Sunlight and skin: balancing cancer risk against vitamin D and mood
September 29, 2026 · 24 min read
Dermatologist Teo Soleymani and Huberman's skin episode discuss how much sun is safe and whether avoiding it shortens life, while Roger Seheult and Huberman's light episode highlight sunlight's immune and hormonal benefits. Readers get a nuanced view beyond 'always avoid the sun'.
The rules, numbers and steps worth keeping in front of you.
- Agreed by all: some sun is healthy, and burning is the line not to cross.
- Teo Soleymani: no fixed safe time; cover up or go in before your skin starts to redden.
- Andrew Huberman: aging and mutations happen below the burn threshold.
- Midday, roughly 10 or 11 a.m. to 2 to 4 p.m., is the most intense window; check the UV index.
- Doses are modest: 15 to 20 minutes on the forearms for vitamin D (Soleymani); 15 to 30 minutes a day (Roger Seheult).
- Huberman's hormone protocol: 20 to 30 minutes on arms and legs, two or three times a week, no burning.
- Shade, clothing and hats come first; Soleymani says they work better than sunscreen.
- Sunscreen: mineral, broad spectrum, SPF 30 or higher; zinc oxide alone is the most cautious choice.
- No chemical sunscreen for babies six months or younger.
- Seheult: glass blocks UVB, so a sunny window will not make vitamin D.
- Seheult: darker skin and living above the 35th parallel raise deficiency risk; get tested.
- Seheult: 4,000 IU a day is the Endocrine Society's maximum without a doctor's supervision for at-risk people.
- Yearly full-body skin check, including scalp, between toes and genitals.
- See a dermatologist for a spot lasting over a month or seeping for weeks, or with any skin cancer history.
This is the short form. The full insight has every expert's reasoning, their own words and the sources.