About HOX

If you’ve had bariatric surgery, you may be facing a risk to your kidney health without even knowing it.
You may already know that bariatric surgery comes with benefits and drawbacks. But a potential downside you may not be aware of is high oxalate, or hyperoxaluria (HOX), a common after-effect of bariatric surgery.


Oxalate is a compound found in many plants, including fruits and vegetables that we eat every day. While some oxalate in the body is normal, bariatric surgery can lead to high levels of oxalate in the body, called hyperoxaluria (HOX), a common complication of bariatric surgery.

For some people, oxalate can collect in the kidneys and form recurring kidney stones. Over time, this excess oxalate can be damaging to your long-term kidney health — not to mention the pain, incontinence, and uncertainty that comes with recurring kidney stones.


High levels of oxalate cannot be broken down by the human body. When the levels are too high, the oxalate collects in the kidneys and can form kidney stones.

Oxalate collecting within the kidney

Oxalate kidney stone entering ureter

There are no approved therapies for HOX. But the SYNHOX Study may be an option for you. This phase 1 study is evaluating the safety of an oral treatment designed to potentially reduce oxalate in the body and potentially prevent kidney stones in people who have undergone bariatric surgery.