Kidney problems in bodybuilders

By Kim Crawford, M.D. Last updated: February 13, 2021
kidney glomeruli

Why do bodybuilders have kidney issues?

kidney glomeruliThe waste products of protein can “stress” the working capability of the kidneys. The specific part of the kidney which is involved is the filtering units of the kidney called the glomeruli.

The effect is called “hyper-filtration.” Stay with me- I’m not saying it’s just the protein and in fact I’m not saying it’s the protein at all at this point.

The theory of how chronic high-protein intake harms the kidneys suggests that the excessive hyper-filtration is the problem.

The pressure needed to get rid of protein waste products might eventually lead to the formation of scar tissue in the glomeruli.


When that happens, chronic kidney disease can result. Or so the THEORY goes. The very fundamental problem with this theory is this: thus far it has been shown to occur only in selected animal studies and in people who already had pre-existing kidney disease.

Recent animal-based studies, however, have suggested that  protein might be a problem,though. The intake of 35 percent of total calories or what works out to about 1.5 grams/ pound of body weight may indeed stress the kidneys.

The 35 percent figure is often suggested by experts as the upper level limit for safe protein intake. It tends to be the minimal amount eaten by most competitive bodybuilders. Where this number comes from, I just don’t know as clinical studies show you just plain “can’t use” more than 1 gram per pound of bodyweight to make more muscle. If that.

Eating a high-protein diet increases the kidneys’ workload-O.K.-that part is recognized as fact. But the question remains (much to the surprise of bodybuilders I discuss this with)  whether that will cause long-term damage to bodybuilders who have normal kidneys to start with.

No one argues the fact that eating less protein  reduces the work-load on those with existing kidney problems. No one argues that reducing protein intake in everyone with kidney disease will slow the progression to kidney failure. However, early stage kidney disease is silent. You’re only made aware of kidney damage with constant lab testing.

O.K.-what about the hyper- filtration in the kidneys that is caused by eating a high-protein diet? That does happen. Well, It just might be a normal adaptation. One theory is that eating more protein causes more glucagon release from the pancreas. This hormone works with cyclic AMP, to decrease the pressure of  filtration through the glomeruli.


needs serious skin care on that baby bellyThis theory comes from looking at the physiology of pregnancy. During pregnancy, the glomerular filtration rate increases by as much as 65 percent in healthy women.

But then, about three months after childbirth, it returns to completely normal. The increased filtration is needed to deal with increase in waste products made by mom and child.

It causes NO harm to normally functioning kidneys. Hyper-filtration also is seen when one kidney is removed. The remaining kidney increases its filtration rate to make up for the loss of the other kidney.

Again, no harm occurs to the one remaining double-duty kidney.

Startlingly enough, most of the bad rap given to high-protein diets regarding kidneys comes from one particular medical journal article.In a (get this! )1982 review in the  New England Journal of Medicine, the author suggested that anything that increases glomerular filtration can cause sufficient injury to cause chronic kidney disease.

However, the author based his assumptions entirely on studies with animals and with humans who had preexisting kidney disease.

 Current conclusion regarding protein:

A normal intake of water by drinking it until urine is clear should theoretically be enough to protect the kidneys from an excessive protein load. In fact, a study of bodybuilders published a few years ago found no kidney impairment in 35+ well-hydrated  bodybuilders who ate  up to 1.9 grams of protein per kilogram of bodyweight each day.

So now that we have the high protein myth out of the way, what ARE the issues?

Bodybuilders often will take water pills-diuretics to “look more shredded.” If you couple high protein filtration demands with dehydration then THAT is going to stress your kidneys.

Obviously one of if not the most kidney preserving activity you can do is to make sure you get adequate fluids. This is particularly true for bodybuilders on high-protein diets.

The excretion of urea (in the form of BUN of blood-urea-nitrogen) requires a good amount of water to help the kidneys process and excrete it in the urine.

Bodybuilders who dehydrate themselves either by severely restricting fluids before a contest or using potent diuretics are endangering the ability of their kidneys to excrete BUN. And there’s more, of course.

Human  growth  hormone, painkillers, creatine supplements, and diuretics:

All of these are used to create the “ripped” look that bodybuilders want.

And what’s counter-intuitive is that the high concentration of muscle mass puts stress on the body, including the kidneys, as if the athlete were obese.

Determining the extent of the damage bodybuilders inflict on themselves is difficult.

One reason is  because there is little interest in financing studies the other is that bodybuilders are not always honest about what they take when they talk to doctors.The whole “bodybuilder cocktail” is thought to be responsible for kidney issues.

HGH is NOT a big problem where I’m concerned. And there may be one group of products which are the worst. Note that creatine “by itself” does NOT harm kidneys as was once thought. As a FYI I’d prefer you took more HGH and less anabolics-HGH can be pushed up pretty far and when you get to the end I’ll tell you more.


Competitive bodybuilders routinely take IM plus oral anabolic steroids to achieve their enormous physiques. This is the ONE instance where a high-protein diet may negatively affect kidney function.

One study involving bodybuilders with scarring and reduced function of renal glomeruli had anabolic steroids AND high protein and in the mix-both thought to worsen the effect of the other.

That study began 10 years ago when a smart Columbia University physician noticed that a bodybuilder had an advanced form of kidney disease. She started looking for similar cases and eventually found and studied 10 bodybuilders (all men) with serious  kidney disease who acknowledged that they had used anabolic steroids.

All 10 men in the  case series showed damage to the glomeruli or the filters of the kidney.

Nine had an irreversible disease known as  focal segmental glomerulosclerosis.

Their disease was worse than in obese patients with a higher body-mass index.

The conclusion was that a combination of a very high-protein diet—(more than 300 grams a day)—and fairly large doses of anabolics steroids would lead to kidney damage.

So how to stay safe?

I’m going to advise you first to avoid diuretics and stay hydrated. Next I’m going to advise you to use higher doses of  safe supplements such as branched chain amino acids (bcaa  powders) and l-glutamine. The BCAA’s also help with DOMS, giving you muscle soreness relief as well.

Even make sure you’re using the cleanest whey protein. Think about what else “safe” you can add to your nutritional stack-nitric oxide enhancers are great. Acetyl-l-carnitine supplements are useful too.

If you are taking diuretics I want you to reduce protein and stop creatine. I’m going to ask you NOT to take anabolics, as they can cause liver disease, heart disease, blood clots, and more.

I’m going to ask you to look into IGF1LR3 and we know you can push your IGF1 to 350 and maybe as high as 500 safely. Over 350 I ask you to get q3-4 month echocardiograms.

Here’s how to watch your kidney function.

Make sure you hydrate until your urine is clear at least. Monitor blood tests for creatinine, BUN and eGFR (glomerular filtration rate). Your creatinine will be up due to your muscle mass but when we see it inching towards 1.8 mg/dL we get a bit worried. BUN can be up due to dehydration.

The most reliable test is the eGFR and should be monitored regularly if you are at risk.The labslip will show you what a normal eGFR is for your age and if you see this number “going south” I would advise you that a perfect lean body mass physique isn’t worth getting a kidney transplant (or dying) over.SO how do you get as big and lean as possible and stay safe doing it? You join other elite bodybuilders and let me “watch over you” so you do NOT “crap out” your heart, kidneys, liver, etc. I “watch over” my national guys like a doctor-hawk and they are all in excellent health.

Something no one has studied by my elite guys are experimenting with due to my hunches: mitochondrial augmentation. It just might give you the “edge”- we just don’t know. But since most of our mitochondria reside in our brain, heart and muscle tissues, it makes sense to me. What about you? This is the mitochondrial supplement my guys like most.

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