Supplement Comparison
Take D3, not D2. D3 (cholecalciferol) is the form to take, often paired with K2 for calcium metabolism. Fortified foods often use the less effective D2.
The verdict on Vitamin D overall
Leaning for
Vitamin D supplements are worth taking.
12 sources: 6 positive, 6 partly
Each claim gets one verdict, worked out from every counted mention. One dot is one source: a researcher or a study. Tap a dot to see its receipt.
positive partly neutral negative Each researcher and each study counts once per claim, however often they come up.
Vitamin D3 works better than vitamin D2.
No counted mention yet.
Researchers say
No researcher counted yet.
Studies show
No study counted yet.
Vitamin D3 raises blood vitamin D levels higher and longer than vitamin D2.
No counted mention yet.
Researchers say
No researcher counted yet.
Studies show
No study counted yet.
Built from every credited researcher and cited study on each claim.
Vitamin D supplements are worth taking.
Dr. William Li, 2 mentions on this claim
Positive Video
on Rangan Chatterjee's channel, at 55:25 · positive
“it's a lot easier to get your regular dose of daily vitamin d um by actually just having d3 supplements”
on Rangan Chatterjee's channel, at 58:54 · positive
“it's a lot easier to get your regular dose of daily vitamin d um by actually just having d3 supplements”
Andrew Huberman, on Huberman Lab, at 1:47:13
Positive Video · Opinion
Open the tape at 1:47:13 →“supplementing with anywhere from a th000 to 2,000 IU of vitamin D per day is probably safe for most people”
Dr Vonda Wright, on The Diary Of A CEO, at 1:17:26
Positive Video · Opinion
Open the tape at 1:17:26 →“it's something that everyone should supplement they should get their level checked”
Rhonda Patrick, 2 mentions on this claim
Positive Video
on FoundMyFitness, at 03:22 · positive
“there's a simple solution and that's why I like to talk about and that solution is actually taking a vitamin D supplement.”
on FoundMyFitness, at 42:57 · positive
“I currently supplement with 4,000 IU's per day and my levels are consistently 50 nanograms per”
Mark Hyman, 5 mentions on this claim
Positive Video
on The Dr. Hyman Show, at 40:05 · positive
“the range I usually recommend is two to 5,000 units a day”
on The Dr. Hyman Show, at 06:20 · positive
“it's important to make sure we we get adequate levels of vitamin D probably mostly through supplements”
on The Dr. Hyman Show, at 03:40 · positive
“for most people a good multi fish oil and vitamin D will do the trick”
on The Dr. Hyman Show, at 14:49 · positive
“your dose should be between a th000 to 5,000 units a day some people need 10,000”
on The Dr. Hyman Show, at 02:51 · positive
“i recommend at least a multi official vitamin d”
Andy Galpin, on The Diary Of A CEO, at 22:30
Positive Video · Opinion
Open the tape at 22:30 →“pretty good chance to be effective pretty low risk I'm okay with people really pushing vitamin D”
Elizabeth Boham, on The Dr. Hyman Show, at 12:23
Partly Video · Opinion
Open the tape at 12:23 →“they do better if we support with some supplementation for a period of time”
Dr. Kyle Gillett, on Huberman Lab, at 18:12
Partly Video · Opinion
Open the tape at 18:12 →“if you have deficient vitamin D, and you replace it, then you will optimize your testosterone.”
Roger Seheult, 2 mentions on this claim
Partly Video
on Rangan Chatterjee's channel, at 26:48 · partly
“in all of the patients that i am seeing in the hospital that are coming with cover 19 we're putting them on vitamin d supplementation”
on Rangan Chatterjee's channel, at 15:01 · partly
“supplementation with up to 4 000 international units a day probably would be beneficial especially if you're not able to get a lot of sunlight”
Chris Kresser, on The Dr. Hyman Show, at 15:01
Partly Video · Opinion
Open the tape at 15:01 →“so someone who's obese might need to take 10 000 IU of uh per day of vitamin D just to maintain a normal level yeah versus someone who's lean maybe 2000 IU would be sufficient”
Stuart Phillips, on FoundMyFitness, at 1:36:22
Partly Video · Opinion
Open the tape at 1:36:22 →“Definitely, in the winter months, vitamin D is, yep, absolutely.”
Gordon Lithgow, on FoundMyFitness, at 30:44
Partly Video · Opinion
Open the tape at 30:44 →“it's likely that if you are deficient, you really would benefit from coming up into a sensible range.”
Precis is not affiliated with or endorsed by YouTube or by any researcher, show or publisher we quote. We take no sponsorship, ad or affiliate money, and every verdict is our own review of what was said. How we stay independent
Source
Vitamin D3 (Cholecalciferol)
Animal-derived (lanolin, fish oil) — same form your skin makes from sunlight
Vitamin D2 (Ergocalciferol)
Plant/fungal-derived (irradiated mushrooms, yeast)
Potency
Vitamin D3 (Cholecalciferol)
Raises blood levels more effectively and maintains them longer
Vitamin D2 (Ergocalciferol)
Less effective at raising 25(OH)D levels — shorter half-life
What the sources say
Vitamin D3 (Cholecalciferol)
The form named for supplementing
Vitamin D2 (Ergocalciferol)
Not recommended over D3; most fortified foods use it
Blood Level Impact
Vitamin D3 (Cholecalciferol)
Sustains blood levels for weeks. Better at achieving target range
Vitamin D2 (Ergocalciferol)
Blood levels drop faster. Less reliable for maintaining optimal range
K2 Pairing
Vitamin D3 (Cholecalciferol)
Often paired with K2 to direct calcium to bones
Vitamin D2 (Ergocalciferol)
K2 pairing less discussed with D2 since it's not the recommended form
Availability
Vitamin D3 (Cholecalciferol)
Widely available as standalone supplement
Vitamin D2 (Ergocalciferol)
Often used in fortified foods and prescription-strength supplements
Take vitamin D3, not D2. This is one of the clearer form choices in supplements. D3 is the same form your skin makes from sunlight, it raises blood levels more effectively, and it keeps them up longer than D2. One nuance: pair D3 with K2, which directs calcium to your bones rather than your arteries. The common pitfall is relying on fortified foods (milk, cereal), which typically use the less effective D2 form. Get a 25-hydroxy vitamin D blood test, target 50-80 ng/mL, and supplement with D3+K2 to fill the gap. Almost everyone living above 35 degrees latitude needs to supplement, especially in winter.
A free account opens the dose and timing for each form, with the interactions to watch. Pro adds chat about your own stack.
Cancel anytime