Expert Answer
Is vitamin D3 better than D2?
Quick Answer
Yes. Four of 5 experts specifically recommend D3 (cholecalciferol) over D2 (ergocalciferol). D3 is the same form your skin makes from sunlight, raises blood levels more effectively, and maintains them longer. Hyman goes further: always pair D3 with K2.
Strong Consensus
on Vitamin D overall
What Researchers Say
Explicitly states 'when I say vitamin D, I mean D3.' Includes D3 in his personal stack.
Always D3, never D2. Warns fortified foods use inferior D2. Always pairs D3 with K2.
Cites 40% lower dementia risk with D3 supplementation.
Detailed Answer
D3 is definitively better than D2. D3 (cholecalciferol) is the same form your skin produces from UVB sunlight, raises blood levels more effectively, and has a longer half-life than D2 (ergocalciferol).
Attia is direct: "When I say vitamin D, I mean D3." Hyman warns that fortified foods often use the cheaper D2 form and recommends always pairing D3 with K2 for calcium metabolism. Patrick's research on D3 shows a 40% lower dementia risk and links deficiency to 5 years of accelerated aging.
Vegan D3 from lichen is now widely available for those who prefer plant-derived sources.
Related Questions
Are fortified foods enough for vitamin D?
Probably not. Hyman warns fortified foods use inferior D2 form. Most experts recommend supplementing with D3.
More Questions About Vitamin D
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