[TexasGator]

“Direct sunlight is the most efficient way to increase vitamin D in the blood. Oral vitamin D requires multiple synthetic steps that rely on vitamin K2, magnesium and restriction of fructose containing foods. The kidneys are the bottleneck in the oral vitamin D pathway.”

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Conclusion: Vitamin D supplementation was more effective than sun exposure at increasing serum 25(OH) D3.

https://pubmed.ncbi.nlm.nih.gov/31107101/#:~:text=Conclusion%3AVitamin%20D%20supplementation%20was%20more%20effective%20than%20sun,or%20applied%20UVB%20treatment%20instead%20of%20direct%20sunlight.

[Myrddin]

Two different paths for vitamin D. Since I live in Pocatello at N43 latitude and work in my basement, I must supplement with oral D3/K2. My Scot/Welsh/Irish genetics make tanning a disaster. It's always burn and peel. Never a real tan.

My daily intake is D3 10000IU and K2 500 mcg. I take 400 mg magnesium daily that helps with the D3 absorption and prevents cramped calf muscles.