Consensus Report
Vitamin D
Strong Consensus
out of 5
Based on 182 videos (134 hours analyzed) across the experts · Updated 2026-03-18
Expert Positions
The Verdict
4 of 5 experts recommend vitamin D supplementation for those with suboptimal levels, though Attia urges caution — arguing that the health benefits attributed to high vitamin D may actually come from the outdoor lifestyle needed to achieve them naturally. Patrick is the strongest advocate, citing a 40% reduction in dementia risk.
Where They Disagree
Attia argues that the health benefits attributed to vitamin D may actually come from the outdoor lifestyle (exercise, sunlight exposure) rather than the vitamin itself — a confounding variable that most studies don't adequately control for. Patrick and Hyman disagree, citing intervention studies where supplementation alone improved outcomes.
Optimal blood levels are contested: Patrick and Hyman target 50-80 ng/mL, while Attia is more cautious about overshooting, warning about hypervitaminosis D and noting that assays are unreliable.
+ 2 more disagreements in the full report
About This Analysis
This consensus report on Vitamin D is based on 182 videos (134 hours analyzed) from five longevity experts: Andrew Huberman, Peter Attia, Rhonda Patrick, Bryan Johnson, and Mark Hyman. Each expert's position was independently analyzed from their published video content, including lectures, podcast episodes, and Q&A sessions with 1,000+ guest scientists.
The full report includes 7 key findings, dosage and protocol details, expert deep dives with direct video citations and timestamps, risk considerations, and related supplement synergies.
Frequently Asked Questions
How much vitamin D should you take per day?
Most experts suggest 1,000-5,000 IU of vitamin D3 daily, depending on your baseline blood level and body weight. Hyman recommends testing first and targeting 50-80 ng/mL, and notes higher-BMI individuals may need more since body fat sequesters vitamin D. Patrick says most people need supplementation given widespread deficiency.
When should you take vitamin D?
Take vitamin D with a fat-containing meal for better absorption, since it is fat-soluble. Morning or midday is preferred — there is some evidence that evening doses can interfere with melatonin production. It pairs well with omega-3 at a meal, as both are fat-soluble and can be taken together for optimal absorption.
Is vitamin D3 better than D2?
Yes — the experts recommend vitamin D3 (cholecalciferol), not D2. Hyman notes that fortified foods often use the less effective D2 form and recommends D3, ideally with K2. Attia is explicit too: when he lists vitamin D, he means D3, dosed based on blood-level monitoring.
Should you take vitamin D with K2 or magnesium?
Both pairings matter. Hyman recommends combining D3 with K2 so calcium goes to bones and teeth rather than depositing in arteries. He also has a dedicated video on magnesium, which is required for the enzymatic conversion of vitamin D into its active form — without enough magnesium, supplementation may be ineffective.
Is 5000 IU of vitamin D too much?
Not necessarily. The experts' range runs 1,000-5,000 IU daily depending on baseline and body weight, but the upper safe limit is generally considered 4,000 IU/day without medical supervision. Higher-BMI individuals may need more since body fat sequesters vitamin D. Attia warns about hypervitaminosis D, so testing your level first helps you dose appropriately.
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