It was pretty similiar for me as well. In NRW, Germany. I was at <4 µg/l (not measureable). Welp. Took 20k/Week for 8 weeks as well. Felt a lot better, don't know my after result though.

The problem for me was. A few months later I was down to ~7ish again. Looks like I need a daily supplement then.

How did you feel before/after?