Beardies First

Can a Bearded Dragon Have Too Much UVB?

Bearded dragons should get UVB ray exposure every day to help maintain their health. However, can a bearded dragon have too much UVB?

can a bearded dragon have too much uvb

Unfortunately, bearded dragons can get too much UVB and be overexposed. These reptiles will see UV as required biologically. Overexposure, however, often happens if the animal cannot dodge or move away from the source of UVB rays. Proper setup of your beardie’s enclosure is essential to avoid overexposure.

Importance of UVB to Bearded Dragons

Bearded dragons are reptiles that live in the desert, which means they have already adapted to the harsh environment. The presence of UVB rays can regulate vitamin D3 and its absorption and production in the skin.

Vitamin D3 aids in the use of phosphorous and calcium in the body of a bearded dragon. Calcium is essential for muscle contraction, bone development in baby dragons, and egg development and reproductive health in female beardies.

The rays of the sun are also critical for food breakdown into nutrients. Adequate amounts of sunlight can help in blood circulation, growth, healthy metabolism, and keeping the beardie’s body warm.

Take note that vitamin D3 and calcium present in your dragon’s body will not be able to synthesize if there are insufficient UVB rays. This is why this process requires direct sunlight exposure. Meanwhile, low levels of calcium may result in MBD or Metabolic Bone Disease.

UVB shine on beard dragon

How Much UVB Do Bearded Dragons Need?

Exposure to UVB rays for 12 to 14 hours is already enough for your bearded dragon to survive and stay healthy.

Risks of Too Much UVB for Bearded Dragons

While bearded dragons do need UVB, too much exposure to it may cause some negative effects on their body. Below are the most common side effects of excessive UVB exposure to your beardie:


Too much exposure to UVB may result in increased calcium levels in the body of your bearded dragon. This increase in calcium levels may lead to the formation of higher amounts of calcium deposits in your beardie’s kidneys, resulting in hyperthyroidism disease.


Excessive exposure to the radiation of natural sunlight will cause callouses, lesions, and skin thickening in your bearded dragon. You might also notice some physical changes around your beardie’s nostrils or nares and the mouth. Hyperkeratosis can later affect the way your bearded dragon breathes and eats.


Calcification of the vital tissues in the body of your bearded dragon may also occur after too much exposure to UVB. You may also notice deformity in the physical appearance of your dragon. The brittle bone disease may also occur. Unfortunately, kidney failure or even death may occur as a result of hyperparathyroidism.

Photo-Kerato Conjunctivitis

Photo-Kerato Conjunctivitis is a condition that occurs when your bearded dragon has been exposed to too much UVB. This condition can cause the eyes to become red and swell.

The good news is that this is only a temporary condition and will just fade over time. You just need to eliminate the source of the UVB rays for several hours daily to address this situation.

Common Causes of Too Much UVB Exposure in Bearded Dragons

There are several common reasons behind too much exposure to UVB in beardies, and these include the following:

  • Bearded dragons need cool-off zones and hiding spots to avoid excessive UVB rays. The reptiles may end up overstaying in the basking area if there are no hiding spots installed in the tank.
  • Improper lamp positioning will also raise the output levels of UVB. Typically, incorrect positioning happens if the lamp is positioned on either side of the tank instead of overhead.
  • Leaving the tank’s lights at night is another common cause of excessive UVB exposure.
  • Poor maintenance of the environment inside the tank is most of the time the main reason behind too much UVB exposure. For example, installing a UVB lamp near your beardie will cause two times as many rays to hit the enclosure.
  • Poor quality or substandard lamps that don’t match the tank’s size will cause overheating. Take note that low-quality bulbs give off more UVB rays compared to high-quality and recommended lamps.

How to Prevent Too Much UVB in Bearded Dragons

There are several simple ways you can follow to keep your bearded dragon protected from too much UVB exposure.

  • Ensure proper positioning of UVB heaters and bulbs.
  • Correct positioning of the UV bulb gradient and lamp and maintaining the right level of temperature will let your bearded dragon self-regulate inside the tank. But you might want to avoid coil UVB bulbs because these are often too strong for the reptiles. The ideal UVB exposure for bearded dragons is 10.0.
  • Follow the suggested photoperiod night and day cycle for bearded dragons in captivity to match the natural wild environment.
  • The right photoperiod schedule can create the ideal resting and basking schedule. You might want to improvise your beardie’s tank with timers to help with the on and off switching of lights.
  • Designate hideouts inside the tank.
  • Beardies like hangouts. If you haven’t installed one yet, make sure you add a wooden hideout. Hideouts are recommended for both the mental and physical health of your pet. These hideouts also help regulate the body temperature of your pet after it gets exposed to too much UVB.
  • Buy quality lamps suitable for the fixture.
  • Make sure the lamp you choose can produce around 125 to 150 watts for adult bearded dragons. Mercury vapor lamps are considered the best alternative lamps you can use for this purpose. These lamps can produce both UVB and UVA rays and are also durable. Make sure you also change the vapor bulbs after 6 months.

How Long Can Bearded Dragons Go Without UVB?

Bearded dragons will not be able to survive that long without exposure to UVB light. Most of the time, these reptiles can only last for a maximum of two days without UVB. As mentioned earlier, UVB serves as the source of vitamin D which has an important role to play in the absorption of calcium in the body. Poor calcium absorption results in several potential health concerns in bearded dragons.