I don't doubt you but I also wonder what you base this information on.

In 2020 I test results for vitamin D was ridiculous low. I have been taking supplements

Jan 02, 2020 4:32 pm 25-Hydroxy Vitamin D Total 9 ng/mL 30-100 ng/mL

I took me five years just to get to something close to the lowest end of normal.

I was started on supplements in the in 2k IU and after poor progress boosted to 5k IU everyday to get to this level.

I have been spending the past year on a sailboat instead of server room and look forward to seeing my test results.

A big problem is that the range that we have decided to call “normal” might not actually be a normal range.

For example, 50% of surfers were found to have insufficient vitamin D in one study. https://pubmed.ncbi.nlm.nih.gov/17426097/

There are at least two possible conclusions that you could draw. One conclusion is that we all need vitamin D supplementation regardless of how much sun exposure we receive.

Another conclusion is that we might want to reevaluate what we consider the normal range to be, especially when we are deciding a range for a specific individual.

My own experience getting a too-high result from supplementing 5K IU several times a week. When it came up, my doctor said I wasn't alone and that she's seeing a lot of people come back too high.

> I took me five years just to get to something close to the lowest end of normal.

Five years of supplementing to get up to 30ng/mL? Something is wrong. Could your supplements have not actually contained any real amount of Vitamin D? Certain malabsorption disorders also reduce Vitamin D absorption, for example.