Do Leopard Geckos Need D3?

Just like most of anything that’s living on this planet, leopard geckos need the right nutrients in their body in order to survive.  Some species of animals might need these nutrients a little less while others might need them a little more.  But, when it comes to leopard geckos and their nutritional needs, not having enough of them can be the difference between life and death.  Let’s go deeper.

Do leopard geckos need D3?  Yes, they do need it.  D3 is what helps break down and absorb calcium in their body, and calcium is what helps them grow.  How much D3 your leopard gecko receives will depend greatly on how old they are.

If there are two things that matter the most when it comes to a leopard geckos diet, then calcium and D3 would be at the top of the list.  Not because they are any healthier than other vitamins and supplements, but because they are literally the two main things that help your gecko’s bones grow and maintain throughout the duration of their life.  With that said, let’s see what else we can learn about the supplement D3.

How Is D3 Supplemented?

There are two ways to supplement your leopard gecko with D3 and that’s through their diet with a powder-based substance and also through a small light that shines over top of them called UVB.  Is one any better than the other?  Absolutely not.  It just all comes down to what you personally prefer for your leopard gecko.

While I use powder with my leopard gecko, I also recommend using a UVB light as well.  This is because each leopard gecko will behave differently to each method of supplementation.  For example, while others have seen great success using a UVB light, others have had trouble getting their leopard gecko to even come out of their hide long enough to be exposed to it to get their proper supplementation.

The same goes for those who have tried powder as well.  Leopard geckos can be picky eaters, so sometimes they won’t even touch their food if there is calcium and D3 dusted all over it.  So, In order for you to find out what works the best for you and your gecko, I suggest picking the method of supplementation of your choice and then experimenting from there.  Sometimes figuring out what your leopard gecko likes will take some trial and error, but eventually, you’ll get there.

Also, I think UVB lights actually look pretty cool while in the tank, so that’s one bonus to using them.  As for the people who’d rather just supplement through powder, then I recommend Repashy.  It’s what I currently use and absolutely love.

I just put a little bit of it in a plastic baggy alongside some feeder insects, shake it up, and then feed them to my gecko.  It’s a really simple and fairly quick process.

When to Supplement with D3

Just like calcium, you’ll want to supplement your leopard gecko with D3 every single time you feed them.  If you own an ” all-in-one” supplement like me, then they will be getting all of their needs in one powder.  But, if you have UVB, you will need to buy a separate container of calcium without D3 and also another separate container for their multi-vitamin as well.

Because I like to keep it simple and also because my leopard gecko prefers powder over UVB, the all-in-one supplement is perfect for my needs.  But, again, what you choose will be perfectly fine.

Also, keep in mind that even though all leopard geckos need D3, they will not all consume the same amount.  This is simply because depending on their age, they will all have different amounts that they eat at a time.  And if every meal is dusted with D3, then that obviously means that the leopard geckos who eat more will be taking in more than the leopard geckos who don’t eat as much.

As for my UVB users, you’ll want your light set on a 12 hour on and off timer.  This means for 12 hours you’ll want your UVB light on and for another 12, you’ll want it off.  Leopard geckos usually wake up around 7:00 PM but will sometimes pop out to soak up some D3, so setting your timer to about 7:00 AM to 7:00 PM should work just great.

The UVB is meant to mimic the sun, so it’s alright to have it off at night while they’re active.  They have senses that they’ve developed while being in the wild that allow them to be able to easily maneuver throughout the night.

Does D3 Go in the Tank like Calcium?

While D3 is a huge part of their diet, it shouldn’t be accessible to them at all times like calcium should be.  Many people make the mistake of putting a calcium + D3 mixture inside of their tank for them to lick out of whenever they feel that they need it, but the only problem with that is that this can actually cause D3 toxicity, which is what happens when they get too much D3.

So, whenever putting calcium in the tank, make sure it doesn’t have D3 in it.  For a calcium supplement without D3, Repti Calcium is a good choice. As long as your leopard gecko is getting their D3 supplementation through their UVB light or when fed, then they don’t need any more than that.

Also, anytime you’re choosing a supplement, make sure you read the description on the bottle to ensure that you’re not getting the wrong thing.  It can be easy to accidentally get the wrong bottle of what you need, so definitely keep an eye out for that.

Overdoing It with D3

Although D3 toxicity is rare, it does happen.  How much D3 it takes for them to get to this point, nobody really knows, but it’s best to only give it to them when either being supplemented with it with their insects or through UVB.  The reason why D3 is not recommended to be put in their tank like calcium should be is because like stated above, there is a small chance that D3 toxicity can occur.  But even then, it is pretty unlikely.

There have been people who have made the mistake of putting a calcium + D3 mix into their tank when first getting their leopard gecko and while some have had great luck with nothing happening to their gecko, others haven’t, so it’s not worth the risk.

To give you an idea of what you could be faced with if your leopard gecko ever consumes way too much D3, then look at some of the symptoms here:

  • Weight Loss
  • Constipation
  • Fatigue
  • Increased Thirst
  • Increased Urination

Unfortunately, whenever this happens, most owners leopard geckos just don’t make it.  The overload of D3 can cause their little kidneys to fail and eventually they’ll start to slowly shut down until they eventually pass away.

This is why it’s always good to monitor exactly how much D3 you’re giving them and making sure you’re not supplementing them with it through UVB and through powder at the same time.  A lot of mistakes can happen as a beginner leopard gecko owner, so something like that happening would definitely not be something that hasn’t been done before.

Maintaining a Schedule

To make sure your leopard gecko is being supplemented on a regular basis, it’s best to write down a schedule or keep a log of when you’re feeding them so that you don’t forget when and what times you should be giving them what they need.

Although you don’t have to be as strict when it comes to feeding and supplementing adult leopard geckos seeing as they don’t eat as much, you will have to be when it comes to leopard geckos that are anywhere from 0-6 months in age.

The reason for this is because during this time they’re doing a lot of growing, so it’s very important to make sure they’re getting the right amount of what they need every single day in order for them to get bigger without any problems.

Back when my leopard gecko was a baby, I used to always feed them calcium + D3 on the weekdays and then his vitamins on the weekends, but as he’s gotten older, I’ve just converted to using the supplement I’m using now that just gives him everything he needs in one powder.

And even though you can go the UVB route and buy additional calcium and multivitamin bottles, I would definitely recommend that anybody who is new to being a leopard gecko owner just use the all-in-one supplements as this can be a lot easier to keep track of and you won’t have to worry as much about forgetting supplements or trying to keep up with and remember a feeding schedule.

This isn’t a problem for most, but some people have a hard time doing that when first starting off.  So, if you’re somebody who’s like that, then just focusing on one form of supplementation is the smartest thing to do.

If you do that, feeding them on time every day should be a breeze.

Do Feeder Insects Carry D3?

According to this source and aside from dusting with D3, I don’t think that feeder insects naturally carry a whole lot of it unless they are exposed to UVB, and even then, they still wouldn’t be sufficient enough in providing your leopard gecko with the amounts that they need.

If that were the case, then that would definitely be awesome because then we wouldn’t have to dust our feeders anymore.  But, unfortunately, it’s not.  From what we have available to us so far, UVB and powder seem to be the best ways of providing our leopard geckos with D3, but maybe in the future, we can somehow come up with certain fruits that are already packed with D3 so that we won’t have to dust or use UVB anymore.

And although feeder insects don’t carry D3, they do carry a ton of other vitamins that are beneficial to your leopard gecko, especially when gut loaded.  These vitamins will depend on what type of fruit you are loading them with.  But, if we’re talking about grapes, for example, according to this source, here are some of the vitamins and minerals that you can expect your leopard gecko to take in if you’ve given them feeders that have been loaded with them:

  • Vitamin C
  • Vitamin K
  • Vitamin B1
  • Vitamin B2
  • Vitamin B6
  • Copper
  • Potassium

And that’s just with one fruit, imagine all the other vitamins they might be getting from other fruits.  On top of that, they’re also getting vitamins from the multivitamin supplement that you’re giving them as well.  So, although feeder insects don’t carry much D3, they are still very nutritious for your leopard gecko.

How They Supplement in the Wild

Considering all the effort we put in to make sure that our leopard geckos are receiving the right vitamins and nutrients that they need, it sometimes can be a wonder on exactly how they supplement themselves in the wild with all of these things without our help.

Like stated above, UVB lights are meant to mimic what the sun does, so that tells us that when in the wild, they get all of their D3 needs from the sun.  This is why it’s healthy to have them on a day/night cycle instead of all over the place when it comes to how their UVB light is set.

As for their hydration needs, they get most of that from the prey that they eat.  The habitat they live in is very dry, so the fact that they’re able to satisfy their thirst from other dry animals tells you just how much water they actually require in order to survive.

The prey you can expect to see them eat in the wild will range anywhere from centipedes all the way down to other lizards.  They’ll even eat another leopard gecko for hydration if they need to, they definitely do not discriminate when it comes to this.

As for their food, you would think that would be eating the same type of insects that we feed them while in captivity, but again, they like to eat things like lizards and sometimes even scorpions.  Food can be scarce in the wild, so whatever they can get their hands on, they’ll take.

Leopard geckos are on a race against time when looking for their supplementation when out in the wild, but somehow, they manage to pull it off successfully for many years.  To get a deeper look at what life is like for leopard geckos in the wild, I recommend checking out this article here that I wrote.  It goes more into detail on how they supplement as well as other things that they go through when not in captivity.

Why They Are Supplemented More When Younger

The main and only reason why leopard geckos require more D3 when they’re younger is simply for the fact that they need it to grow.  As leopard geckos become adults, they will still require both D3 and calcium for as long as they live to keep their bones strong, but consumption will go down pretty significantly from the time in which their hatchlings all the way up until the time when they reach full adulthood where they eventually stop growing as much.

D3 isn’t what makes them grow, but it helps absorb the stuff that does actually make them grow, so in a way, it kind of does indirectly help them grow.  But of course, it wouldn’t be effective without the calcium to go along with it.

As they get older, their supplementation intake will drop from every day to only receiving it 1 to 2 times per day and will stay like this for the rest of their lives.  Some leopard geckos eat a lot less while others eat a lot more, but even then, you can still expect your own individual leopard gecko to not be eating as much as adults as they were when they were babies and juveniles.

Supplementation is how they thrive and is never something that will ever be able to leave their diet.

How Much Calcium Should Go with D3?

During feeding time, the amount of D3 and calcium you give your leopard gecko should be the same, but because calcium is what makes their bones grow, it’s recommended to always have a bowl of it without D3 inside of their tank.

You can overdo it when it comes to the amount of D3 you give them, but with calcium, it’s much harder.  Their bodies aren’t very good at functioning with too little calcium in their system, but they are good at getting rid of too much calcium that they may not necessarily need, so this is why it’s okay to have a bowl of it in their tank at all times.

Some may wonder why they need extra calcium if they’re already being fed it, but this is just to make sure they have access too in just in case they feel like they need a little more than what we have to offer them.  When it comes to how much to consume and when to stop, leopard geckos are actually really smart in disciplining themselves to not overindulge.

Although leopard geckos can become ill from too much calcium, it does take having a lot of it in their system for them to actually get to that point.  It’s far easier for this to happen with D3, so that’s why it’s not supposed to be put in the tank alongside the calcium.

That’s why I recommend Repti-Calcium without D3 if you’re like me and use a multi-supplement like Repashy.  Repashy is great to dust your feeders with and gives your leopard gecko the vitamins that they need, but it is not what I would recommend being put in their tank by itself because it also contains D3 as well.  So for that, Repti-Calcium is great because they do have a version with calcium only without the extra vitamins and D3.

Analyzing the Great “UVB vs Synthetic D3” Debate

Like stated above, whichever way you decide to supplement your leopard gecko with D3 is fine, but just like most things in the leopard gecko community, there is, of course, a great debate over which one is better than the next, when actually most of the arguments just simply come down to which way is more ethical or not.

Both ways of supplementing do have their advantages and disadvantages, but I wouldn’t go as far as to say one way is better than the other because the advantages and disadvantages are pretty insignificant.

For example, some say that the advantage of using UVB over synthetic D3 is simply for the fact that the leopard geckos will be exposed to more light and won’t be wasting away living a life full of darkness and misery.

But, when it comes to most people that I’ve seen who own leopard geckos, a lot of them have their tank set up in a room that gets plenty of natural light from the sun and have had no issues with their leopard gecko doing it this way at all.

While I do agree that leopard geckos should receive sunlight on a daily basis, I don’t necessarily think that that reason alone is strong enough to not use synthetic D3 and go with UVB instead.  UVB is more natural, but even then it’s still not as natural as getting D3 from the sun, so in my opinion, no one way has enough evidence that shows whether or not they are more superior than the other.

As long as you don’t have your leopard gecko trapped somewhere in an overly dark basement, then I think using synthetic D3 is just fine.  From what I’ve personally seen, far more people use synthetic d3 anyway just for the fact that it is more efficient to use.

With certain brands out there that provide all your leopard gecko’s nutritional needs in one powder, more and more people are finding it to be more cost efficient and less of a hassle using substances like these instead of having to worry about getting all your leopard gecko’s supplements and vitamins separately.

With UVB, that is usually the case.  In addition to the light, you’ll then have to buy calcium and then buy a multivitamin just to provide them with what they could be getting with one bottle of a calcium + D3 + multivitamin mix.

I’ve used both and will even often recommend each way because I think that they’re both great ways for supplementing, but as far as one being better or less harmful than the other one, I don’t think anyone has any real solid reason as to why you absolutely should not go with one over the next.  Just pick the one that you think would be more suitable for you and then go from there.


Because supplementation can be quite a difficult thing to grasp when first starting out, I figured I’d write this article so that I could hopefully help those who may be confused with how everything works when it comes to it.

In addition to this article, I also wrote one about calcium because of the importance of that supplement as well.  If you’d like to check that one out, then I recommend clicking here to go to the page.  I touch base on both in each article, but for the ones that are strictly directed towards one supplement, I go into a lot more detail so that you guys can get a full understanding of it all.

If there’s anything that you feel like I missed or if you have any further questions, then feel free to let me know and I will get to them as soon as I can.  Because supplements are so important in a leopard gecko’s diet, I don’t want anybody to be confused when it comes to them because confusion usually causes new leopard gecko owners to make mistakes that put their gecko’s life at risk.

If you ever happen to get confused, please come back to this article and read it again so that you can know exactly what to do and what not to do when supplementing your leopard gecko with D3, vitamins, and calcium.

All three are critical to their health and if they’re not supplemented the right way, many bad things can happen to your leopard gecko.

I’m Devin Nunn, an average joe that just so happens to have a deep love and passion for everything to do with reptiles. Because taking care of them for the vast majority of my life wasn’t fulfilling enough, I decided to begin educating others about them through my articles. read more...