Semaglutide is a long-acting GLP-1 receptor agonist studied extensively for glycemic control and chronic weight management. Unlike many peptides discussed on ResearchDosing-style sites, semaglutide has substantial randomized trial evidence and multiple regulatory approvals depending on indication and brand/formulation.
— 5 mg Vial —
Reconstitute: Add 2.0 mL bacteriostatic water → ~2.5 mg/mL concentration.
Weekly dose range: 250–2400 mcg (0.25–2.4 mg) once weekly (gradual escalation protocol).
Easy measuring: At 2.5 mg/mL, 1 unit = 0.01 mL ≈ 25 mcg on a U-100 insulin syringe.
Storage: Lyophilized: freeze at −20 °C; reconstituted: refrigerate at 2–8 °C, use within 28 days.
Schedule: Weekly subcutaneous injections for 16–20+ weeks with gradual dose escalation.
Goal: Support chronic weight management through GLP-1 receptor activation, leading to reduced appetite and improved metabolic parameters.
Frequency: Inject once weekly subcutaneously. This gradual titration protocol improves tolerability. Administer on the same day each week at any time, with or without meals.
| Phase | Dose | Syringe (U-100) |
|---|---|---|
| Weeks 1–4 | 250 mcg (0.25 mg) | 10 units (0.10 mL) |
| Weeks 5–8 | 500 mcg (0.5 mg) | 20 units (0.20 mL) |
| Weeks 9–12 | 1000 mcg (1.0 mg) | 40 units (0.40 mL) |
| Weeks 13–16 | 1700 mcg (1.7 mg) | 68 units (0.68 mL) |
| Weeks 17+ (Maintenance) | 2400 mcg (2.4 mg) | 96 units (0.96 mL) |
— 10 mg Vial —
Reconstitute: Add 3.0 mL bacteriostatic water → ~3.33 mg/mL concentration.
Weekly dose range: 250–2400 mcg (0.25–2.4 mg) once weekly (gradual escalation protocol).
Easy measuring: At 3.33 mg/mL, 1 unit = 0.01 mL ≈ 33.3 mcg on a U-100 insulin syringe.
Storage: Lyophilized: freeze at −20 °C; reconstituted: refrigerate at 2–8 °C, use within 28 days.
Schedule: Weekly subcutaneous injections for 16–20+ weeks with gradual dose escalation.
Goal: Support chronic weight management through GLP-1 receptor activation.
Frequency: Inject once weekly subcutaneously. Administer on the same day each week at any time, with or without meals.
| Phase | Dose | Syringe (U-100) |
|---|---|---|
| Weeks 1–4 | 250 mcg (0.25 mg) | 7.5 units (0.075 mL) |
| Weeks 5–8 | 500 mcg (0.5 mg) | 15 units (0.15 mL) |
| Weeks 9–12 | 1000 mcg (1.0 mg) | 30 units (0.30 mL) |
| Weeks 13–16 | 1700 mcg (1.7 mg) | 51 units (0.51 mL) |
| Weeks 17+ (Maintenance) | 2400 mcg (2.4 mg) | 72 units (0.72 mL) |
— 20 mg Vial —
Reconstitute: Add 3.0 mL bacteriostatic water → ~6.67 mg/mL concentration.
Weekly dose range: 250–2400 mcg (0.25–2.4 mg) once weekly (gradual escalation protocol).
Easy measuring: At 6.67 mg/mL, 1 unit = 0.01 mL ≈ 66.7 mcg on a U-100 insulin syringe.
Storage: Lyophilized: freeze at −20 °C; reconstituted: refrigerate at 2–8 °C, use within 28 days.
Schedule: Weekly subcutaneous injections for 16–20+ weeks with gradual dose escalation.
Goal: Support chronic weight management through GLP-1 receptor activation.
Frequency: Inject once weekly subcutaneously. Administer on the same day each week at any time, with or without meals.
| Phase | Dose | Syringe (U-100) |
|---|---|---|
| Weeks 1–4 | 250 mcg (0.25 mg) | 4 units (0.04 mL) |
| Weeks 5–8 | 500 mcg (0.5 mg) | 7.5 units (0.075 mL) |
| Weeks 9–12 | 1000 mcg (1.0 mg) | 15 units (0.15 mL) |
| Weeks 13–16 | 1700 mcg (1.7 mg) | 25.5 units (0.255 mL) |
| Weeks 17+ (Maintenance) | 2400 mcg (2.4 mg) | 36 units (0.36 mL) |
Semaglutide is a GLP-1 analog engineered for prolonged half-life (once-weekly dosing for injectable formulations) through amino acid substitutions and albumin-binding via a fatty-acid side chain. It has been studied for type 2 diabetes, obesity, and cardiovascular risk reduction in specific populations.
- Weight loss: clinically meaningful mean weight reduction in STEP trials.
- Appetite reduction: increased satiety and reduced energy intake (GLP-1 physiology).
- Glycemic control: lowers A1c and fasting glucose in T2D programs (SUSTAIN).
- Cardiovascular outcomes: reduced major adverse cardiovascular events in high-risk T2D (SUSTAIN-6) and overweight/obesity with established CVD (SELECT).
- Metabolic risk markers: improvements in waist circumference, BP, and some lipid parameters in trials.
Semaglutide activates the GLP-1 receptor, leading to glucose-dependent insulin secretion, reduced glucagon secretion, delayed gastric emptying, and central appetite regulation. Appetite effects involve hypothalamic and brainstem signaling; in gut–brain axis terms, GLP-1 is a key incretin connecting nutrient sensing in the gut with satiety signaling in the CNS.
- GI: nausea, vomiting, diarrhea, constipation (most common; dose-related).
- Decreased appetite (expected pharmacology).
- Reflux / dyspepsia in some users.
- Gallbladder disease risk may increase with rapid weight loss.
- Hypoglycemia mainly when combined with insulin or sulfonylureas.
- Personal or family history of medullary thyroid carcinoma (MTC) or MEN2 (boxed warning for GLP-1 RAs).
- History of severe hypersensitivity to semaglutide.
- Pancreatitis: discontinue if suspected; use caution with history.
- Gastroparesis: may worsen due to gastric-emptying effects.
- Pregnancy: generally discontinue for planned conception (follow product labeling/clinician guidance).
Commercial semaglutide injection products are intended for subcutaneous (SubQ) administration. Intramuscular (IM) use is not standard and is not recommended.
Semaglutide has FDA-approved products for type 2 diabetes (including once-weekly injectable and oral tablet formulations) and for chronic weight management (higher-dose once-weekly injectable). Indications, dosing ceilings, and eligibility criteria differ by brand and labeling.
FDA-approved semaglutide injection pens are supplied as ready-to-use solutions and do not require reconstitution. If you are handling non-commercial semaglutide powder in a laboratory, follow institution SOPs; sterility and concentration accuracy are critical and cannot be assumed for gray-market materials.
- Resistance training + protein-forward nutrition: commonly used to preserve lean mass during weight loss.
- Metformin (T2D): frequently co-prescribed; monitor GI tolerance.
- Do not casually stack with other appetite suppressants or multiple incretin drugs without clinician oversight.
- Once-weekly semaglutide in type 2 diabetes (SUSTAIN-6 CV outcomes). N Engl J Med. 2016. PMID: 27633186
- Semaglutide for obesity (STEP 1). N Engl J Med. 2021. PMID: 33567185
- Semaglutide for obesity in T2D (STEP 2). Lancet. 2021. PMID: 33667417
- Semaglutide in adolescents with obesity (STEP TEENS). N Engl J Med. 2022. PMID: 36322838
- Oral semaglutide in type 2 diabetes (PIONEER 1). JAMA. 2019. PMID: 31135820
- Semaglutide and cardiovascular outcomes in obesity with established CVD (SELECT). N Engl J Med. 2023. PMID: 37952131
- GLP-1 physiology / incretin signaling overview relevant to gut–brain satiety. Physiol Rev. 2007. PMID: 17615389
- Mechanistic discussion of GLP-1 and appetite/energy intake. Nat Rev Endocrinol. 2012. PMID: 22945300