Comparing Vitamin D3 Supplements

125 mcg (5,000 IU)

Quick and concise comparison of Vitamin D3 from quality certified brands.

Grouped by potency
Ordered by cost per microgram
Deciders easily comparable

Benefits of Vitamin D

According to Examine’s excellent Human Effect Matrix, the benefits of Vitamin D include:

  • Improved immunity especially in regards to upper respiratory tract infections.
  • Reducing the severity of COVID-19.
  • Improving bone health.
  • Can reduce the risk of diabetes and multiple sclerosis.
  • A reduction in mortality from all causes.

The above benefits are likely only relevant if the amount of Vitamin D in the blood is low.

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How is Vitamin D absorbed?

Because it is a fat soluble vitamin, when taken orally, Vitamin D should be consumed with food that contains fat. Liposomal Vitamin D contains fat and can be absorbed without food.

Vitamin D is synthesized in the skin from ultra violet light in the form of UVB rays from the sun. Therefore, people with limited exposure to the sun may need more Vitamin D than they get from their diet.

The sun creates Vitamin D3 from the skin. This is either stored in fat cells or converted by the liver and then kidneys to calcitrol. Calcitrol is the form of Vitamin D that the human body uses. The liver and kidneys can also convert Vitamin D2 into calcitrol.

Vitamin Inspector has chosen to compare Vitamin D3 as it has been shown to be more effective than Vitamin D2 in raising levels of Vitamin D in the blood.

Read more about Vitamin D at the Linus Pauling Institute’s Micronutrient Information Center.

Safety and Potency

According to the US Government’s National Institute of Health (NIH), the recommended daily allowance (RDA) for Vitamin D is 15 mcg for both male and female humans in the age ranges of 1 to 69 years. For those over 70 years the RDA is 20 mcg.

The tolerable upper intake is 100 mcg per day for people over the age of 9 years. And less for those under 9 years.

This data is correct as at 30 July 2022.

See Recommended Dietary Allowances and Adequate Intakes, Vitamins.

See Tolerable Upper Intake Levels, Vitamins.

Comparison of Vitamin D3 – 125 mcg (5,000 IU)

California Gold Nutrition
NOW Foods
Thorne Research
Natural Factors
California Gold Nutrition Vitamin D3 125 mcg
NOW High Potency Vitamin D-3 5000 IU
Thorne D-5000
Natural Factors Vitamin D3 Vegan Bio enhanced 5000 IU
$ per 100 mcg






360 Softgels

120 Softgels

60 Capsules

60 Vegetarian Capsules

$ per serve





Other factors

Quality certifications p



Active Ingredients

Vitamin D (D3 as Cholecalciferol from Lanolin)

Vitamin D3 (as Cholecalciferol) (from Lanolin)

Vitamin D (as Vitamin D3)

Vitamin D3 (cholecalciferol, lichen) (whole)
Other ingredients
California Gold Nutrition Vitamin D3 125 mcg Ingredients
NOW High Potency Vitamin D-3 5000 IU Ingredients
Thorne D-5000 Ingredients
Natural Factors Vitamin D3 5000 IU Ingredients


Vitamin D3
25 mcg 1,000 IU


Vitamin D3
50 mcg 2,000 IU


Vitamin D3
125 mcg 5,000 IU

Quality certifications

ISURA logo

ISURA is an independent Canadian and US company who test food and supplements. They test Natural Factors supplements for contaminants.

iTested logo

iTested is a label that the supplement website iHerb gives to products that are tested by indepdendent laboratories. They are tested for label accuracy and contaminants every six months.

NSF logo

National Sanitation Foundation (NSF) are an independent organisation that conduct supplement quality testing and also audit plant and processes of supplement manufacturers for adherence to good manufacturing standards.

Underwriters Laboratories (UL) logo
Underwriters Laboratories (UL) audit supplement manufacturers’ businesses for compliance and provide good manufacturing process certification.


p Liposomal Vitamin D: Because Vitamin D is fat soluble, it should usually be taken with food. Liposomal Vitamin D contains fat which means it can be consumed on an empty stomach.

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