Iguana Macro and Micro Nutrients


Good nutrition, combined with the other essential elements of utilizing that nutrition (like proper heat, sunlight and a roomy enclosure), is the basis for all stages of an iguana’s proper growth and good health.

Nutrition can be described as a balance of vitamins, minerals (including trace minerals), amino acids, enzymes and micronutrients that all together support the proper function of internal organs, skeletal growth, muscle, tissue and nerve maintenance, and normal body metabolism.

In iguanas, as well as other ectothermic poikilotherms (animals whose bodies don’t generate internal heat but depend on external sources of heat for internal body function), research on nutritional requirements are limited and have only been officially recorded in the last few years. Much of the information we (and veterinarians) rely on is based on trial and error, observation, and experimentation.

One thing we know for sure is that an iguana that fails to thrive is missing an important component in his or her daily life. It could be lack of proper heating – day and night, poor enclosure conditions, stress (very important!) or inadequate diet.

Last month we talked about proper renal (kidney) and liver function because the way iguana’s process their food puts special demands on these organs. An iguana’s reduced metabolic rate requires proper heating and cooling (temperature gradients). Less than ideal conditions will impair the iguana’s ability to absorb and process the essential nutrients. As the iguana grows, these less than ideal conditions begin the slow process of damaging these vital filtering organs so that the animal’s life span and ability to thrive are forever compromised.

These very nutrients, fed under less than ideal conditions and in a partially or unprocessed form, can create the insoluable (uncapable of dissolving) salts and high acidic content that damages delicate tissues in the kidneys and liver. This damage will continue, especially in the kidneys, if the problems in husbandry and diet are not corrected.

So just feeding a well-balanced diet is not the whole answer, it is only a part of the puzzle. A good diet must be combined with correct temperature gradients and exposure to the sun (UV light waves) so that vitamins, minerals, and the other essential micronutrients are properly manufactured and metabolized.

Most authorities agree that most necessary vitamins and minerals are available through a good diet with sun exposure and that supplementation is really not necessary. Overzealous application of crude calcium/vitamin powder from the pet store can actually do more harm than good.

The image of a young iguana being offered a plate of greens with white powder liberally sprinkled on top is a sad one. It is no wonder that the small iguana doesn’t have an appetite for such a meal. It certainly doesn’t look, smell or taste like something good to eat.

Yes, an immature iguana probably can use that extra calcium while in that first year or two of rapid growth but there are many other ways to administer it. Look for a complete liquid vitamin supplement with calcium and no phosphorus. Most reptile vitamin powders use calcium carbonate and dicalcium phosphate along with Vitamin D. Iguana diets never need the addition of powdered phosphorous as most vegetables have both phosphorus and potassium in adequate or high levels. Keeping the diet at 2:1 calcium to phosphorous is difficult if not impossible if you are supplementing with dicalcium phosphate.

If your iguana is under two years old, supplement twice weekly with a pinch of calcium citrate (finely grind up a tablet) and never use a vitamin supplement with phosphorus or Vitamin D added. The addition of Vitamin D to reptile vitamin/mineral supplements assumes the purchaser is not giving their iguana the proper exposure to UV lighting or sunlight. This is how vitamin overdosing (Hypervitamintosis) occurs. Oversupplementing crude Vitamin D causes the body to process too much blood calcium which is not expelled by the body but stored in the organs, tissues, muscles, kidneys and other internal organs causing a mineralization of the tissues. With an adequate amount of calcium and exposure to the proper ultraviolet light waves that metabolize natural Vitamin D, any extra calcium ingested will be expelled with the urates and feces.

Using pet store powders (or vitamin sprays which are just as bad) will not help you to maintain a proper calcium/phosphorus ratio. And… Always remember that giving crude supplements does not make up for an inadequate diet.


If your iguana is doing well and seems perfectly healthy and happy, you may choose to get a blood test done so you have baseline information on hand for future use. Knowing what is a normal value can help you and the veterinarian understand whether your iguana’s system is undergoing a serious change when blood is drawn and tested during an illness.

Blood tests can be expensive so call your vet first and ask what it would cost to do a baseline blood test. You will probably have to explain why you want it. Hopefully, a reptile vet will understand and appreciate that you are planning ahead for possible problems when your iguana gets older. If your vet is reticent, you might inquire if there is a lab in the area that could perform the blood draw and testing.

Checking with a lab in your area might save you money also. If you live in a large urban center, you might find a lab that could perform the tests you need. Reptile blood is handled in the same way avian (bird) blood is processed. However, always ask what they use as an anti-coagulant. Heparin (lithium heparin) is preferred over EDTA as EDTA may affect the form and structure of the cells.

You would want both hematology and blood chemistry done. Hematology looks at the red and white blood cell count, the hemoglobin and lymphocytes while blood chemistry shows what the calcium, phosphorus, potassium and other biochemical levels are.

Having this information before your iguana shows any signs of illness will help you and your vet be clear about what is happening and will help you understand more fully what the vet is talking about when he explains the results of a blood test done when your iguana is sick.

Any veterinarian who suspects organ failure will do a series of blood tests to determine what is going wrong. As we have discussed in the past, the symptoms for liver or kidney disease can be hard to define. Having a normal blood value chart can help to eliminate some of the questions. See (PRINTED NEWSLETTER) for the blood values from a normal iguana. If you get your iguana’s blood values charted, you can compare them to this iguana’s values.

As Editor-in-Chief at MyPetReptiles.com, I bring a decade's worth of experience as a reptile enthusiast and breeder. From nurturing bearded dragons to understanding the nuances of chameleons, I'm deeply passionate about sharing my journey and expertise. My mission is to empower fellow reptile lovers, providing them with valuable insights to ensure the best care for their captivating pets. Here at MyPetReptiles.com, we believe in transforming knowledge into shared joy for our global community of reptile owners.

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