Question 1

What is the starting dose of semaglutide?

Accepted Answer

The FDA-approved starting dose for weight management (Wegovy) is 0.25 mg once weekly by subcutaneous injection. This dose is for tolerability only and is not considered therapeutic. After 4 weeks at 0.25 mg, the dose increases to 0.5 mg weekly, then steps up every 4 weeks through 1.0 mg and 1.7 mg until reaching the 2.4 mg maintenance dose by about week 17. For type 2 diabetes (Ozempic), the same 0.25 mg starting dose applies, but the maximum dose is 2.0 mg weekly.

Question 2

What is semaglutide's half-life?

Accepted Answer

Semaglutide has a half-life of about 7 days (165-184 hours), among the longest for current GLP-1 receptor agonists. A fatty acid chain attached to the peptide binds to albumin in the blood, which slows clearance. The 7-day half-life supports once-weekly dosing and means it takes about 4-5 weeks at each dose level to reach steady state. After stopping, semaglutide remains in the body for roughly 5-7 weeks.

Question 3

How much weight can you lose on semaglutide?

Accepted Answer

In the STEP 1 clinical trial (NEJM, 2021), participants on semaglutide 2.4 mg lost an average of 14.9% of body weight at 68 weeks (about 33.6 lbs from a 232 lb average baseline) vs 2.4% with placebo. 86.4% achieved at least 5% loss, and about one-third reached 20% or more. STEP 3 with intensive behavior therapy showed 16.0% loss. STEP 5 showed sustained 15.2% loss at 2 years. STEP 2 in type 2 diabetes showed 9.6% loss.

Question 4

How do you reconstitute semaglutide?

Accepted Answer

Reconstitution applies to lyophilized (freeze-dried) research-grade semaglutide. Brand Ozempic and Wegovy pens come pre-filled and skip this step. A common setup is a 5 mg vial with 2.0 mL bacteriostatic water, which yields a 2.5 mg/mL concentration where 0.25 mg equals 10 units on a U-100 syringe. Inject water slowly down the vial wall, swirl gently (do not shake), and refrigerate at 2-8C. Use within 28 days. For custom math, use the Pep Pal calculator .

Question 5

Is semaglutide FDA-approved?

Accepted Answer

Yes. As of June 2026, semaglutide has broad FDA approval across multiple indications and brand names. Ozempic is approved for type 2 diabetes glycemic control (2017), cardiovascular risk reduction in T2D (2020), and CKD progression in T2D (February 2026). Wegovy is approved for chronic weight management (2021), cardiovascular risk reduction in adults with obesity and CVD (2024), and non-cirrhotic MASH with F2-F3 fibrosis (August 2025). The oral Wegovy 25 mg pill was approved in December 2025. Rybelsus is the older oral T2D form.

Question 6

What are the most common observed effects?

Accepted Answer

Stomach observed effects are most common. In pooled STEP 1-3 data on the 2.4 mg dose, nausea occurred in 43.9% (vs 16.1% placebo), diarrhea in 29.7% (vs 15.9%), vomiting in 24.5% (vs 6.3%), and constipation in 24.2% (vs 11.1%). These were most frequent during dose escalation, peaked around weeks 8-20, and were usually mild-to-moderate and transient. Permanent discontinuation due to observed effects was 6.8%. Semaglutide carries a boxed warning for thyroid C-cell tumors in rodent studies and is contraindicated in people with MTC or MEN 2.

Question 7

How does semaglutide compare to tirzepatide and retatrutide?

Accepted Answer

Semaglutide is a single GLP-1 receptor agonist. Tirzepatide is a dual GLP-1 + GIP agonist. Retatrutide is a triple GLP-1 + GIP + glucagon agonist. In SURMOUNT-5 head-to-head, tirzepatide 15 mg produced -20.2% weight loss vs -13.7% for semaglutide 2.4 mg at 72 weeks. Retatrutide Phase 3 reported up to -28.7% at 68 weeks. Semaglutide's strength is depth of outcomes evidence: SELECT cardiovascular data, FLOW kidney protection, MASH approval (ESSENCE), and oral formulations.

Question 8

What vial sizes are available for research semaglutide?

Accepted Answer

Lyophilized semaglutide is commonly offered by research suppliers in 2 mg, 3 mg, 5 mg, and 10 mg vials. The 5 mg vial is the most common pick because it supports multiple weeks at typical doses and pairs cleanly with 2.0 mL bacteriostatic water for a 2.5 mg/mL mix. The 10 mg vial can be more cost-effective for higher-dose or longer protocols. Vial size and water volume should be chosen together, because they drive the syringe-unit math.

Question 9

How much bacteriostatic water should be added to semaglutide?

Accepted Answer

BAC water volume depends on vial size and desired concentration. For a 5 mg vial, 2.0 mL gives 2.5 mg/mL, where 0.25 mg = 10 units and 2.4 mg = 96 units on a U-100 syringe. For a 10 mg vial, 3.0 mL gives about 3.33 mg/mL, where 0.25 mg = 7.5 units and 2.4 mg = 72 units. A more concentrated 5 mg/mL option (5 mg in 1.0 mL) gives smaller draws but needs more precise syringe handling. Use the Pep Pal calculator for any custom setup.

Question 10

What is the maximum dose of semaglutide studied?

Accepted Answer

The maximum FDA-approved subcutaneous dose is 2.4 mg weekly (Wegovy) for weight management. For type 2 diabetes (Ozempic), the maximum approved dose is 2.0 mg weekly. The oral maximum is 25 mg daily (Wegovy 25 mg pill, approved December 2025) or 14 mg daily (Rybelsus). In SELECT, the 2.4 mg dose produced a 20% reduction in major cardiovascular events. Published Phase 3 programs have not established higher subcutaneous maintenance doses than 2.4 mg weekly.

Question 11

How should reconstituted semaglutide be stored?

Accepted Answer

Reconstituted semaglutide should be refrigerated at 2-8C (35.6-46.4F) and used within 28 days. Do not freeze reconstituted semaglutide - freezing can degrade the peptide. Protect from light and label vials with the reconstitution date and concentration. Brand-name pens follow their own label rules: unused pens stay refrigerated, and after first use, pens can be stored at room temperature (up to 86F/30C) or refrigerated for up to 56 days.

Question 12

Is Wegovy 25 mg the same as Rybelsus?

Accepted Answer

No. Both are oral semaglutide, but they are different products with different maximum doses and approved indications. Rybelsus tops out at 14 mg daily and is approved for type 2 diabetes. The Wegovy 25 mg pill was approved in December 2025 for chronic weight management and tops out at 25 mg daily. Both must be taken on an empty stomach with a small sip of water, with no food, drink, or other medication for 30 minutes after.

Question 13

Is semaglutide insulin?

Accepted Answer

No. Semaglutide is not insulin. It is a GLP-1 receptor agonist - a drug that copies the natural gut hormone GLP-1. It does cause the pancreas to release insulin, but only when blood sugar is already high (glucose-dependent insulin secretion). That is why semaglutide is much less likely to cause dangerous low blood sugar than direct insulin. Insulin works by directly adding the hormone insulin to the body. Semaglutide works by signaling the body to release its own insulin when it is needed.

Question 14

Is there a generic semaglutide?

Accepted Answer

As of June 2026, no generic semaglutide is FDA-approved in the United States. Novo Nordisk still holds active patents. The FDA-recognized shortage of semaglutide ended in 2025, which narrowed the legal scope of 503A/503B compounded semaglutide. Some countries have different patent timelines, with generic semaglutide expected in Canada earlier than the US. Verify current status with FDA orange-book listings and country-specific regulators before relying on this answer.

Question 15

Where can I calculate reconstitution and syringe units?

Accepted Answer

Use the Pep Pal calculator for exact dose-to-unit conversions. Enter vial size, BAC water volume, and target dose to get the matching syringe draw.

Question 16

Where can I compare peptide suppliers?

Accepted Answer

Browse the PepPal supplier directory for current supplier listings, or read the PepPal supplier rankings for ranked comparisons with Finnrick testing context.

Phase	Reference amount	Units / volume
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)

Phase	5 mg 2 mL water	10 mg 3 mL water	20 mg 3 mL water
Weeks 1–4	10 u 0.10 mL	7.5 u 0.07 mL	4 u 0.04 mL
Weeks 5–8	20 u 0.20 mL	15 u 0.15 mL	7.5 u 0.07 mL
Weeks 9–12	40 u 0.40 mL	30 u 0.30 mL	15 u 0.15 mL
Weeks 13–16	68 u 0.68 mL	51 u 0.51 mL	25.5 u 0.26 mL
Weeks 17+ (Maintenance)	96 u 0.96 mL	72 u 0.72 mL	36 u 0.36 mL

Semaglutide.

Calculated volume reference

Cited protocol & reconstitution guide

Reconstitution by vial size