Yes. I turned vegan in 2017 but didn't pay attention to my sun-avoiding lifestyle. A year later I was convinced I had osteoporosis and/or arthritis, because both run in my family.

Doctor had blood tests done, and Vit D was on the floor. Since then I have taken 10,000ius daily under her ongoing supervision.

It took a long, long time to start to get better - maybe 14 months, and it's not done yet.

I also take zinc, magnesium and K2, since these have related benefits for the absorption of vitamin D.