Why Men Form More Kidney Stones

Men form kidney stones at almost twice the rate of women, and hormones like testosterone and estrogen play a big role. In this blog, I break down why these differences exist, how hydration and diet factor in, and what men can do to lower their risk naturally.

Key Takeaways

• Men have nearly double the risk of kidney stones compared to women.

• Hormones like testosterone and estrogen directly influence kidney stone risk.

• Hydration, calcium levels, and creatinine also contribute to higher male risk.

• Proper hydration and diet adjustments can significantly reduce stone formation.

When people ask me whether men or women form more kidney stones, I can tell you the answer is pretty clear. Based on the most recent data, about 11% of men will form kidney stones compared to 6% of women. That's almost double!

Before I dug into the research, I probably would have said the rates were about the same. Honestly, it still feels that way sometimes. But after studying this deeply, I’ve learned that hormonal differences between men and women heavily influence stone formation risk.

When we talk about contributing factors, hormones can influence important elements like calcium levels, magnesium, oxalate synthesis, uric acid content, and even enzyme activity in our bodies. All of these pieces tie directly into kidney stone risk.

Let’s start by looking at the male side of things.

Testosterone, the primary male sex hormone, plays a major role. As testosterone levels increase, so does something called glycolic acid oxidase (GAO), an enzyme produced in the liver. GAO increases the body's ability to synthesize oxalate internally, rather than just through food sources.

This matters because more oxalate in the body equals a greater risk of forming kidney stones.

In one study, researchers supplemented subjects with dihydrotestosterone (DHT) for four weeks and found a 12.8 times increase in urinary oxalate excretion compared to a control group. That’s huge!

However, I do want to add a personal note here.
Despite my testosterone levels being very high for my age group, I haven’t had a kidney stone in over three years. I eat almost exclusively meat—going against mainstream advice—and my stone type is calcium oxalate.

So there’s clearly another factor at play here that the research hasn't fully uncovered yet. Take this information with a grain of salt.

Testosterone also impacts osteopontin, a protein that normally prevents crystallization of calcium and oxalate (and calcium and phosphate). Testosterone decreases the protective effects of osteopontin, making it easier for stones to form.

Now, let’s flip the script and look at the female side.

Estrogen does the opposite of testosterone when it comes to oxalate. Higher estrogen levels decrease urinary oxalate excretion, which means a lower risk for kidney stones.
This is why pre-menopausal women form fewer stones compared to men. However, after menopause, the risk rises sharply.

Other conditions like polycystic ovarian syndrome (PCOS) can also increase the risk of kidney stones. PCOS involves a hormonal imbalance that mirrors the oxalate issues we see with testosterone dominance in men.

Outside of hormones, there are other important factors that explain why men form more kidney stones.

First, men tend to excrete more calcium in their urine. This is directly tied to antidiuretic hormone (ADH) levels.
Higher ADH means more urine concentration, and when urine is more concentrated, calcium has a better chance to bind with oxalate or phosphate and form stones.

Men also naturally have higher levels of creatinine, a waste product from muscle metabolism.
Creatinine influences calcium and magnesium levels in the urine.
While calcium is a stone former, magnesium helps prevent stone formation.
Unfortunately, higher creatinine can disrupt that protective magnesium balance.

And then there’s hydration.
Men generally drink less water than women. This isn’t just stubbornness—there’s a biological reason.
Men have a higher threshold for vasopressin (ADH), which means we don't feel thirsty as quickly as women do.

Less thirst means less water intake, more concentrated urine, and—you guessed it—higher kidney stone risk.

That’s why hydration is so critical.
The more water you drink, the less concentrated your urine becomes, flushing out lithogenic (stone-forming) materials more frequently.
And the more often you clear those materials, the less likely they are to crystallize into kidney stones.

In short, it’s not just hormones that make men more susceptible.
It’s a combination of testosterone-driven oxalate production, reduced osteopontin protection, higher calcium and creatinine excretion, and lower natural hydration levels.

But the good news is that hydration and diet adjustments can go a long way toward reducing kidney stone risk naturally—without invasive procedures or surgeries.

If you're a man looking to avoid kidney stones and manage your risk better, start by drinking more water and reconsidering your dietary choices.
It’s not complicated—but it is life-changing.