Is Collagen Supplementation Safe for Your Kidneys?

What is Collagen?

Collagen is a natural protein that makes up your body’s connective tissues, like skin, bones, muscles, and joints.

Its main function is to give structure and strength to these parts, kind of like glue holding everything together.

Collagen protein supplements contain an amino acid called hydroxyproline, which the body metabolizes into oxalate. That's how a nephrologist describes the way your body processes collagen. — Dr. Majd Isreb, M.D

As we get older, our bodies make less collagen. That’s why many people turn to collagen supplements, which usually come as powders, drinks, or capsules.

These supplements contain hydrolyzed collagen (also called collagen peptides), which is collagen broken down into smaller pieces so your body can absorb it more easily.

People commonly take these supplements to support:

• Skin hydration and elasticity
• Joint and bone health
• Hair and nail strength

While these benefits of collagen are widely promoted, it’s essential to understand how collagen interacts with the kidneys.

Collagen and Kidney Stones: The Hydroxyproline Connection

Collagen and Kidney Stones

One of the main concerns surrounding collagen side effects on the kidney involves hydroxyproline, an amino acid abundant in collagen.

That is, when digested, hydroxyproline can be converted in the liver to oxalate a compound that contributes to the most common type of kidney stones: calcium oxalate stones.

A 2005 study showed that consuming high doses of hydrolyzed collagen significantly increased urinary oxalate excretion. However, this study used very high, concentrated doses, far above what is typically consumed in standard supplementation (10–20 grams per day).

Now, for most people, this conversion does not pose a significant health risk, especially when collagen is taken in moderation.

To learn more about how collagen, and other foods, can be linked to kidney stones, check out this helpful video from Melanie Betz, a registered dietitian, on The Kidney Stone Diet YouTube channel.

She'll explain how these foods affect a substance called oxalate and give you tips to prevent kidney stones.

Protein Intake and Kidney Health: What’s the Risk?

Collagen supplements are notably high in protein; they're made up of about 90–97% protein.

For most people with healthy kidneys, this isn’t a problem. In fact, studies (including ones by the World Health Organization) show that high-protein diets do not damage healthy kidneys.

But if you have chronic kidney disease (CKD), it's a different story. When your kidneys are already weakened, eating too much protein can make them work harder, possibly speeding up damage. That’s why people with CKD are usually told to follow a low-protein diet.

It’s therefore reasonable that for people with healthy kidneys, collagen protein is generally safe, but for those with a well-diagnosed kidney disease, talk to your doctor before taking collagen.

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Who Should Avoid Collagen? (At-Risk Groups)

While collagen is safe for most people, certain groups should exercise caution: the high-risk groups include:

• People with chronic kidney disease (CKD) - Collagen contains amino acids that may increase the burden on already compromised kidneys.
• Those prone to kidney stones mostly calcium oxalate stones - Collagen supplements can contribute to oxalate buildup, increasing the risk of stone formation.
• Individuals with primary hyperoxaluria, a genetic disorder - Since collagen metabolism can lead to oxalate production, it may exacerbate symptoms.
• Anyone with underlying kidney concerns should consult a doctor before taking collagen supplements to ensure safety and proper dosage.

How to Use Collagen Safely

To minimize any potential kidney risks, especially if you’re concerned about oxalate build-up, consider these safety tips:

• Stay Hydrated - Drink plenty of water throughout the day to help flush out oxalates, a byproduct of collagen metabolism.
• Pair with Calcium-Rich Foods - Calcium binds to oxalate in the gut and reduces its absorption. Include foods like yogurt, cheese, or leafy greens when taking collagen.
• Avoid Mega-Dosing - Stick to the recommended 10–20 grams per day, unless your doctor advises otherwise. Excess collagen may increase the risk of oxalate buildup.
• Monitor Kidney Health - If you're at risk (e.g., history of kidney stones or CKD), get regular kidney function tests and consult your healthcare provider.

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