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How Long Can A Bearded Dragon Go Without UVB?

Are you a new bearded dragon owner wondering about the UVB for this pet?

Did your UVB light burn out, and now you need to know how long your beardy can survive before you pick up another?

Most lizards have evolved for a need to absorb the sun’s rays as part of their body’s function.

So, it’s essential to know how far your bearded dragon can go.

How long can a bearded dragon go without UVB?

A bearded dragon can go two days without UVB light. But, without Vitamin D, they can’t absorb calcium properly, which results in a whole host of diseases weakening the bones and body of your pet, resulting in death in the worst cases.

Read on for more details on how to care for your bearded dragon.

how long can a bearded dragon go without uvb

How Much UVB Does A Bearded Dragon Need?

A bearded dragon’s most common health problems tend to be related to calcium deficiency.

In nature, this doesn’t usually occur.

The difference: In the wild, they get a lot more sun.

Bearded dragons live in the Australian deserts naturally, so we need to keep their heat AND UVB exposure up for them to survive in captivity.

Specifically, bearded dragons need an output from the light of 8% – 10% UVB.

This specification should be marked on the bulb you use.

Don’t just assume all UVB will be enough.

With the right kind of bulb (see more below), ensure they’re exposed for long enough to get what they need.

We recommend at least 12 hours of exposure to UVB bulbs.

Up to 16 hours would work just fine as well.

The general rule of thumb is to leave the lights on for the day and then turn it off at night.

You may want to consider a timer, so you don’t forget to turn it on or off. This is especially true if you plan to take your bearded dragon on a road trip.

Note: This is the same idea you want to follow with your heat, as well.

Due to the high need for UVB, a beardy won’t survive long without it.

Two days is the longest you can let your pet go without UVB.

While it may live over this time, it’s right around two days when the damage starts to get done.

Vitamin D from the UVB is needed to absorb the calcium from its diet.

A lack of calcium can be recovered from, but too much deficiency could end up causing irreparable damage.

Should I Turn My Bearded Dragon Light Off At Night?

For sure! A bearded dragon needs to have a comfortable day-night cycle.

In the hot summer, the days are mostly light with a few hours of darkness and cool, so you should provide at least 6 hours of “night” when possible.

Technically, you could do this during any time of day, but it makes the most sense to align your bearded dragon’s cycle with your own.

When you wake up, turn on the lights and heat.

When you go to bed, turn it off.

If you find yourself being forgetful, you could also buy a timer switch to help give the reptile what it needs without forgetting. 

UVB Gear

To help keep your bearded dragon happy and healthy, you need to set yourself up with the correct UVB gear.

There are three things you may need:

  • UVB bulb
  • Lamps
  • Timers

This section will briefly discuss each and offer a few recommendations.

UVB Bulbs

First, UVB bulbs are the item you need for your tank.

You may already have light fixtures, lamps and get away with a timer, but you need UVB bulbs.

Some UVB bulbs also provide heat.

If this is the case, you need to ensure it doesn’t get too close to the bearded dragon.

This can cause burning in some cases.

There are different types of lighting for bearded dragons.

Although fluorescent lights may be preferred, the type doesn’t matter because they reach the whole tank easier.

The most critical requirement to watch for is the 8% – 10% UVB given off by the bulb.

This should be marked on the packaging.

Or get one made specifically for bearded dragons.

Here are a few we recommend:

Lamps/Light Fixtures

The lamps are only necessary if you don’t already have a system to use the UVB bulbs.

Many enclosures come with the ability to use fluorescent lighting.

If this is the case, you won’t need any additional lamps.

But if you don’t, you’ll need a way to provide light.

UVB should be spread throughout the tank, if possible.

At the very least, you need to have a bulb giving UVB in the basking spot.

When we talk about lamps, we don’t mean a desk lamp either.

It needs to be some kind of equipment to have a bulb inserted into and attached to the top of your pet’s enclosure.

Note: The lamps should be placed in the tank, not on the outside.

Glass and plastic block a lot of the radiation you want your pet to get.

These don’t have to cost a lot.

The Zilla Reflector Dome is attached anywhere and provides a spot with a UVB bulb.

Or you could go a little fancier and permanent by installing the Petsmore Light Fixture.

It costs a bit more, but once installed, all you need to do is change out the bulbs as they die.

The Zilla Tropical T8 is also a fluorescent fixture able to be installed and then switched out.

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Timers aren’t needed, but they do make your life easier.

Instead of risking forgetting to turn the light on in the morning, just set it on a timer and forget it.

They are as simple and affordable as this one on Amazon you set every night as you turn the lights off.

Other Ways To Avoid Calcium Deficiency

Despite a good UVB setup, you may still find your bearded dragon is deficient in its calcium.

With the correct amount of UVB, this is easy to fix.

Here are a few other ways to avoid or replenish calcium deficiency.

More Greens

An adult bearded dragon’s diet should consist of mostly greens, including fruits, veggies, and natural vegetation.

These greens, especially veggies, are much higher in calcium than most insects.

Check the diet for your pet and adjust to include more greens to help fix the imbalance.

Calcium-rich Insects

When you notice or have a vet diagnose your bearded dragon with low calcium, you should focus on feeding it insects high in calcium.

Supplements can help, but the food is the best way to get nutrients.

To this end, Dubia roaches make an excellent choice for food.

They do cost a little more, but they’re tasty to the reptiles and packed with good stuff for your pet. 

In fact, roaches are gut-loaded too!


Supplements should be a standard part of your pet’s diet.

Sprinkle some reptile supplements on every meal before they eat to help get more calcium and other nutrients.

Just remember, none of this matters if the UVB isn’t correct.

Without vitamin D, there isn’t any calcium absorbed.

We have a great review on supplements for bearded dragons if you’ve never used one before or are looking for better options.

Gut Loading

The better way to get supplements to your pet is through gut loading.

Gut loading boils down to feeding the insects a rich in nutrient food the day or two days before feeding the bugs to the beardy.

This puts more nutrients in the prey’s system in a way your bearded dragon can absorb more efficiently.

Fluker’s High Calcium Cricket Feed will get this done nicely.

For crickets, feed them less than a day beforehand.

Dubia roaches can go up to a couple of days before feeding to be gut-loaded.

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Now you know how long a bearded dragon can go without UVB.

Two days may not seem like much (and it’s not), but keep in mind how this lizard has evolved with a vital need for the Vitamin D it absorbs.

Protect your pet by keeping a handful of spare UVB bulbs so you don’t have to panic about your beardy’s UVB needs.

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