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Fat-soluble vitamins

Vitamin D

Bone · immune

Calcium absorption, bone mineralization, immune modulation.

Daily target
20 mcg
FDA Daily Value
Upper limit
100 mcg
Tolerable Upper Intake
Catalog matches
8
supplements in our catalog

Upper-limit caution

The Tolerable Upper Intake Level for Vitamin D is 100 mcg per day. Routine intakes above this level — counting food + supplements — raise the risk of adverse effects. Multivitamins, fortified foods, and standalone supplements stack faster than people expect.

What Vitamin D does

Vitamin D acts more like a hormone than a classical vitamin: 25(OH)D circulates and is converted to active 1,25(OH)₂D in the kidneys, which regulates calcium absorption, bone mineralization, and immune cell behavior. Most adults in temperate latitudes do not get enough from sun exposure year-round — winter sun above ~37°N is too oblique to drive cutaneous synthesis. Diet alone rarely covers the gap. Below 20 ng/mL serum 25(OH)D is the conventional deficiency cutoff; 30–60 ng/mL is the commonly targeted sufficient range.

Food sources of Vitamin D

Approximate Vitamin D content per serving. Whole-food intake counts toward your daily total alongside any supplemental dose.

FoodServingVitamin D
Wild salmon (cooked)3 oz15 mcg (600 IU)
Cod liver oil1 tsp11 mcg (450 IU)
Fortified milk1 cup3 mcg (120 IU)
Canned sardines (with bones)3 oz4 mcg (165 IU)
Egg yolk1 large1 mcg (45 IU)
UV-exposed mushrooms1 cup10 mcg (400 IU)

Signs of Vitamin D deficiency

  • ●Bone pain, muscle weakness, frequent falls in older adults
  • ●Stress fractures or low bone density on DXA
  • ●Fatigue and low mood that improves with repletion (mechanism debated, association common)
  • ●Severe deficiency: rickets in children, osteomalacia in adults

Who needs more Vitamin D

Groups and situations where Vitamin D requirements rise or status commonly runs low:

  • ●Living above ~37° latitude (Boston, Madrid, Beijing) from October through March
  • ●Darker skin tones — melanin reduces UVB-driven synthesis 3–6×
  • ●Indoor lifestyle, sunscreen-heavy use, full-coverage clothing
  • ●Older adults — skin synthesis drops ~50% by age 70
  • ●Obesity — D is sequestered in adipose tissue and less bioavailable

Forms to avoid

Not all Vitamin D forms absorb equally well. The following forms are commonly used because they're cheap, but their bioavailability is materially lower than alternatives — watch for them on supplement labels:

  • d2
  • ergocalciferol

Formulate's product scoring penalizes these forms when they appear as the primary Vitamin D source — see the methodology page for the rubric.

How Vitamin D appears on labels

Supplement labels list Vitamin D under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your Vitamin D intake:

  • vitamin d
  • vitamin d3
  • vitamin d2
  • cholecalciferol
  • ergocalciferol

Best supplements for Vitamin D

Top-scoring supplements in our catalog that list Vitamin D on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Momentous
Vegan Vitamin D3 5000 IU Supplement
98
Thorne
Vitamin D Liquid
98
Thorne
Vitamin D-10,000
98
Transparent Labs
Grass-Fed Whey Protein Isolate
98
Transparent Labs
Vitamin D3 K2
98
Thorne
Vitamin D + K2 Liquid
98
Nutricost
Calcium + Vitamin D3 Tablets
96
Nutricost
Calcium Citrate + Vitamin D
96

Deep dive

For mechanism of action, dosing protocols, evidence grade, and interaction warnings on Vitamin D, see the full encyclopedia entry:

Vitamin D encyclopedia entry →

Conditions where Vitamin D has evidence

Vitamin D appears on the supplement list for the following condition pages — each links to the full evidence summary, dose, and lifestyle context.

Research on Vitamin D

Peer-reviewed studies in our research database that reference Vitamin D. Each entry links to a detailed methodology review.

Guides covering Vitamin D

Long-form articles in our guide library that go deeper on Vitamin D — comparisons, protocols, and reviews.

Frequently asked questions

What is the daily target for Vitamin D?
The fda daily value for Vitamin D is 20 mcg per day for adults. The Tolerable Upper Intake Level is 100 mcg/day from food and supplements combined.
What foods are highest in Vitamin D?
Wild salmon (cooked) (15 mcg (600 IU) per 3 oz); Cod liver oil (11 mcg (450 IU) per 1 tsp); Fortified milk (3 mcg (120 IU) per 1 cup). See the food sources section below for the full list.
What is the best form of Vitamin D to supplement?
D3 (cholecalciferol) raises serum 25(OH)D more efficiently than D2 (ergocalciferol). Take with a fat-containing meal for absorption. K2 (MK-7) pairing is reasonable but optional.
What are the signs of Vitamin D deficiency?
Bone pain, muscle weakness, frequent falls in older adults; Stress fractures or low bone density on DXA; Fatigue and low mood that improves with repletion (mechanism debated, association common).
Who is most at risk for low Vitamin D?
Living above ~37° latitude (Boston, Madrid, Beijing) from October through March; Darker skin tones — melanin reduces UVB-driven synthesis 3–6×; Indoor lifestyle, sunscreen-heavy use, full-coverage clothing.

Related fat-soluble vitamins

Track your full intake

Formulate's free web app aggregates Vitamin D (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.

Track your intake free →

Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.