Reptical has D3 in it I believe. What you want is a phos.-free calcium powder like Rep-Cal and also a phos.-free calcium powder like Rep-cal with D3...and a vitamin powder that has a beta carotene source of (prOformed) vitamin A such as Herptivite. Some chameleons may need prEformed vitamin A so some people use a powder such as Reptivite once in a while to ensure that they get some. D3 from supplements and prEformed vitamin A can build up in the system so you need to be careful using them. Excess prEformed vitamin A may prevent the D3 from doing its job and lead to MBD. D3 from sunlight/UVB lights should not build up in the system as long as the chameleon can move in and out of it.
D3 calcium, phosphorus and vitamin A are important players in bone health and in other systems in the body and need to be in balance. You need to look at how much of each is in not only the supplements you use but also the gutload.
I use a wide variety of greens (dandelions, collards, kale, endive, escarole, etc.) and veggies (carrots, squash, sweet red pepper, sweet potato, zucchini, etc.) to gutload/feed crickets, locusts, superworms, etc.
Temperature is also important indirectly in nutrient absorption in that reptiles need heat to digest their food properly...and of course, exposure to UVB allows the chameleon to produce D3 to help in the calcium absorption.
Hope this helps!
