Here is the Dr John Campbell video for those who haven’t seen it:
Lots to say on this topic but I wanted to make some things available.
Firstly here is the paper
Lee and Broudy 2024
Despite taking 4,000 to 8,000 units per day for the past few months. National Institute for Health and Care Excellence NICE Do not routinely test for vitamin D deficiency in people who are asymptomatic. https://cks.nice.org.uk/topics/vitami… Check the vitamin D level by measuring serum 25-hydroxyvitamin D (25[OH]D) if a person has: Musculoskeletal symptoms Suspected osteomalacia. Chronic widespread pain with other features of osteomalacia (such as proximal muscle weakness). Suspected bone disease that may be improved with vitamin D treatment, such as osteomalacia or osteoporosis. Known bone disease, where correction of vitamin D deficiency is needed prior to specific treatment, such as: Prior to Paget’s disease treatment with a bisphosphonate. Note: asymptomatic people at higher risk of vitamin D deficiency do not need routine testing for vitamin D deficiency, but should be advised on the need for maintenance dose vitamin D supplementation.
…