Common Questions about Phosphate Binders

Provided by DaVita® Dietitians

Phosphorus is a mineral utilized by the body to build bones and teeth, to maintain proper pH balance and to transport oxygen to the body’s tissues. Phosphorus is necessary to maintain good health but high phosphorus levels can lead to heart disease and other complications when a person has chronic kidney disease (CKD) and is on dialysis. Phosphate binders are prescribed to dialysis patients to help prevent extra phosphorus from being absorbed from food into the bloodstream.

So what is a phosphate binder exactly?

A phosphate binder (also referred to as a phosphorus binder) is a pill your doctor has prescribed to control the amount of phosphorus in your blood. You likely are given one of the following common binders:

  • Renagel® / Renvela® / Fosrenol® (non-calcium-based binders)
  • Calcium Acetate® / Phoslyra®/Calphron® (calcium-based binders)
  • MagneBind® (magnesium-based binder)
  • Velphoro® / Auryxia® (Iron-based binders)

Some binders work like magnets, while others work like sponges. They bind to or soak up phosphorus in food during digestion. Then the binders and phosphorus are removed through bowel movements. If a binder is not taken, phosphorus can accumulate in the blood.

There are three different types of phosphate binders: aluminum-based, calcium-based and aluminum-free/calcium-free. Calcium-based and aluminum-free/calcium-free are the most commonly used phosphate binders. Your doctor will determine which type of phosphate binder is best for you.

Why do I need a phosphate binder?

Phosphorus is a very common mineral and can be found in many processed foods and cola drinks. It is so prevalent that phosphorus intake from food additives alone in the American diet has increased from 500 mg/day in the 1990s to more than 1,000 mg/day. As more phosphates are used in the food supply, this number continues to rise. Phosphorus from phosphate additives is absorbed almost 100 percent compared to naturally occurring phosphorus of which 40 to 60 percent is absorbed.

High phosphorus levels can cause:

  • Weak, brittle bones that break easily
  • Itchy skin and hard bumps under your skin
  • Damage to your heart, blood vessels and lungs

When do I take the phosphate binders?

Binders must be taken as prescribed by your physician. They are usually prescribed to be taken each time you eat meals, snacks or supplements.

What if I forget to take my phosphate binder?

Timing is everything: Be sure to take your binders when you eat food — the longer you wait, the less they work.

How many phosphate binders should I take?

Ask your doctor or dietitian to help fill-in these blanks:

Take ______ binder(s) with meals.

Take ______ binder(s) with snacks.

You may need extra binders if you eat high phosphorus foods or a larger meal.


Phosphorus is necessary for good health but too much can cause problems for people with kidney disease. When a kidney diet and sticking with your scheduled dialysis treatments isn’t enough, your doctor and renal dietitian will prescribe phosphate binders. By working with your doctor and taking binders with your meals, you can keep your phosphorus levels in check.