I have taken supplements, but they are not very effective. Honestly, I don't want to rely on medication when our bodies are perfectly suitable with enough sunlight exposure.

I've been researching this for a while and can't find sources that show the difference according to latitude. I stupidly didn't bookmark what I read so what I say is based on what I've read but can't link to any of it :(.

• I gather there is research that around noon time sun exposure (e.g. 11am-3pm) results in greater production. The skin's processes are optimised for that time.
• I am very aware of the risks of skin cancer.
• I read in the UK about 13 minutes for 3 days a week, just between April and September is adequate for vitamin D levels year round.
• I live on the tropic of cancer so I'm expecting perhaps 7-10 minutes. Anything specific to that sub-tropical latitude would be greatly appreciated.

All advice is welcome, but links that I can read, compare and digest myself especially for different latitudes round the world would be perfect.