Semaglutide / Cyanocobalamin Injection — GLP-1 + Vitamin B12

Route: Subcutaneous injection, once weekly.

• Inject into the abdomen (below the navel), thigh, or upper arm. Rotate sites with each weekly injection.
• Administer on the same day each week, with or without food, at any time of day.
• Using a fine-gauge insulin syringe: draw the prescribed volume from the vial, remove air bubbles, pinch the skin, and inject at a 45–90° angle into subcutaneous tissue.
• Apply gentle pressure after injection; do not rub the site.
• Dispose of needles and syringes in an approved sharps container.

All dosing is prescriber-determined. Semaglutide is titrated gradually to minimize GI adverse effects. A standard weight-management titration reference (based on FDA-approved Wegovy protocol):

• Weeks 1–4: 0.25 mg once weekly
• Weeks 5–8: 0.5 mg once weekly
• Weeks 9–12: 1.0 mg once weekly
• Weeks 13–16: 1.7 mg once weekly
• Week 17 onward: 2.4 mg once weekly (maintenance for obesity)
• For T2DM glycemic control, lower maintenance doses (0.5–2.0 mg weekly) are used per Ozempic labeling.
• Cyanocobalamin dosing is prescriber-specified; standard supplemental B12 injection doses range from 100–1000 mcg.
• Do not change dose or schedule without prescriber direction.

• Semaglutide: A GLP-1 analog with 94% structural homology to human GLP-1; binds GLP-1 receptors on pancreatic β-cells (stimulating glucose-dependent insulin secretion), α-cells (suppressing glucagon), gastrointestinal tract (slowing gastric emptying), and hypothalamic neurons (suppressing appetite and food intake via arcuate nucleus signaling). Two structural modifications (C18 fatty acid chain enabling albumin binding, and a substitution at position 8 conferring DPP-4 resistance) extend its half-life to approximately 1 week, enabling once-weekly subcutaneous dosing.
• Cyanocobalamin: Converted in vivo to the active coenzyme forms methylcobalamin and adenosylcobalamin. Methylcobalamin is required for methionine synthase (homocysteine → methionine; folate cycle) and adenosylcobalamin for methylmalonyl-CoA mutase (propionate metabolism). Deficiency causes megaloblastic anemia and subacute combined degeneration of the spinal cord. Supplementation prevents these sequelae in patients whose dietary intake is restricted.

Indication context: Semaglutide injection is FDA-approved under brand names Ozempic (type 2 diabetes, CV risk reduction) and Wegovy (chronic weight management, obesity or overweight with ≥1 weight-related comorbidity). Compounded semaglutide/cyanocobalamin is prescribed for patients requiring individualized dosing or additional B12 support as part of a comprehensive metabolic management plan.

Monitoring considerations:

• HbA1c and fasting glucose (for T2DM patients) at 3-month intervals.
• Body weight and BMI monthly for weight management.
• Renal function: mild eGFR changes observed in some patients; baseline and periodic monitoring in at-risk patients.
• Gastric emptying: semaglutide delays gastric emptying; counsel patients on pacing meals, eating slowly, and avoiding high-fat trigger foods.
• Pancreatic enzymes (amylase/lipase) if symptoms of pancreatitis occur.
• Thyroid (calcitonin) if medullary thyroid carcinoma risk factors are present; semaglutide carries a black-box warning for rodent thyroid C-cell tumors (human relevance uncertain).
• Vitamin B12 levels annually or if neurological symptoms develop.
• Ophthalmologic assessment if diabetic retinopathy progression is suspected.

Contraindications:

• Personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN 2).
• Known hypersensitivity to semaglutide or any component.
• History of serious hypersensitivity reaction (anaphylaxis, angioedema) to GLP-1 receptor agonists.

Warnings & Precautions:

• Black box warning: Risk of thyroid C-cell tumors observed in rodents; relevance to humans not established, but contraindicated in those with MTC/MEN2 history.
• Pancreatitis: discontinue if suspected; do not restart if pancreatitis is confirmed.
• Diabetic retinopathy complications: rapid improvement in glycemic control may worsen diabetic retinopathy acutely; monitor closely.
• Hypoglycemia: risk increased when co-administered with insulin or sulfonylureas; dose reduction of those agents may be required.
• GI adverse effects are most common during titration; dose escalation should be gradual.
• Heart rate increase: semaglutide may modestly increase resting HR; monitor in patients with cardiac disease.

Drug Interactions:

• Oral medications: delayed gastric emptying may reduce peak plasma concentrations of oral drugs taken concomitantly—take time-sensitive oral medications (e.g., oral contraceptives, antibiotics) at a consistent time relative to semaglutide injection.
• Insulin/sulfonylureas: increased hypoglycemia risk; monitor blood glucose.
• Warfarin: monitor INR due to GI motility effects on absorption.

Common Side Effects: Nausea (most common, especially during titration), vomiting, diarrhea, constipation, abdominal pain, dyspepsia; injection site reactions; less commonly—fatigue, headache, dizziness.

Store unopened vials refrigerated (2–8°C / 36–46°F). Protect from light. Do not freeze and do not use if previously frozen. Once opened (punctured), store in the refrigerator and use within the beyond-use date assigned by Genesis Compounding. Opened vials should not be used beyond 28 days (or the beyond-use date, whichever is earlier). Keep out of reach of children. Do not shake.

Why is B12 added to semaglutide?

Semaglutide-induced appetite reduction and dietary restriction can reduce dietary B12 intake. Additionally, GLP-1 receptor activity in the gut may affect intrinsic factor secretion and B12 absorption. Including cyanocobalamin in the injection ensures adequate B12 replacement to prevent neurological complications and megaloblastic anemia that can develop over months of restricted intake.

How do I inject this once-weekly medication?

Choose an injection site (abdomen, thigh, or upper arm), rotate sites each week. Draw the prescribed volume into an insulin syringe, remove air bubbles, pinch the skin, and inject subcutaneously. Apply gentle pressure afterward without rubbing. Dispose of needles immediately in a sharps container.

Is this the same as Ozempic or Wegovy?

Semaglutide is the active ingredient in Ozempic (diabetes) and Wegovy (weight management). This compounded preparation uses the same active pharmaceutical ingredient (semaglutide) prepared by Genesis Compounding with cyanocobalamin as a patient-specific 503A product. It is not FDA-approved as a compounded combination product.

What should I do if I experience severe nausea or vomiting?

Nausea is most common during dose escalation. Eat slowly, avoid large meals, and choose lower-fat foods. If nausea or vomiting is severe or prevents adequate oral intake, contact your prescriber—dose reduction or temporary hold may be appropriate. Seek care if you cannot keep fluids down.

Can semaglutide cause thyroid cancer?

Animal studies showed thyroid C-cell tumors at exposures much higher than clinical doses. The clinical relevance to humans is currently unknown. Semaglutide is contraindicated in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2. Routine calcitonin monitoring is not established as routine practice for all patients.