3 Types of UVB Bulbs For Bearded Dragons (we only recommend one!)

By Tim Steward
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3 types of uv bulbs for bearded dragons title card

There are two types of light that your bearded dragon needs: heat and UVB.

A basking bulb and fixture creates heat and aids in digestion. A UVB bulb simulates the UVB rays of the sun and aids in several other critical biological functions.

Your bearded dragon needs both!

We covered the five types of bulbs you can use for a basking bulb here. Now, let’s look at the three choices you have for a UVB bulb in your bearded dragon’s enclosure.

UVB bulb
Our UV bulb and light hood

What’s the Best Type of UVB Bulb For a Bearded Dragon?

The best type of UVB bulb to use for bearded dragons is a linear fluorescent tube and fixture. This light should be made specifically for reptiles and extend the length of their enclosure. A high output 10.0 UVB (aka HO 10%) provides the correct intensity UVB light for bearded dragons.

A standard linear UVB bulb and traditional light hood/fixture is the tried and true option. It works the best, is the most reliable, and is the easiest to set up and get right.

While two other options are sometimes used, they have some noteworthy drawbacks, and we do not recommend them.

That’s why in our bearded dragon’s home, we use this UVB fixture and this UVB bulb that you can pick up on Amazon. We have used this setup for many years and don’t plan to change any time soon!

Bulb Comparison

Avg. CostAdequate UVB?Easy To Use?Provides Heat?
CFL$10-$20NYN
MVB$50-$90YYY
Fluorescent Tube$50YNN

CFL (Compact Fluorescent Lamp) Bulbs

A CFL bulb is a coiled-up fluorescent light tube that fits in a standard light socket. You will sometimes see these advertised as being used in dual light domes and are occasionally sold that way.

A CFL bulb is the least expensive of the three types of bulb covered in this article and is sometimes preferred by bearded dragon owners on a budget.

CFL bulbs
Marketed as “mini UV” lights for reptiles, these are not a good solution!

We do not recommend this type of bulb for your dragon’s UVB needs because it’s entirely too small. Its size prevents it from giving off enough UVB light to cover the enclosure.

It does not provide adequate UVB levels across the entire enclosure and results in large swaths of your vivarium with no detectable UVB rays at all. This is a huge problem.

UVB is critical to your bearded dragon’s health (source). Its primary function (among many) is to allow your bearded dragon’s body to synthesize vitamin D. 

Without it, they will get very sick and eventually die.

So, as you can imagine, depriving your bearded dragon of UVB light in any area of its enclosure is a problem that should be avoided. An easy way to do this is to use lights that cover their entire home and not just one spot.

That means NOT using a CFL bulb!

MVB Bulbs

MVB (Mercury vapor bulbs) are “dual purpose” lights. They produce both heat and UVB and are often used as a single source for basking spot heat and UVB rays.

MVB bulb

Proponents of MVB bulbs make an excellent case that these high-output bulbs are the best overall option for bearded dragons. On paper, they are right. In practice, many times, they are not.

Let’s get this out of the way… MVB bulbs can provide both the right amount of heat and an exceptionally healthy level of UVB all from one bulb. They are the best overall option if set up correctly and closely monitored.

That’s why you see them used in reptile houses and zoos. But unless you have both the dedicated time and budget of a zoo, we don’t recommend you use them.

In order for an MVB bulb to work correctly, it must be precisely positioned over your bearded dragon’s basking spot. This placement is often well above your enclosure and requires special hardware to locate it there. 

It also requires a costly UVB meter and possibly a college class.

Why do I say that? Check out this guidance from Mega-Ray (the best manufacturer of MVB bulbs for reptiles):

100 Watt Bulb – MINIMUM distance setting of 12″ will produce approximately 150-200 microwatts per square centimeter(uW/cm2) of UVB and 900-1200uW/cm2 of UVA. MAXIMUM distance setting of 20″ will produce 50-70 microwatts per square centimeter (uW/cm2) of UVB.

And that’s just the start of their guidance on how to install the bulb. I don’t know about you, but I just want a pet, not a college-level science project!

It’s sooooooooo much easier to use a traditional linear fluorescent tube and basking lamp separately! And a heck of a lot less expensive!

If you are raising multiple reptiles and they are your hobby, an MVB bulb would be fun to figure out. If you don’t want to make things more complicated or expensive than needed, skip the MVB.

Linear Fluorescent Tubes

We believe the best way to get your lights set up correctly is to have separate basking and UVB bulbs. 

That allows you to adjust them independently of each other and makes setting up your beardie’s home fairly simple.

UVB light

“Linear Fluorescent Tube” is a fancy way of describing pretty much every fluorescent light you’ve ever seen. It’s a long tube. You probably have them overhead at work, over your workbench at home, or somewhere in your kitchen.

But you can’t just grab a bulb from your kitchen when using this type of bulb for your beardie’s UVB needs.

Instead, you’ll want to get a high output, 10% UVB (aka 10.0) bulb explicitly made for reptiles. We’ve always used this one by Zoo Med.

Your enclosure determines the length of the bulb and fixture. How big should your enclosure be? Check out our complete guide here.

If your beardie’s tank is 36″ wide, get a 36″(ish) wide fixture. If 48″, then 48″(ish). You won’t find exact matches, but get as close as possible. Here are the two we most commonly recommend.

Fixture for 36″ wide enclosure on Amazon.

Fixture for 48″ wide enclosure on Amazon.

If you place the fixture above the tank with nothing more than the screen top in the way, you will provide adequate UVB across the entire tank—some folks like to mount this fixture inside the tank as well. Either way works.

As with your basking bulb, change your UVB bulbs once every six months as the amount of UVB decays over time. The amount of light coming from a UVB bulb does not correlate with the amount of UVB. 

Do NOT use the UVB bulb until it burns out! Change it before that. Every six months!

The Verdict

Getting your UVB bulb correct (type, size, and placement) is essential for all of the reasons stated above, as well as one more…

The health issues created by lack of UVB light accumulate slowly. Diseases like MBD (metabolic bone disease) are crippling, painful, and irreversible. You won’t know your beardie is sick until it’s too late!

The best insurance against those types of diseases is to use the correct type of lights and change them regularly.

Further Reading and Sources

Bearded Dragon Husbandry

Vitamin D3 and UV Exposure

Vitamin D and Skeletal Development of Young Bearded Dragons with Different UV Exposure Levels.

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4 thoughts on “3 Types of UVB Bulbs For Bearded Dragons (we only recommend one!)”

    • It’s definitely possible, but I’d get a UV meter and measure to make sure. As a note, the right size fixture and bulb will cost about half or even less than half the cost of a UV meter. Just use the right thing to start with.

      Reply
  1. When we switched from a really small UV bulb to one that spans the length of the tank, our bearded dragon got way more colorful! It was really weird, but I guess the light made a big difference.

    Reply
    • That’s a great sign that you didn’t have enough UV before. It’s amazing how much more color they get and how much better condition their scales are in when they have the right amount of UV!

      Reply

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