Mark Bell's Power Project The Vitamin D Lie: Why Supplements Don’t Work Like Sunlight
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Jan 21, 2026 David Herrera, a health and physiology commentator specializing in sunlight and circadian biology, reveals the hidden dangers of sun avoidance. He explains why sunscreen use in low UV conditions can be counterproductive and discusses the intricate ways that UV light affects hormone production beyond just vitamin D. Herrera argues that oral vitamin D supplements fail to replicate the benefits of sunlight, often masking underlying health issues. He also contrasts dietary and supplemental vitamin D, emphasizing the importance of natural sources.
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Everyday Sunscreen Overuse Example
- David Herrera describes his girlfriend and friends applying sunscreen even in low UV winter conditions around Sacramento.
- He uses this personal example to show how deep sun avoidance has become and how common sunscreen-overuse is.
Sunlight Influences Hormones And Neurochemistry
- Herrera links chronic sun avoidance to higher risk of vitamin D deficiency, low sex hormones, and neurotransmitter problems.
- He emphasizes that UV exposure is needed for vitamin D, sex hormone production, and certain neurotransmitters.
Don't Replace Sunlight With Pills
- Avoid treating oral vitamin D pills as equivalent to sunlight-produced vitamin D because the vitamin D receptor acts at the mitochondrial membrane.
- Recognize that supplement form and carrier oil (fish-derived DHA vs seed oil) affect how vitamin D is used in the body.