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How to properly utilize supplements for your reptiles, amphibians and arachnids

How to properly utilize supplements for your reptiles, amphibians and arachnids

Most Reptile Keepers Are NOT Using Reptile Supplements Correctly

Written by Mariah Healey,

It’s fairly common knowledge that if you have a pet reptile, you need to be giving them dietary supplements (especially calcium) on their meals. This helps compensate for the natural deficiencies of the foods they’re eating in captivity and make sure they have all the nutrients they need to be healthy. But simply having supplements on hand because someone at the pet store or on the internet told you that you need them is not the same as knowing how to use them — and this is a very common problem among both new and more experienced reptile owners!

Expiration dates?

Supplements for non-insect foods?

Types of vitamin A?


If one or all of the above topics makes you go, “wait, that’s a thing??” the good news is that you’re far from alone. Here are four of the most common mistakes that reptile keepers make when using supplements to augment their pet’s diet, and what you need to know:

Mistake #1: Letting Supplements Expire

Did you know that vitamin supplements have an expiration date? Once opened, contact with the oxygen in fresh air causes them to start degrading, and they degrade even faster if exposed to exposed to warm temperatures. For humans, a lot of supplement pills are protected by encapsulation, as well as being packaged in opaque jars. But while reptile supplements are always packaged in opaque jars or pouches, they’re kept in powder form, which provides no protection against contact with oxygen.

How often should you replace your reptile’s vitamin supplements, then? If you keep them in a cool, dry place with the lid or package sealed shut when not in use, then you can reasonably expect them to last about a year before losing potency. If you tend to keep them in a warm room and/or have a habit of leaving the container open, though, you might want to replace your supplements every 6 months instead as a precaution. (Calcium supplements containing vitamin D3 should be treated as vitamin supplements.)

How long do calcium supplements last? Minerals are much less vulnerable to degradation, which means that if you’re using a pure calcium or multi-mineral supplement (ex: Arcadia CalciumPro Mg, Miner-All Outdoor), you don’t have to replace it before you run out. Of course, that’s not an excuse for leaving the container open all the time, especially in a humid environment.

Just like you should be marking your UVB lamp’s start date, use a permanent marker to write the date of opening on your vitamin-containing supplements and replace every 12 months to maintain effectiveness.

Mistake #2: Not Dusting Salads

Bugs aren’t the only reptile food that generally have a low calcium to phosphorus (Ca:P) ratio. If you have an herbivorous or omnivorous reptile that eats plates of greens on a regular basis, you should be dusting that salad with a bit of calcium. Why? Because the greens in the wild generally come from soils with a higher calcium content than on human farms, which means that the resulting plants have a higher calcium content as well. Furthermore, greens which have been bred for human palatability tend to be less nutrient-dense in general.

I like using Repashy Superveggie because it contains flower and superfood powders as well as calcium for extra nutrition (boosts palatability too), but a plain calcium powder will also do the job just fine.

Mistake #3: Using the Wrong Form of Vitamin A

Symptoms of vitamin A deficiency are nothing to joke about. In chameleons, for example, hypovitaminosis A can result in stunted growth, metabolic bone disease, tail necrosis, swollen lips/eyes, edema, spinal deformity, poor coordination, weak grip, respiratory infections, and/or loss of appetite.

If you have an omnivorous or carnivorous/insectivorous reptile, you should be using a vitamin supplement that contains pre-formed vitamin A (a.k.a. retinol), not carotenoids. Carotenoids are sometimes touted as “safer” than supplements containing retinol, since they allow a reptile’s body to make as much vitamin A as it needs at a given moment, similar to how reptiles use UVB to make their own vitamin D. However, non-herbivorous reptiles may not be able to efficiently convert carotenoids into retinol, which means that it’s important to make sure they’re getting enough actual retinol in their diet.

If you have an herbivorous reptile using a vitamin supplement which uses carotenoids to supply “vitamin A,” you should have nothing to worry about.

Common reptile multivitamins which contain retinol:

Common reptile multivitamins which use carotenoids instead of retinol:

Mistake #4: Not Gutloading

If you watch feeder insects for a bit after dusting them with supplement powder, you’ll notice that the powder doesn’t stick very well. It gradually falls off with the bugs’ movements, and much of the rest gets deliberately cleaned off by the insect itself. Supplement powder dusted on salad greens is “stickier,” but unless you’re tossing the greens in supplement powder rather than just sprinkling it on top, dosage depends on whether your pet actually eats the greens with supplement on them. So what’s a sure-fire way to make sure your pet is definitely getting extra nutrients?


You’ve probably heard of gutloading by now, but there’s a good chance that you don’t actually know what it means. Gutloading is not simply the practice of giving feeder insects a good diet and keeping them hydrated; gutloading is the practice of giving feeder insects a concentrated, plant-based diet of nutrient-rich foods for 2-3 days prior to feeding day. Normal insect feed is designed to help feeder insects breed and grow, while gutload formulas usually have a much lower protein content and are designed to boost a feeder insect’s nutritional value by “loading” its digestive tract with partially-digested superfoods.

Gutload formulas you can use include Repashy Superload, Arcadia InsectFuel, and Bio Dude Bug Grub.


If you’ve made it to the end of this article, pat yourself on the back! You are now a more capable reptile keeper with a better understanding of reptile nutrition and how to use the supplements available to you effectively. Here’s a quick summary to help you remember it all:

  • Replace your reptile’s vitamin-containing supplements every 12 months and be sure to store them properly in order to maintain potency.
  • All salads should be lightly dusted with calcium powder to correct the vegetables’ Ca:P balance.
  • Use retinol (pre-formed vitamin A) for carnivores and omnivores, and use carotenoids for herbivores.
  • Always gutload feeder insects with a high-quality gutload formula 2-3 days before mealtime.


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