Comparison
Semaglutide vs Vitamin D3 + K2
Side-by-side of Semaglutide and Vitamin D3 + K2. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Semaglutide
Semaglutide for weight loss: GLP-1 agonist (Ozempic, Wegovy) drives 15-17% mean loss at 2.4 mg/week in STEP trials. Watch lean-mass loss.
Vitamin D3 + K2
Vitamin D3 K2 supplement profile: cholecalciferol at 1000-4000 IU/day corrects deficiency, MK-7 directs calcium to bone, away from arteries.
Effects at a glance
Semaglutide
- •Long-acting GLP-1 receptor agonist with a ~7-day half-life that supports once-weekly subcutaneous dosing
- •STEP trials reported ~15 to 17% mean body-weight loss at 2.4 mg/week over 68 weeks in adults with obesity
- •Lowers HbA1c by ~1.0 to 1.8 percentage points in type 2 diabetes versus placebo
- •SELECT trial showed reduced major cardiovascular events in adults with prior CVD and overweight or obesity
- •Up to 25 to 40% of weight lost can be lean mass; pairing with resistance training and protein intake mitigates this
- •GI effects (nausea, vomiting, constipation) drive most discontinuations and ease with slow titration
Vitamin D3 + K2
- •Reduces non-vertebral fractures 10-20% in older adults at 800 IU/day or above when combined with calcium
- •VITAL trial showed neutral results on primary CV and cancer endpoints at 2000 IU/day over 5 years
- •Vitamin D supplementation reduces respiratory infection incidence ~10-20% in deficient populations
- •K2 MK-7 has 72-hour plasma half-life vs 1-2 hours for MK-4; once-daily dosing is sufficient
- •Synergy hypothesis is largely preclinical; dedicated combination RCTs are limited
- •Daily dosing outperforms bolus dosing for immune and infection outcomes
Side-by-side
| Attribute | Semaglutide | Vitamin D3 + K2 |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Ozempic, Wegovy, Rybelsus | cholecalciferol + menaquinone, D3/K2, vitamin D3 with MK-7 |
| Half-life (hr) ↗ | 168 | 360 |
| Typical dose (mg) ↗ | 2.4 | 0.05 |
| Dosing frequency | weekly (SC); daily (oral Rybelsus) | daily with a fat-containing meal |
| Routes | subcutaneous, oral | oral |
| Onset (hr) | 24 | 24 |
| Peak (hr) | 72 | 168 |
| Molecular weight | 4113.58 | 384.64 |
| Molecular formula | - | C27H44O (D3); C46H64O2 (MK-7) |
| Mechanism | Long-acting GLP-1 receptor agonist; potentiates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic satiety centers. | D3 converts to calcidiol then calcitriol, activating the vitamin D receptor (VDR) to increase intestinal calcium absorption and modulate immune and bone gene transcription. K2 carboxylates osteocalcin and matrix Gla protein, directing calcium toward bone and inhibiting vascular calcification. |
| Legal status | Prescription only (FDA-approved, EMA-approved) | Dietary supplement (global) |
| WADA status | allowed | allowed |
| DEA / Rx | Rx only (not a controlled substance); FDA-approved for type 2 diabetes (2017) and chronic weight management (2021) | Not scheduled |
| Pregnancy | Not recommended; discontinue 2 months before planned pregnancy | Recommended at standard doses for fetal bone development; consult clinician at higher doses |
| CAS | 910463-68-2 | 67-97-0 |
| PubChem CID | 56843331 | 5280795 |
| Wikidata | Q27089394 | Q139347 |
Safety profile
Semaglutide
Common side effects
- nausea
- vomiting
- diarrhea
- constipation
- decreased appetite
- injection-site reactions
- fatigue
Contraindications
- personal or family history of medullary thyroid carcinoma
- multiple endocrine neoplasia type 2
- pregnancy
- history of pancreatitis (use caution)
Interactions
- insulin: additive hypoglycemia risk; insulin dose typically reduced(major)
- sulfonylureas (glipizide, glyburide): hypoglycemia risk, sulfonylurea dose often reduced(major)
- oral medications (general): delayed gastric emptying can alter absorption kinetics(moderate)
- warfarin: monitor INR due to altered absorption(moderate)
Vitamin D3 + K2
Common side effects
- GI upset at high doses
- headache (rare)
- hypercalcemia (only at sustained very high D3 doses)
Contraindications
- hypercalcemia
- sarcoidosis
- active hyperparathyroidism
- warfarin therapy (K2 component requires stable intake)
Interactions
- warfarin: K2 component can affect anticoagulation; maintain stable intake and inform anticoagulation clinic(moderate)
- thiazide diuretics: additive calcium retention; hypercalcemia risk with high-dose D3(moderate)
- digoxin and calcium channel blockers: additive effects from D3-induced hypercalcemia(moderate)
- glucocorticoids: reduced vitamin D efficacy and bone effects(moderate)
- cholestyramine and orlistat: bind fat-soluble vitamins; separate dosing by 2 to 4 hours(moderate)
Which Should You Take?
Vitamin D3 + K2 comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. Semaglutide is the right call when one of the conditionals below applies.
- → If your priority is metabolic health and glucose control, pick Semaglutide.
- → If your priority is fat loss, pick Semaglutide.
- → If your priority is bone density, pick Vitamin D3 + K2.
- → If your priority is healthspan extension, pick Vitamin D3 + K2.
Edge case: If you want to avoid prescription-only, Vitamin D3 + K2 is the more accessible choice.
Default choice: Vitamin D3 + K2. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Semaglutide only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Semaglutide and Vitamin D3 + K2?
Semaglutide and Vitamin D3 + K2 differ in category (pharmaceutical vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Semaglutide or Vitamin D3 + K2?
Semaglutide half-life is 168 hours; Vitamin D3 + K2 half-life is 360 hours.
Can you stack Semaglutide with Vitamin D3 + K2?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper