Vitamin D3

A clear benefit only if you are starting from low levels.

• Tier B — Moderate evidence — useful in specific contexts
• Health

What it is for

Bone health and treatment when indicated; not a general performance, immunity or mood booster.

How it works

A steroid hormone involved in bone health, muscle function and immunity; deficiency is very common.

Dosing

Generally healthy adults should not routinely target 30–50 ng/ml or supplement above recommended intake without an indication. Reference total intake is 600 IU/day through age 70 and 800 IU/day thereafter; deficiency treatment requires individual assessment.

When to take it

With a meal containing fat for better absorption.

Safety

Safe within the recommended range.

Side effects

Excess can cause hypercalcemia and kidney damage. Safety depends on dose, duration and coexisting conditions.

Interactions

Review medications and total calcium and vitamin D intake. Routine K2 addition is not a required combination.

Contraindications

Hypercalcaemia, sarcoidosis (seek medical advice).

Who it has been studied in

Very relevant with low sun exposure, darker skin, older adults.

Frequently asked