Semaglutide: research

A GLP-1 medicine with strong weight, glucose, heart and kidney evidence; dose and formulation matter.

Also called: Ozempic, Wegovy, Wegovy HD, Wegovy FlexTouch, Rybelsus, oral semaglutide, NN9535, NN9924.

GLP-1 / GIP / glucagon agonists · GLP-1 receptor agonist · Evidence: Approved drug.

642 registered interventional records include ongoing and comparator trials. Pivotal studies support major uses; this count is not 642 completed efficacy trials.

Studies

Semaglutide dosage

Typical reported dose: 0.25 mg once a week to start, up to 2.4 mg

  • Ozempic injection: 0.5–2 mg: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly, then 2 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults in the product’s approved population. (source)
  • Ozempic: kidney-risk indication: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults with diabetes and chronic kidney disease. (source)
  • Wegovy: weight maintenance: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly, then 1.7 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults in the product’s approved population. (source)
  • Wegovy: cardiovascular risk: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly, then 1.7 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults in the product’s approved population. (source)
  • Wegovy: noncirrhotic MASH: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly, then 1.7 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults in the product’s approved population. (source)
  • Wegovy: 1.7 mg maintenance: 0.25 mg once weekly, then 0.5 mg once weekly, then 1 mg once weekly, then 1.7 mg once weekly once weekly, under the skin. Drug label. Studied in: Adults in the product’s approved population. (source)

Highest studied: Highest verified human weekly arm: 16 mg nominal, 16.13 mg delivered; approved limits are lower.; Highest verified daily oral efficacy dose: 50 mg; also EU-labeled for diabetes..

These are doses reported in labels, trials or user reports, not a personal plan. Check the source behind each one.

Work out syringe units with the dosing calculator

Semaglutide side effects and risks

Reported side effects

  • US boxed warning: thyroid C-cell tumors: Semaglutide caused thyroid C cell tumors in rodents. Whether it causes these tumors in humans is unknown., serious. Avoid with personal or family MTC or MEN2. Report a neck lump, trouble swallowing or persistent hoarseness. (source)
  • Nausea: 2.4 mg injection: 44% versus 16% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Diarrhea: 2.4 mg injection: 30% versus 16% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Vomiting: 2.4 mg injection: 24% versus 6% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Constipation: 2.4 mg injection: 24% versus 11% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Abdominal pain: 2.4 mg injection: 20% versus 10% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Headache: 2.4 mg injection: 14% versus 10% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Fatigue: 2.4 mg injection: 11% versus 5% placebo., moderate. Smaller meals and fluids may help; persistent or severe symptoms need review. (source)
  • Burping, reflux or indigestion: 2.4 mg: burping 7%, reflux 5%, indigestion 9%; placebo <1%, 3%, 3%., moderate (source)
  • Hair loss: 2.4 mg: 3% versus 1% placebo; 7.2 mg: 6% versus 1% placebo., moderate (source)
  • Altered or painful skin sensation: Pooled 7.2/2.4 mg/placebo: 22%/6%/0.3%., moderate. Report lasting burning, numbness or painful touch; a dose change may be needed. (source)
  • Gallstones: 2.4 mg injection: 1.6% versus 0.7% placebo; oral Wegovy: 2.5% versus 1%., serious (source)
  • Gallbladder inflammation: 2.4 mg injection: 0.6% versus 0.2% placebo., serious (source)
  • Low blood sugar: Wegovy in diabetes, without insulin: 6.2% versus 2.5% placebo below 54 mg/dL., serious. Risk rises with insulin or sulfonylureas; those medicines may need adjustment. (source)

Stop and get help if

  • Severe lasting upper abdominal pain, with or without vomiting: Stop semaglutide and get urgent assessment for pancreatitis.
  • Face or throat swelling, breathing trouble or fainting: Stop the drug and call emergency services for possible severe allergy.
  • Sudden vision loss or rapidly worsening sight: Get urgent eye care today; confirmed NAION requires stopping semaglutide.
  • Confusion, seizure, unconsciousness or low sugar that will not resolve: Call emergency services; severe low blood sugar needs immediate care.
  • Repeated vomiting, inability to drink, or very little urine: Get urgent care for dehydration, kidney injury or overdose.
  • Severe bloating, vomiting, and no stool or gas: Get urgent care for possible bowel obstruction.
  • Right upper abdominal pain with fever, jaundice or pale stool: Get urgent assessment for gallbladder or bile-duct disease.
  • Chest pain, fainting or persistent racing heart at rest: Seek urgent care; call emergency services for chest pain or collapse.

Who should avoid it

  • mtcOrMen2: US labels contraindicate use with personal or family medullary thyroid cancer or MEN2.
  • pregnant: Stop weight-loss use when pregnancy is recognized; diabetes or MASH needs a separate clinician benefit-risk decision.
  • tryingToConceive: Stop at least 2 months before planned pregnancy because the drug clears slowly.
  • breastfeeding: Oral labels advise against breastfeeding; eight injection users cannot establish infant safety.
  • under18: Wegovy injection is also approved for selected ages 12+; this is not a universal pediatric drug contraindication.
  • eatingDisorderHistory: Assess nutrition and specialist support.
  • other: Do not use after serious allergy to semaglutide or product ingredients.
  • pancreatitisHistory: Past pancreatitis needs review. Stop and assess immediately if pancreatitis is suspected.
  • gallbladderDisease: Gallstones and gallbladder inflammation can occur, including during rapid weight loss.
  • gastroparesis: US labels do not recommend use with severe gastroparesis; review persistent vomiting or very slow stomach emptying.
  • diabeticRetinopathy: Rapid glucose improvement can worsen existing diabetic eye disease; arrange eye monitoring.
  • kidneyDisease: Dehydration can injure kidneys. US labels do not require routine renal dose adjustment; EU Wegovy restricts severe impairment.
  • liverDisease: US labels do not require routine liver dose adjustment. Cirrhosis is outside the approved MASH population.
  • heartCondition: Resting heart rate can rise; assess persistent racing, fainting or severe dizziness.
  • diabetes: Review glucose medicines and eye history; semaglutide does not replace required insulin.
  • surgeryPlanned: Slow stomach emptying can cause aspiration under anesthesia. Tell the team the formulation, dose and last dose date.
  • other: Prior NAION needs eye-specialist review; new vision loss needs urgent care. Stop semaglutide if NAION is confirmed.
  • depressionOrSuicidalThoughts: Seek help for new suicidal thoughts. FDA found no increased drug-related risk and requested warning removal January 13, 2026.
  • testedAthlete: WADA monitors semaglutide markers in and out of competition in 2026; monitoring is not prohibition.

Interactions

  • Insulin: Raises low-sugar risk. Insulin changes need glucose-guided adjustment; do not abruptly stop required insulin.
  • Sulfonylureas and insulin releasers: These medicines release insulin and can cause low blood sugar with semaglutide.
  • Other semaglutide or GLP-1 medicines: Avoid duplicate GLP-1 activity. Wegovy label does not recommend other semaglutide or GLP-1 medicines.
  • Levothyroxine: Oral semaglutide increased thyroxine exposure by 33% in a PK study; review timing and thyroid tests.
  • Warfarin and coumarins: No important warfarin PK change shown; EU guidance recommends frequent INR checks when starting semaglutide.
  • Oral medicines needing close monitoring: Slower stomach emptying may alter absorption. Review drug levels where used; an interaction is not established for every listed drug.
  • Oral contraceptives: Tested contraceptive exposure was not reduced. Vomiting or severe diarrhea still needs the pill’s missed-dose advice.
  • Other morning tablets with oral semaglutide: Take oral semaglutide first; wait ≥30 minutes before other oral medicines. These tested drugs showed no major PK effect.

Product quality risks

  • A 2024 test-purchase study received 3 of 6 online orders. Tested products had 7–14% purity and 29–39% more semaglutide than claimed.
  • One sample had elevated endotoxin; no viable microbes were found. A small negative sterility sample does not establish safe production.
  • FDA found counterfeit Ozempic in the legitimate US supply chain; authentic lot numbers alone do not prove authenticity.
  • FDA reports compounded-vial mistakes of 5–20 times the intended dose. Milligrams, milliliters and syringe units differ.
  • Semaglutide sodium and acetate differ from approved semaglutide; FDA does not know that they have the same properties.

How Semaglutide works

It copies a gut hormone that helps the brain feel full. It helps the pancreas release insulin when blood sugar is high and reduces glucagon. It slows stomach emptying, especially early in use. It does not activate GIP or glucagon receptors.

  • GLP-1 receptor: Increases fullness and glucose-dependent insulin release; reduces glucagon and can slow stomach emptying.

Half-life: About 1 week; circulating drug can persist about 5–7 weeks after the last dose.

Gaps: Community prevalence is unmeasured. Commonness reflects sampled threads; no systematic mention count was made. No controlled evidence found for the reported split dosing, low-dose obesity maintenance, longer gaps or cycling schedules. No trial validates semaglutide plus tirzepatide or independently sourced DIY CagriSema. Weekly 16 mg evidence includes one small trial; actual delivered ceiling was 16.13 mg, not an approved maximum. Human-study count means ClinicalTrials.gov intervention records, including ongoing and comparator studies. Some accessible reports give only adjusted differences. Unextracted arm rates and early-dose details are listed in notes. OASIS 3 was completed with no posted results or matched paper found. Oral 50 mg is EU-labeled for diabetes, but not FDA-approved. Rare eye injury, very long-term thyroid-cancer risk, and pregnancy or lactation safety remain uncertain. No final 503B exclusion or semaglutide-specific PCAC approval was identified by October 18, 2026. No reliable storage life found for home-mixed powder; approved pen storage periods do not transfer. EMA oral and US oral formulations have different dose ladders. Calendar-day or month text overrides approximate week bins.

Related to Semaglutide

Semaglutide: the short version

Sources

Sources checked: 2026-10-18.

Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.