Vitamin D3

Vitamin

Most adults are deficient. Affects 1000+ genes including immunity, mood, and bone health. Pair with K2 to direct calcium into bones, not arteries.

immunebonemooddeficiency-correction

Typical dose

1000–4000 IU daily

Evidence

Strong (multiple RCTs / meta-analyses)

Onset time

Cumulative: 8–12 weeks

Half-life

~3 weeks

Forms

Softgel, Capsule, Liquid, Tablet

Source

animal

Best taken with

fat-containing meal

Best time of day

morning

Bioavailability

4/5

Safety rating

4/5

Price per serving

$0.08

Vegan / GF / 3rd-party

✗ / ✓ / ✓

Find Vitamin D3iHerb →

Vetted brands, third-party testing, ships worldwide.

Common uses

• Deficiency correction
• Bone health
• Immune support
• Mood / SAD

Effect profile

Strength

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Muscle

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Energy

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Focus

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Mood

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Sleep

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Immunity

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Recovery

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Longevity

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Common side effects

• Hypercalcemia (very high doses)

Avoid if

• Hyperparathyroidism
• Sarcoidosis
• Kidney stones

Drug interactions

• Statins
• Thiazide diuretics
• Steroids

Related vitamin supplements

Vitamin D3 vs Vitamin K2 (MK-7)Vitamin D3 vs Vitamin C Vitamin D3 vs Vitamin E (Mixed Tocopherols)Vitamin D3 vs Vitamin B12 (Methylcobalamin)Vitamin D3 vs Methylfolate (5-MTHF)Vitamin D3 vs Biotin (B7)

Medical disclaimer

SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements.