D3 is seldom supplied alone and often it's the fact that vitamin supplements also have D3, in addition to the calcium sources people use. I have seen over supplemented animals. It is next to impossible what was overdosed, since most supplements are a mixture of vitamins and not exclusively D3. Since chameleons are designed to manufacture D3 through the absorption of UVB and not obtain it regularly through diet, it stands to reason we should focus on our UVB and less on supplementing with D3. D3 supplements are best used to fill in where animals may be hiding in enclosure foliage and getting less UVB, from their bulbs, or to catch short falls in general and not to be relied upon for D3 exclusively.
I think people overdose nearly everything, if they are providing a good gutload and then supplementing. No one is dusting feeders with calcium every feeding in nature and constantly supplying loads of it has shown to calcify joints and cause binding of other nutrients. I dust very infrequently and it varies by species and age as to how often and what I use and it's never all of the feeders offered. For my parsons, I over one supplemented item once or twice a week, with plain calcium and even less often with vitamins and D3, which I offer every month to 6 weeks. Now, my gutload is phenomenal and homemade and fed in conjunction with high calcium greens, vegetables, and select fruits. I also fed them an 85% wild caught diet, this Summer. My growing veiled gets supplemented at least once a week with calcium, usually 2-3 times, and about weekly with vitamins. He is outdoors, with natural UVB, so I do not use D3 for him. He also gets well gutloaded feeders and wild caught prey.
I use several vitamin and calcium products, to ensure a broad spectrum of things are well covered, but I believe in smaller, more frequent doses, versus how most people are advised to supplement. I accomplish that with my gutload. I would prefer to supplement small numbers of feeders and offer supplements more often, but the dosages on most supplements are not specific to chameleons, much less montane species. Gullar edema is often the first sign of too much of something and if I'm not seeing any and everyone is growing, eating, gaining weight, and appearing healthy, I assume they aren't missing anything.
