Comparison
CJC-1295 vs Vitamin D3 + K2
Side-by-side of CJC-1295 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.
CJC-1295
CJC-1295 peptide profile: GHRH analog forms (with-DAC ~7-day half-life, no-DAC Mod GRF 1-29 ~30 min), ipamorelin pairing, recovery use, dosing, side effects.
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
CJC-1295
- •GHRH analog that binds the GHRH receptor on pituitary somatotrophs to release endogenous GH
- •DAC variant has ~7 day half-life via albumin binding; non-DAC variant ~30 minutes
- •Teichman 2006 trial showed sustained 2 to 10 fold IGF-1 elevation at 60 to 250 mcg/kg DAC dosing
- •Anecdotal protocols pair non-DAC CJC-1295 with Ipamorelin to mimic pulsatile GH release
- •Side effects: water retention, numbness or tingling at injection site, vivid dreams, transient flushing
- •No completed phase III RCTs; research-use-only and not FDA approved
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 | CJC-1295 | Vitamin D3 + K2 |
|---|---|---|
| Category | peptide | supplement |
| Also known as | CJC-1295 DAC, CJC-1295 no-DAC, Mod GRF 1-29, tesamorelin analog | cholecalciferol + menaquinone, D3/K2, vitamin D3 with MK-7 |
| Half-life (hr) ↗ | 168 | 360 |
| Typical dose (mg) ↗ | 0.1 | 0.05 |
| Dosing frequency | weekly (DAC); 1-3x daily (non-DAC) | daily with a fat-containing meal |
| Routes | subcutaneous | oral |
| Onset (hr) | 1 | 24 |
| Peak (hr) | 3 | 168 |
| Molecular weight | 3367.83 | 384.64 |
| Molecular formula | C152H252N44O42 | C27H44O (D3); C46H64O2 (MK-7) |
| Mechanism | Binds the GHRH receptor on pituitary somatotrophs, stimulating pulsatile growth-hormone release. The DAC modification extends plasma residence by tethering the peptide to serum albumin via a maleimide-cysteine bond. | 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 | Not FDA approved; research-use-only grey market; banned by WADA | Dietary supplement (global) |
| WADA status | banned | allowed |
| DEA / Rx | Not FDA approved; not scheduled; research-chemical status | Not scheduled |
| Pregnancy | Insufficient data; not recommended | Recommended at standard doses for fetal bone development; consult clinician at higher doses |
| CAS | 446262-90-4 | 67-97-0 |
| PubChem CID | 91971820 | 5280795 |
| Wikidata | Q5012154 | Q139347 |
Safety profile
CJC-1295
Common side effects
- injection-site reactions
- water retention
- numbness or tingling at injection site
- vivid dreams
- transient flushing
- head pressure or mild headache
Contraindications
- pregnancy
- active malignancy
- diabetic retinopathy (theoretical)
- history of pituitary tumor
Interactions
- Ipamorelin: synergistic GH release; commonly co-administered in anecdotal protocols(minor)
- insulin: GH-induced insulin resistance can shift glycemic control over weeks(moderate)
- corticosteroids: blunt GH-axis response; reduce expected efficacy(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. CJC-1295 is the right call when one of the conditionals below applies.
- → If your priority is post-training recovery, pick CJC-1295.
- → If your priority is growth-hormone axis, pick CJC-1295.
- → 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 research-only / gray-market sourcing, 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 CJC-1295 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 CJC-1295 and Vitamin D3 + K2?
CJC-1295 and Vitamin D3 + K2 differ in category (peptide vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, CJC-1295 or Vitamin D3 + K2?
CJC-1295 half-life is 168 hours; Vitamin D3 + K2 half-life is 360 hours.
Can you stack CJC-1295 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