Show me some proof!


I'm currently in a discussion elsewhere regarding the synthesis of D3 in reptiles.

The care guide states (and many veterinary sources say the same) that:

Excessive vitamins in the diet, especially vitamin D3, can lead to toxicity, and some species are more sensitive to overdose toxicity than others. In this case more is not always better. All commercial brands are unique and require different supplementation schedules. It's important to understand what you're doing and the risk of toxicity.
See species specific caresheets for dusting schedules and related details.

However, I cannot find ANY PROOF that the levels of D3 in commercial supplements have caused toxicity in chameleons, or indeed other reptiles. There is plenty of anecdotal evidence, but where are the numbers? Where are the peer-reviewed sources?

Anyone find anything that I can't?


New Member
I would just go off the other lizard examples in this case. Chameleons aren't as widely kept as say leopard geckos or crested geckos. They are thought of as expert species and many people don't take the risk of caring for these wonderful unique animals. We have two very active vets that will probably chime in. These two are ferretinmyshoes and Dr.O. I will toss dr.o a email alerting him to this thread so try and get a response for you on a professional level.


Avid Member
Just a quick google search. Just typed in "Vit d toxicity in reptiles". You can vary the wording and get different results for chameleons or whatever you want. Im sure it is out there. Just have to dig :).

Believe me, if you choose to test it with chameleons. Your animal will suffer in the end.

Zen Reptiles

Avid Member
Mass anecdotal evidence is often more reliable than 'expert' advice because it's based on many individual experiences instead of one persons research because they have a degree and some petri dishes....additionally, most 'experts' are peddling/endorsing a product with their name on it.

Vitamin D3 can build up & cause toxicity in many vertebrates....including you. It is a hormone, not a vitamin, and is produced naturally in the body when exposed to UV radiation (similar to photosynthesis). The body *stops* making it naturally when it's got enough, which is why hypervitaminosis D can be caused by trying to artificially 'fill past full' by using supplement doses, which the body is unable to regulate.

Because exposure to UV radiation is a key factor and varies to great extremes between each individual organism, thresholds haven't even been set for humans don't expect anything too concrete for chameleons anytime soon.

Also, if there are no regulations on the quality of the human-grade calcium & vitamin D (and every other 'natural foods' supplement) that we buy in stores, don't expect the 'guaranteed analysis' of reptile supplements to be at all accurate either.

Just my thoughts.


@ataraxia Thank you, but this is not a peer-reviewed source such that I am looking for.

@zenreptiles Although there is likely truth to mass anecdotal evidence (which is why I supplement according to this website's care sheets and not willy-nilly D3 every day), they will not hold up against scientific scrutiny. What I am looking for is peer-reviewed sources that could be used in a similar research publication as a reference. The trouble with anecdotal evidence is it is not controlled. We don't have measured amounts of D3 supplementation, there's no control group, and no statistical significance when you're essentially taking multiple sample sizes of 1.

The fact that many studies are conducted by companies to shed their supplements in a good light is why we must also not take all peer-reviewed sources as gospel. As an undergraduate, we read poor peer-reviewed papers to prove this point -- we must read our sources with a critical eye to spot bias or poor sampling methods.

The real reason I'm asking this question is because, well, I'm trying to find gaps or holes in research that I could potentially study someday. I get overexcited and start asking the community hard questions when I feel like I might be on to something.


Believe me, if you choose to test it with chameleons. Your animal will suffer in the end.

Ah, I missed this. You are not the first person to go and assume that because I'm asking these questions that I'm going to go out and torture beautiful pet chameleons. I have my own chameleon on the supplementation schedule recommended by this site. I just like to ask challenging questions.


You are awesome! Thank you! I wasn't necessarily looking for chameleons. Just reptiles in general.

Edit: Darn, the second one is in a database I no longer have access to. My university doesn't allow alumni to use their resources :( I'll see if I can't find it elsewhere...

Edit 2: Found it :)

I will go through my library and see what I can find for you!

Boom: Hypervitminosis D in Green Iguanas

Double boom:<279::AID-ZOO7>3.0.CO;2-8/abstract
(A peer reviewed study on chameleons specifically is quite rare)
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