not tolerated during escalation, the label says to consider delaying escalation for 4 weeks. For weight reduction or cardiovascular risk reduction in adults, the maintenance dosage is 2.4 mg (recommended) or 1.7 mg once weekly. For weight reduction, patients who tolerate 2.4 mg for at least 4 weeks and need more weight loss may go up to a maximum of 7.2 mg once weekly. Wegovy tablets (cardiovascular risk reduction or weight reduction in adults) start at 1.5 mg orally once daily (days 1 through 30), then 4 mg (days 31 through 60) and 9 mg (days 61 through 90), with a maintenance dosage of 25 mg once daily. (Wegovy (semaglutide) injection and tablets prescribing information, FDA label rev. 06/2026)
The Ozempic label starts at 0.25 mg injected subcutaneously once weekly for 4 weeks, then 0.5 mg once weekly. The recommended maintenance dosage is 0.5 mg, 1 mg or 2 mg once weekly based on glycemic control. If more glycemic control is needed after at least 4 weeks on 0.5 mg, the dose may go to 1 mg, and after at least 4 weeks on 1 mg, to 2 mg. The maximum recommended dosage is 2 mg once weekly. In type 2 diabetes with chronic kidney disease, the label's maintenance dosage is 1 mg once weekly, reached after at least 4 weeks on 0.5 mg. (Ozempic (semaglutide) injection prescribing information, FDA label rev. 05/2026)
Doses reported in studies, exactly as the cited trial reported them. They are not personal dosing instructions. Population, route and schedule matter more than the number.
STEP 1: 1,961 adults with obesity or overweight plus comorbidity, no diabetes. Dose: 2.4 mg subcutaneous once weekly, titrated from 0.25 mg over 16 weeks, 68 weeks total. Result: −14.9% body weight vs −2.4% placebo at 68 weeks (Wilding et al., NEJM 2021)
SELECT: 17,604 adults with established cardiovascular disease and overweight/obesity, no diabetes. Dose: 2.4 mg subcutaneous once weekly. Result: 20% relative reduction in major adverse cardiovascular events over a mean 39.8 months of follow-up (Lincoff et al., NEJM 2023)
FLOW: 3,533 adults with type 2 diabetes and chronic kidney disease. Dose: 1.0 mg subcutaneous once weekly. Result: 24% reduction in major kidney disease events; stopped early for efficacy (Perkovic et al., NEJM 2024)
ESSENCE: 1,197 adults with biopsy-confirmed MASH and fibrosis stage 2–3 (part 1 analysis in the first 800). Dose: 2.4 mg subcutaneous once weekly vs placebo, planned 240 weeks. Result: Part 1 at 72 weeks: resolution of steatohepatitis without worsening fibrosis in 62.9% vs 34.3% placebo (Sanyal et al., NEJM 2025)
STEP UP: 1,407 adults with obesity (BMI 30 or higher), no diabetes. Dose: 7.2 mg or 2.4 mg subcutaneous once weekly vs placebo, 72 weeks. Result: −18.7% body weight at 7.2 mg vs −15.6% at 2.4 mg and −3.9% placebo, treatment-policy estimand (Wharton et al., Lancet Diabetes Endocrinol 2025)
EVOKE: 1,855 adults aged 55–85 with amyloid-confirmed mild cognitive impairment or mild dementia due to Alzheimer's disease. Dose: Oral semaglutide up to 14 mg once daily (flexible dose) vs placebo. Result: Did not slow decline on CDR-SB at 104 weeks vs placebo, nor did the companion EVOKE+ trial (Novo Nordisk, November 2025; Cummings et al., Lancet 2026)
1,855 adults aged 55–85 with amyloid-confirmed mild cognitive impairment or mild dementia due to Alzheimer's disease
Oral semaglutide up to 14 mg once daily (flexible dose) vs placebo
Did not slow decline on CDR-SB at 104 weeks vs placebo, nor did the companion EVOKE+ trial (Novo Nordisk, November 2025; Cummings et al., Lancet 2026)
Doses in other published studies
Published studies not listed in the trials table above: smaller or unregistered human studies first, then animal and cell studies. Doses are shown exactly as each study reported them. Animal studies report weight-based doses, absolute amounts or concentrations; none translates directly to people, and none is converted here.
Subjects
Design
Dose
Finding
Source
Humans: 957 adults with obesity (BMI 30 kg/m2 or more) without diabetes
Randomized, double-blind, placebo- and liraglutide-controlled, multicentre, dose-ranging phase 2
Semaglutide 0.05 mg, 0.1 mg, 0.2 mg, 0.3 mg or 0.4 mg subcutaneous once daily (initiated at 0.05 mg per day and escalated every 4 weeks), 52 weeks, with diet and physical activity counselling
Estimated mean weight change at week 52 was -6.0% (0.05 mg), -8.6% (0.1 mg), -11.6% (0.2 mg), -11.2% (0.3 mg) and -13.8% (0.4 mg) vs -2.3% with placebo; all doses differed significantly from placebo, and the most common adverse events were dose-related GI symptoms, mainly nausea.
Semaglutide subcutaneous once weekly, 0.1-0.8 mg without dose escalation, or 0.8 or 1.6 mg reached in 0.4 mg escalation steps over 1-2 weeks; 12 weeks
At week 12 semaglutide reduced HbA1c dose-dependently by up to -1.7% and body weight by up to -4.8 kg (1.6 mg escalated arm); nausea, vomiting and withdrawals due to GI adverse events increased with dose, and 0.5 and 1.0 mg weekly with a 4-week escalation were selected for phase 3.
Semaglutide subcutaneous 0.25 mg/week for 4 weeks, 0.5 mg/week for 4 weeks, and 1.0 mg for 1 week (9 weeks), given at weekly clinic visits; primary outcome measured at 0.5 mg/week
Compared with placebo, the low-dose schedule reduced grams of alcohol consumed in a posttreatment laboratory self-administration task, drinks per drinking day and weekly craving, but did not change drinks per calendar day or number of drinking days.
Semaglutide 2.4 mg or 1.0 mg subcutaneous once weekly, 68 weeks, plus lifestyle intervention
Estimated body weight change at week 68 was -9.6% with 2.4 mg vs -3.4% with placebo; GI adverse events occurred in 63.5% (2.4 mg), 57.5% (1.0 mg) and 34.3% (placebo).
Humans: 245 adults with type 2 diabetes and BMI 27 kg/m2 or more on metformin
Randomized, parallel-group, participant- and investigator-blinded, placebo-controlled phase 2
Semaglutide 2 mg, 8 mg or 16 mg subcutaneous once weekly, escalated every 4 weeks then maintained, 40 weeks
For 16 mg vs 2 mg the estimated treatment difference (treatment-policy estimand) was -3.4 kg for weight (P = 0.011) and -0.3 percentage points for HbA1c (P = 0.245, not significant); adverse events and discontinuations due to adverse events, mainly GI, were more frequent at 8 and 16 mg than at 2 mg.
Examples for the freeze-dried powder, as reported by protocol websites, not taken from studies. The water amount only sets the concentration (how much is in each mL); it does not change how much of the compound is in the vial. Each concentration assumes the vial really holds its labelled amount and the final liquid volume equals the water added.
Vial
Water added
Concentration
5 mg
2.0 mL
2.5 mg/mL
10 mg
3.0 mL
about 3.33 mg/mL
5 mg
1.0 mL
5.0 mg/mL
Clean the rubber tops of both vials with an alcohol swab.
Add the water slowly, letting it run down the inside wall of the vial rather than onto the powder.
Swirl or roll gently until the powder dissolves; protocol sites advise against shaking.
The liquid should be clear. If it is cloudy or has specks in it, do not use it. Clear liquid does not show that the product is pure, the right strength or sterile.
Write the date and the concentration on the vial, and keep it in the fridge (2–8 °C). No safe storage time after mixing has been established for these products.
Products sold as "research peptides" have not gone through FDA review for safety, effectiveness or quality. Bacteriostatic water does not sterilize a contaminated powder. It contains benzyl alcohol, and its label says it is not for use in newborns. To work out a volume from your own numbers, use the converter.
Doses described in clinical or compounding practice
From FDA labels and documents, other regulators, published reviews and professional references, as each source states them. Unless a source says otherwise, these describe practice or proposals, not results tested in trials. Reading doses safely: how concentration and syringe markings work.
The Wegovy label starts the injection at 0.25 mg subcutaneously once weekly (weeks 1 through 4), then 0.5 mg (weeks 5 through 8), 1 mg (weeks 9 through 12) and 1.7 mg (weeks 13 through 16). If a dose is not tolerated during escalation, the label says to consider delaying escalation for 4 weeks. For weight reduction or cardiovascular risk reduction in adults, the maintenance dosage is 2.4 mg (recommended) or 1.7 mg once weekly. For weight reduction, patients who tolerate 2.4 mg for at least 4 weeks and need more weight loss may go up to a maximum of 7.2 mg once weekly. Wegovy tablets (cardiovascular risk reduction or weight reduction in adults) start at 1.5 mg orally once daily (days 1 through 30), then 4 mg (days 31 through 60) and 9 mg (days 61 through 90), with a maintenance dosage of 25 mg once daily. (Wegovy (semaglutide) injection and tablets prescribing information, FDA label rev. 06/2026, FDA label)
The Ozempic label starts at 0.25 mg injected subcutaneously once weekly for 4 weeks, then 0.5 mg once weekly. The recommended maintenance dosage is 0.5 mg, 1 mg or 2 mg once weekly based on glycemic control. If more glycemic control is needed after at least 4 weeks on 0.5 mg, the dose may go to 1 mg, and after at least 4 weeks on 1 mg, to 2 mg. The maximum recommended dosage is 2 mg once weekly. In type 2 diabetes with chronic kidney disease, the label's maintenance dosage is 1 mg once weekly, reached after at least 4 weeks on 0.5 mg. (Ozempic (semaglutide) injection prescribing information, FDA label rev. 05/2026, FDA label)
FDA's May 2026 notice proposes not to add semaglutide to the 503B bulks list. It records that nominators proposed compounded subcutaneous injection, sublingual, buccal and oral products in strengths that vary "depending on medical provider requests", including 25 mg and 50 mg oral tablets and capsules. Nominators argued that some "hyper-responders" may need a slower titration or a lower maintenance dose, and one nominator (BPI Labs) referred to "microdosing" to control side effects. FDA notes that another nominator (OFA) did not identify alternative doses. FDA said the nominations did not explain why the approved lower-concentration products (0.25 mg/0.5 mL, 0.5 mg/0.5 mL, 1 mg/0.5 mL) or a slower titration using approved products could not be used. It cited the Wegovy label's advice to consider delaying dose escalation for 4 weeks. (FDA, List of Bulk Drug Substances for Which There Is a Clinical Need Under Section 503B (Federal Register, May 1, 2026), FDA document)
This retrospective study covered 206 adults prescribed semaglutide injections for weight management at one Danish general practice. At 12 months, 38% had permanently stopped and approximately 48% were still on treatment. Of those still on treatment, 40% were on ≤ 1.0 mg/week, 30% on 1.7 mg/week and 30% on 2.4 mg/week. The authors conclude that in real-world practice semaglutide was titrated more slowly and to lower maintenance doses than the approved labelling. This is observational data from a single practice, not a dosing recommendation. (Skandov MD et al. Real-World Use of Semaglutide for Weight Management: Dose Titration, Discontinuation Patterns and Weight Changes. Diabetes Obes Metab 2026, Peer-reviewed)
Doses reported in online communities (untested)
Unverified, and not a recommendation. These are amounts people describe in online forums such as Reddit, collected so researchers can see how practice differs from the evidence. These forum accounts are not clinical evidence, even where they overlap studied doses. Products sold online as "research peptides" are not FDA approved, and their identity, purity and strength are not verified; they can be mislabeled, contaminated or wrongly dosed.
What people report
In the threads reviewed, "microdosing" covers two practices: single subcutaneous amounts of about 0.1 to 0.15 mg taken weekly or less often, and split dosing, where a weekly amount of about 0.25 to 0.5 mg is divided into injections every 2 to 5 days. The main disagreement is whether amounts below 0.25 mg do anything; several commenters say they are not therapeutic. The side effects posters describe trying to reduce are nausea, tiredness and end-of-week hunger.
How this compares with the studies
Weekly amounts of 0.25-0.5 mg sit inside labeled weekly doses (0.25 mg up to 2.4 mg) and overlap lower trial doses (Hendershot 2025). Amounts of 0.1-0.15 mg overlap only the lowest Nauck 2016 arm (0.1 mg weekly), and nothing lower was tested in the studies found. Threads trace their numbers to fractions of the 0.25 mg starting dose, pen click charts, provider advice and a fitness YouTuber's chart, not published studies.
Open questions a study would need to answer
Is there a minimum effective weekly dose below 0.25 mg for appetite, weight or metabolic markers versus placebo over 6 months or longer?
Does dividing the same weekly amount into more frequent injections change exposure, GI tolerability or weight outcomes compared with once-weekly dosing, given a half-life of about one week?
How accurate and pure are doses taken from compounded or non-approved products of unstated concentration, and do the non-weight effects reported at low doses (less drinking, joint pain, mood) show up under placebo control?
2025-02-21 · Shortage resolved: FDA declared the semaglutide injection shortage resolved. Enforcement discretion for copies ended 2025-04-22 for 503A pharmacies and 2025-05-22 for 503B outsourcing facilities. (source)
2025 · Warning letters: FDA reports warning letters to companies selling semaglutide labelled "for research purposes" or "not for human consumption", and (fall 2025) to firms over misleading marketing of compounded GLP-1 drugs. FDA also states it knows of no lawful basis for compounding with semaglutide salt forms (sodium, acetate). (source)
2026-02-06 · Enforcement announcement: FDA announced it intends to restrict GLP-1 active ingredients intended for non-FDA-approved compounded drugs and to act against claims that compounded products are the same as, or generic versions of, approved drugs. (source)
2026-09-18 · Warning letter: FDA told Empower Pharmacy (Houston, a 503A pharmacy) that its semaglutide/cyanocobalamin product appeared to be essentially a copy of an approved drug, compounded regularly and in inordinate amounts, that prescriber statements of a significant difference appeared pretextual, and cited insanitary conditions. The letter restates that enforcement discretion for compounded semaglutide ended on 2025-04-24. (source)
Side effects and warnings
The most common side effects are nausea, throwing up, diarrhea, constipation and belly pain. They are worse at higher doses and usually happen early on.
The label has a boxed warning (the FDA's strongest warning) about thyroid tumors. This is based on studies in rats and mice. No one knows yet if it applies to people.
Other serious risks include an inflamed pancreas and gallbladder problems. It can cause sudden kidney damage, usually from losing fluids. Eye damage can get worse in some people who already have diabetic eye disease.
Blood sugar can drop too low if it is used with insulin or certain other diabetes pills (sulfonylureas).
It slows how fast the stomach empties. This can change how other pills are taken up. There is also a risk of breathing in stomach contents during surgery with anesthesia.
It should not be used by people with a personal or family history of a certain thyroid cancer (medullary thyroid carcinoma) or MEN 2. It should also not be used after a past serious allergic reaction to it. Labels say to stop at least two months before a planned pregnancy.
Full lists are in the .
Reported side effects
Nausea, vomiting, diarrhea, constipation and abdominal pain (most common; dose-dependent, usually early)
Boxed warning for thyroid C-cell tumors, based on rodent studies; human relevance unknown
Pancreatitis
Gallbladder disease, including cholelithiasis
Hypoglycemia when combined with insulin or sulfonylureas
Acute kidney injury, usually secondary to dehydration from GI effects
Worsening of diabetic retinopathy in some patients with pre-existing disease
Pulmonary aspiration during general anesthesia or deep sedation (label warning)
Dysesthesia (altered skin sensation) listed among common reactions in the current Wegovy label, reported mainly at the 7.2 mg dose
Non-arteritic anterior ischemic optic neuropathy (NAION), concluded by the EMA safety committee in June 2025 to be a very rare side effect
Injection-site reactions, fatigue, dysgeusia
Interactions
Insulin and insulin secretagogues (sulfonylureas): labels warn of a higher risk of hypoglycemia
Oral medications: delayed gastric emptying may alter absorption; labels advise monitoring, especially for narrow-therapeutic-index drugs. Levothyroxine exposure rose 33% with oral semaglutide in an interaction study; warfarin pharmacokinetics were not meaningfully changed
Oral contraceptives: no clinically meaningful interaction with semaglutide, unlike tirzepatide
Contraindications
Personal or family history of medullary thyroid carcinoma
Multiple endocrine neoplasia syndrome type 2 (MEN 2)
Prior serious hypersensitivity reaction to semaglutide or excipients
Pregnancy: labels advise discontinuing at least two months before a planned pregnancy
Storage
Unopened: Approved pens are labeled for refrigeration at 2–8 °C (36–46 °F). Do not freeze. Protect from light.
Reconstituted / in use: After first use an Ozempic pen is labeled for up to 56 days at 15–30 °C or refrigerated. Wegovy single-dose pens and syringes may be kept at 8–30 °C for up to 28 days before the cap is removed.
Research-grade lyophilized powder is typically shipped and stored frozen at −20 °C. Once dissolved, suppliers generally state 2–8 °C and short-term use. Those figures are supplier claims, not label data.
Product characteristics
Form: Solution for subcutaneous injection (pre-filled pen or syringe) or oral tablet with SNAC absorption enhancer; research grade sold as lyophilized powder
Appearance: Clear, colorless solution; white to off-white lyophilized powder
Solubility: Soluble in water and aqueous buffers near neutral pH
Stability: Strong albumin binding via the C18 fatty diacid gives a half-life of about one week
Compound information
Synthetic 31-residue lipidated peptide. The linked Cayman Chemical SDS covers its research-grade semaglutide (acetate) and states the substance is not classified under GHS; FDA treats salt forms as different active ingredients from the approved drug. Handle as a bioactive peptide; avoid inhalation of powder.
Molecule, patents, enforcement history, full trial tables and compound details are in the .
Patents
US 8,129,343 · Novo Nordisk · Acylated GLP-1 compounds (core semaglutide compound patent)
Common questions
What is Semaglutide?
Semaglutide is a lab-made copy of a gut hormone called GLP-1. Your body releases GLP-1 after you eat. It does three things. It tells the pancreas to make insulin. It slows down how fast the stomach empties. And it tells the brain that you are full. The natural hormone lasts only a couple of minutes. Semaglutide was built to last about a week. That is why the shot is given once a week.
Is Semaglutide FDA approved?
FDA approved as Ozempic, Rybelsus and Wegovy, for type 2 diabetes, weight management, lowering heart and kidney risks in certain adults, and treating MASH liver disease with fibrosis (accelerated approval).
What have studies found?
In large studies, weekly shots led to about 15% to 19% weight loss. They also meant fewer heart attacks and strokes in people with heart disease, and better kidney and liver results.
The main side effects were stomach problems, mostly nausea, and they were more common at higher doses. The tablet did not slow Alzheimer's disease.
How was it dosed in studies?
In STEP 1, 1,961 adults with obesity or overweight plus another health problem were assigned by chance to semaglutide or a dummy treatment (placebo). They got a shot under the skin once a week for 68 weeks. The dose started at 0.25 mg and went up over 16 weeks to a goal of 2.4 mg. SELECT included 17,604 adults with heart and blood vessel disease, at 2.4 mg once a week. FLOW included 3,533 adults with type 2 diabetes and long-term kidney disease, at 1.0 mg once a week. In STEP UP, 1,407 adults were assigned by chance to 7.2 mg, 2.4 mg or placebo once a week for 72 weeks. Tablet studies compared placebo with daily doses. In OASIS 1, the dose went up to a goal of 50 mg for 68 weeks. In EVOKE, doses were flexible, up to 14 mg.
What are the side effects and warnings?
The most common side effects are nausea, throwing up, diarrhea, constipation and belly pain. They are worse at higher doses and usually happen early on.
The label has a boxed warning (the FDA's strongest warning) about thyroid tumors. This is based on studies in rats and mice. No one knows yet if it applies to people.
Other serious risks include an inflamed pancreas and gallbladder problems. It can cause sudden kidney damage, usually from losing fluids. Eye damage can get worse in some people who already have diabetic eye disease.
Blood sugar can drop too low if it is used with insulin or certain other diabetes pills (sulfonylureas).
It slows how fast the stomach empties. This can change how other pills are taken up. There is also a risk of breathing in stomach contents during surgery with anesthesia.
It should not be used by people with a personal or family history of a certain thyroid cancer (medullary thyroid carcinoma) or MEN 2. It should also not be used after a past serious allergic reaction to it. Labels say to stop at least two months before a planned pregnancy.
References
This page summarises the published sources below. PeptideBasics101 does no original research. Trial doses and results are reported as the cited study or label reported them. Sources can themselves be wrong or superseded; if you find a statement here that does not match its source, please tell us through our corrections process. Sources were last checked on 2026-11-01.
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