Supplement profile

Vitamin D3 + K2

Core supplementLongevityHormone HealthMuscle BuildingRecovery

The foundational hormone stack — critical for testosterone production, immune function, bone density, and GH receptor sensitivity.

Evidence Level

Anecdotal
Emerging
Moderate
Strong

Dosage

2,000–5,000 IU Vitamin D3 + 100–200mcg Vitamin K2 (MK-7 form)

Timing

With your largest meal — fat-soluble, requires dietary fat for absorption

Form

capsule, softgel, drops

How it works

Vitamin D3 functions as a steroid hormone, binding nuclear receptors in virtually every cell type. Deficiency (extremely common in Australians despite high sun exposure due to indoor lifestyles and sunscreen use) directly impairs testosterone synthesis and GH signalling. K2 ensures calcium from D3 supplementation is directed to bone rather than arteries.

What to look for

Ensure D3 (cholecalciferol) not D2. K2 must be MK-7 form (menaquinone-7) not MK-4 — MK-7 has a much longer half-life. Test your 25(OH)D blood level before starting — many Australians are deficient even in summer.

Our recommendation

Buying Vitamin D3 + K2

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Look for third-party tested products with verified purity, correct form and dosage. Avoid proprietary blends and underdosed formulations.

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Pairs with these peptides

Vitamin D3 + K2 directly amplifies the effects of these peptide protocols.

Protocols using Vitamin D3 + K2

These clinician-reviewed protocol stacks include Vitamin D3 + K2 as part of their supplement plan.

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Medical disclaimer

The information on this page is for educational purposes only and does not constitute medical advice. All peptide and supplement therapies should be discussed with an AHPRA-registered medical practitioner before use. ProtocolHub does not prescribe, dispense, or supply any therapeutic goods. Always consult a qualified healthcare professional before starting any new health protocol.