Semaglutide
Semaglutide is a GLP-1 receptor agonist — a 31-amino acid peptide analog of human glucagon-like peptide-1 (GLP-1) with a 94% sequence homology to native GLP-1. It is FDA-approved for type 2 diabetes (Ozempic, Rybelsus) and chronic weight management (Wegovy). Semaglutide has an albumin-binding fatty acid side chain that extends its half-life to approximately 7 days, enabling once-weekly dosing. It is the most widely prescribed GLP-1 medication globally, with over 25 million Americans expected to be on GLP-1 therapy by 2030.
Mechanism of Action
Semaglutide binds to and activates the GLP-1 receptor, a G-protein coupled receptor expressed in pancreatic beta cells, the hypothalamus, and the gastrointestinal tract. This triggers multiple downstream effects: (1) glucose-dependent insulin secretion from pancreatic beta cells, (2) suppression of glucagon release from alpha cells, (3) delayed gastric emptying, slowing nutrient absorption, (4) central appetite suppression via hypothalamic GLP-1 receptors, reducing hunger and increasing satiety. The peptide features a C-18 fatty diacid moiety attached via a linker to Lys26, enabling non-covalent albumin binding that protects against DPP-4 degradation and renal clearance.
Dosage Overview
Dose Range
250 mcg – 2.4 mg
Route
subcutaneous or oral
Frequency
Weekly
Cycle Length
16–52 weeks
Typical Dosage (Research)
For weight management (Wegovy): start at 0.25 mg weekly for 4 weeks, escalate to 0.5 mg, 1.0 mg, 1.7 mg, and finally 2.4 mg weekly. Each escalation lasts 4 weeks. Maintenance dose is 2.4 mg weekly. For type 2 diabetes (Ozempic): start at 0.25 mg weekly for 4 weeks, increase to 0.5 mg. May increase to 1 mg, then 2 mg if additional glycemic control is needed. Oral semaglutide (Rybelsus): 3 mg daily for 30 days, then 7 mg daily. May increase to 14 mg daily. Oral Wegovy: 3 mg daily for 4 weeks, escalate to 7 mg, 14 mg, and 25 mg daily. Take on empty stomach with no more than 4 oz of water, 30 minutes before food.
Injectable: subcutaneous injection in the abdomen, thigh, or upper arm. Rotate injection sites. Store pens refrigerated (36-46°F) before first use; after first use, store at room temperature or refrigerated for up to 56 days. Oral: take on an empty stomach with a sip of plain water (no more than 4 oz). Wait at least 30 minutes before eating, drinking, or taking other oral medications. Do not split, crush, or chew tablets.
Considerations for Men & Women
Clinical trials show similar efficacy in males and females, though females report higher rates of GI side effects (particularly nausea). Hair loss (telogen effluvium) appears more commonly reported in females. Contraindicated in pregnancy — discontinue at least 2 months before planned conception due to long half-life.
Individual responses vary. These notes reflect general trends from research literature and are not medical advice.
Dose Escalation Calculator
NOT Medical Advice
The dosage and calculator information provided is for educational and research purposes only. Peptides are not approved by the FDA for human use. Individual responses vary significantly. Always consult with a qualified healthcare professional before making any decisions related to peptide research or use.
Wegovy Dose Escalation
When did you take your first dose?
For cost projection over the escalation period
Escalation Schedule
Weeks 1–4
Month 1
Weeks 5–8
Month 2
Weeks 9–12
Month 3
Weeks 13–16
Month 4
Week 17+
Maintenance
Each dose level lasts 4 weeks. Do not increase dose faster than the schedule. If you cannot tolerate a dose, your provider may delay escalation.
Side Effects & Risks
Very common (>10%): nausea (up to 44%), diarrhea, vomiting, constipation, abdominal pain. These are typically mild-to-moderate and decrease over time with dose escalation. Common (1-10%): headache, fatigue, dyspepsia, dizziness, bloating, flatulence, GERD, gastroenteritis. Notable: 'Ozempic face' (facial volume loss due to rapid weight loss), hair loss (telogen effluvium, reported in 25-33% of users in some studies), injection site reactions.
Black box warning: thyroid C-cell tumors observed in rodent studies. Contraindicated in patients with personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Risk of pancreatitis — discontinue if suspected. Potential for gallbladder-related events (cholelithiasis, cholecystitis). Risk of hypoglycemia when combined with insulin or sulfonylureas. Muscle loss: 20-40% of weight lost may be lean mass. Suicidal ideation reports are under FDA review. Not recommended in pregnancy.
Who Uses Semaglutide
Adults with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related comorbidity, seeking medically supervised weight loss. Adults with type 2 diabetes for glycemic control. Increasingly used for cardiovascular risk reduction (SELECT trial showed 20% MACE reduction).
Frequently Asked Questions
Similar Peptides
View All Alternatives →Liraglutide is a GLP-1 receptor agonist — a 31-amino acid peptide analog with 97% homology to native human GLP-1. FDA-approved for type 2 diabetes (Victoza, 2010) and chronic weight management (Saxenda, 2014). It was the first GLP-1 agonist approved specifically for obesity. Liraglutide has a shorter half-life than semaglutide (13 hours vs 7 days), requiring daily rather than weekly dosing.
Orforglipron (LY3502970) is a non-peptide, oral GLP-1 receptor agonist developed by Eli Lilly. Unlike oral semaglutide (which is a peptide requiring special formulation), orforglipron is a small molecule — the first of a new class of oral GLP-1 drugs that can be taken without fasting restrictions. It is in Phase 3 trials for obesity and type 2 diabetes, with an FDA decision expected in 2026. Projected to reach $16 billion in annual sales by 2031.
Tirzepatide is the first dual GIP/GLP-1 receptor agonist — a 39-amino acid synthetic peptide that activates both the glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors. FDA-approved for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound). In clinical trials, tirzepatide demonstrated greater weight loss than semaglutide, with up to 22.5% body weight reduction at the highest dose.
Retatrutide (LY3437943) is a first-in-class triple agonist peptide targeting GIP, GLP-1, and glucagon receptors simultaneously. Developed by Eli Lilly, it is currently in Phase 3 clinical trials and has demonstrated the highest weight loss of any obesity medication to date — up to 28.7% body weight reduction at 48 weeks. The triple-receptor mechanism represents the next evolution beyond dual agonists like tirzepatide.
CagriSema is a fixed-ratio combination of cagrilintide (a long-acting amylin analog) and semaglutide, developed by Novo Nordisk. By combining two distinct appetite-regulating peptide hormones, CagriSema aims to achieve greater weight loss than semaglutide alone. Phase 3 data showed 22.7% body weight reduction, and an FDA response is expected in 2026.