calcium with D3 or without

hey all, What the difference with calcium powder with or without D3 in it? i just got a Argentine b&w tegu and i bought it with D3.... is that okay or do i need to get the one without D3? someone with some exprience please help and try to explain what d3 does. thanks!

Vitamin D is the sunlight vitamin. It comes in several forms, of which D3 is the most effectively metabolized. D3 is formed in the skin when a reptile basks in the sun, or it can be absorbed from the food. Both calcium and D3 are required to form bone. Lack of sufficient vitamin D and/or calcium causes metabolic bone disease in reptiles and rickets in mammals. I'd use the calcium and D3 combination rather than calcium alone. But I have little experience with lizards, so YMMV.

https://en.wikivet.net/Lizard_Metabolic_Bone_Disease
https://en.wikipedia.org/wiki/Rickets

If your tegu is getting natural sunlight or you're using high quality UVB bulbs, you want to use D3 sparingly - if at all.