With Professor David Anderson. Link to order or download, Vitamin D and the Great Biology Reset, dgreatbiologyreset.com/

Professor David Anderson (retired endocrinologist) emphasizes the importance of vitamin D3, especially for those in northern locations where sunlight exposure is limited in winter.
Vitamin D is primarily produced when skin is exposed to sunlight (UVB rays); Professor Anderson argues most people are deficient and should supplement year-round.
According to Anderson, a blood level above 50 ng/ml (125 nmol/L in UK units) is necessary for proper immune function and to protect against various diseases.
Professor Anderson claims that vaccinations deplete vitamin D levels, particularly the "reservoir form" (calcifediol), and he and his wife take supplements to counteract this effect.
The professor takes 100,000 units of vitamin D3 monthly (via oil-based solution) and personally takes either daily supplements (5,000-10,000 units) or calcifediol weekly, Overweight individuals may need higher doses and should titrate with blood levels under their doctors.
Anderson and co-author David Grimes have published books on vitamin D deficiency and COVID-19, available as free PDF downloads from their website.
He claims vitamin D is protective against some cancers, assists brain repair after strokes, and is linked to preventing numerous other health conditions.
Anderson expresses concerns about pharmaceutical companies being opposed to vitamin D supplementation, alleging they profit from keeping people vitamin D deficient.