Cholecalciferol + Menaquinone · D3/K2 · Vitamin D + Vitamin K
Baseline hormone-axis support that amplifies GH secretagogue outcomes.
FDA
Approved
WADA
Not Listed
HALF-LIFE
~2–3 weeks (D3); days (K2 MK-7)
ROUTE
Oral
SCHEDULE
Daily
In Plain English
Baseline hormone-axis support that amplifies GH secretagogue outcomes.
Status & Legality
NATTY?
No Test ExistsNo established test exists for this compound.
FDA
ApprovedFDA approved for human use.
WADA
Not ListedNot currently on WADA prohibited list.
COMPOUNDING
Rx AvailableAvailable at licensed pharmacies with prescription.
PRESCRIBED
By prescriptionPhysicians can prescribe this compound legally.
ROUTE
OralAdministration via oral.
Hormone axis support
Calcium metabolism
Immune modulation
GH secretagogue adjunct
Vitamin D3 acts as a steroid hormone precursor, regulating over 1,000 genes including those involved in testosterone and GH signaling. K2 (MK-7) directs calcium deposited by D3 into bone rather than soft tissue. Most people running peptide protocols — especially GH secretagogues — are D-deficient without knowing it, which blunts the hormone-axis response. Testing and optimizing is a high-leverage, low-cost intervention.
Hypercalcemia only at very high doses (>50,000 IU long-term)
Nausea at doses >10,000 IU without food
K2 interaction with warfarin — caution
Excellent safety at recommended doses
Taking D3 without K2 long-term — D3 increases calcium absorption; K2 (MK-7) directs it into bone rather than soft tissue; the K2 is not optional
Not testing 25(OH)D before supplementing — baseline levels vary widely; some need 2,000 IU, others need 10,000 IU to reach optimal range (50–80 ng/mL)
Supplementing without fat in the same meal — D3 is fat-soluble; absorption drops significantly without dietary fat at the same meal
Warfarin — Vitamin K2 affects clotting cascade; monitor INR carefully if on warfarin
Thiazide diuretics — can cause hypercalcemia when combined with high-dose D3; monitor calcium
Calcitonin and bisphosphonates — generally safe; complementary bone health mechanisms
Test before supplementing D3 — about 40% of people are deficient at baseline, and the correct dose depends on your starting level. 5,000 IU D3 + 100 mcg K2 (MK-7) is the most common protocol, but genuinely deficient individuals may need more to reach optimal range. K2 is not optional for chronic high-dose D3 supplementation.
Stats
Sources & Studies
Martineau AR. et al., BMJ, 2017