I keep seeing this on different threads.

Be careful with supplements containing fat-soluble compounds , of which Vitamin D is one. Vitamin D is a hormone. Careful!

Same goes for any metals.

Taking supplements occasionally shouldn't be harmful. A vitamin D supplement every once in a while should be ok, specially if you are locked up and not getting sufficient sunlight.

The key being "occasionally". However, if you routinely take them, please have a checkup done on the next opportunity you get. If you don't have any deficiencies, you shouldn't need supplementation.

Vitamin C should be fine. It is water-soluble, excess can be disposed of, if your kidneys are normal.

Also, get your blood work done regularly and do your annual checkups with your Doctor. There's no reason to guess that you might be vitamin deficient, you can just go check.

It sounds like to two of you (and downvoters) didn't read my post closely enough and/or not up on recent research:

https://pubmed.ncbi.nlm.nih.gov/32252338/

https://www.webmd.com/lung/news/20200518/more-vitamin-d-lowe...

Most folks are deficient, and it is difficult, though not impossible to overdo it. Also, if you are living at 35+ degrees latitude, dark skinned, or ~50+ years old, you are deficient.

Your warnings to be careful are careful in the wrong direction, ie. dangerous.

Just found this on the front page!:

https://www.sciencedirect.com/science/article/pii/S096007602...

https://news.ycombinator.com/item?id=24366006