Sunlight
For general health and circadian biology
The experts we follow agree on this.
Regular sunlight exposure supports vitamin D, thyroid, and healthy circadian rhythms.
Who is behind it
Voices including a molecular biology PhD, a board-certified endocrinologist and a board-certified internal medicine doctor.
How strong the research is
Backed by some published research, and by what the experts see in practice.
In their words
“This needs to be a non-negotiable part of the routine for them... we actually get free energy from sunlight.”
an optometrist of twenty years
UVB light is necessary for vitamin D synthesis from cholesterol and UVA triggers thyroid stimulating hormone
Proper circadian habits and sunlight exposure help produce important peptides like POMC-derived peptides which are crucial for health.
Aligning with the rising and setting of the sun supports fascial health by respecting the circadian rhythm of fascial cells.
Sunlight boosts mitochondrial energy and thyroid hormones.
Sunlight helps raise Tregs which are crucial for immune regulation and preventing autoimmunity.
UV light exposure stimulates POMC which cleaves into Alpha-MSH that suppresses appetite and increases energy expenditure naturally.
Sunlight and fresh air are natural resources that support the body's innate healing ability.
Sunlight provides free energy in the form of electrons that build up the body's electrical charge, which is essential especially during illness.
Where they disagree
Both sides
For
UVB light is necessary for vitamin D synthesis from cholesterol and UVA triggers thyroid stimulating hormone
a molecular biology PhDAgainst
Weight loss drugs alone do not sustain health; behavioral changes are necessary to maintain weight loss and metabolic health.
a board-certified endocrinologistMost of the minds come down in favour, and the dissent is worth knowing.
Talk it through
Entrain shows what the experts teach, so you can make better decisions with your own clinician. It does not diagnose or prescribe. If something is worrying you, start there.
How this reading was made
Every line here comes from a doctor, scientist or coach speaking publicly, and links to the moment they said it. Entrain listens for where independent experts arrive at the same place on their own, and shows where they part ways. Backed by some published research, and by what the experts see in practice.
None of the statements here come with a declared commercial interest. Last refreshed 23 September 2026.
The research beneath it
- Sunlight: Time for a Rethink?The Journal of investigative dermatology, 2024
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