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Strong evidenceVitamins

Vitamin D3

Also called: Cholecalciferol; often paired with vitamin K2 (MK-7)

The sunshine vitamin. Many Indians test low despite plenty of sun, and low levels are linked with tiredness, aches and weaker bones.

Typical amount
600–2,000 IU a day (RDA 600 IU)
Best time
Morning or lunch, with the main meal · Timing guide
Food
With a meal that contains fat
Typical course
12 weeks, then review
Upper limit
4,000 IU a day from all supplements; never 60,000 IU sachets without a prescription
Is it right for me?

Where to buy

3 products
Also inside 12 other products (combinations and multivitamins)

What is Vitamin D3?

Vitamin D3 is the form of vitamin D your skin makes in sunlight. It helps the body absorb calcium and supports bones, muscles and immune function. Indoor jobs, sunscreen, darker skin, pollution and covering clothing all reduce how much the skin makes, which is why low levels are so common in Indian cities. K2 is often added because it helps direct calcium into bone.

Forms. Tablets, softgels, oral strips and drops. D3 (cholecalciferol) raises blood levels better than D2. High-dose 60,000 IU sachets are prescription products and are dosed by a doctor.

What it may help with

Evidence grade

Strong: several good human trials. Moderate: some trials, mixed results. Limited: small or early studies. Traditional: long use, little trial evidence.

Safety and interactions

Side effects
Very safe at normal doses. Too much over months can raise blood calcium (nausea, thirst, confusion), so don't stack several D3 products.
Who should be careful
Kidney stones, high calcium, sarcoidosis: doctor first; K2 versions: blood thinners doctor first
Spacing
Count D3 in every product (multivitamins, calcium) toward the total
Stop and call a doctor if
Nausea, constipation, confusion, excessive thirst

Food sources

Fatty fish, egg yolk, fortified milk and oils, sun-dried mushrooms. Food alone rarely covers needs; 15–20 minutes of midday sun on arms and legs helps.

Common questions

Should I test before taking vitamin D?

It's the best way to know your dose. Ask for a 25-OH vitamin D test; recheck after about 3 months.

Why take it with K2?

K2 helps the body use calcium properly. People on blood thinners like warfarin should ask their doctor before taking K2.

Is morning or night better?

Either works. Take it with your main meal, because it needs some fat to be absorbed.

Sources

For information only, not medical advice. Prices and links are checked by hand and can change; we may earn a small commission on some links. This plan is based on your answers and is not a medical diagnosis. It does not replace advice from your doctor. If you take medicines or have a health condition, check with your doctor before starting any supplement.