Because they can probably doesn't mean they should though right... ? It seems, to me, a lot simpler and less hassle to slap a decent UVB light in an enclosure than it does to frick about with supplements in every second feed and risk adverse health problems. You wouldn't even save any $$$ doing it that way either...
Providing a natural varied diet and UVB without supplementations will always be better for the reptile rather than no UVB lighting and instead, cramming them full of supplementations at every second or third feed. The problem with multi vitamin and calcium powders, sachets etc is they cause a drastic and extremely rapid rise in the blood levels of whatever is being supplemented and that isn't natural or normal and has been directly linked to gout in reptiles, hypervitaminosis A, D etc and hypecalcemia. I don't dare use any dietary supplements for my frogs and turtles, have never dusted an insect. Just provide a normal natural variation in their diet, UVB lighting and some time in the sun a few times each week and let nature do what it does best.
[doublepost=1517978465,1517978228][/doublepost]Just like we can't supplement a good breakfast with 3 cans of redbull.