By Dr Joe

Are there BCAA health risks? What are the BCAA negatives? Is the use of BCAA safe? What are the dangers of using BCAAs?
These are some of the questions I get asked every now and again. So, I thought I might as well tackle them here on this page.

And I need to mention here that talking about possible health risks or side effects of BCAAs is ‘serious business’. Hence much of what you will read on this page is based heavily on science, not conjecture or pure opinions. The resources are also provided.

Of course, there are risks to using BCAAs. Whilst bcaa supplements have become so popular in their use all over the world, sometimes it makes sense to take in a deep breath and examine this new craze objectively.

The sale of bcaa has increased tremendously in the last couple of years. In fact, the bcaa supplement business is now a multi-million-dollar industry.

bcaa health risks


Why is this?

It’s because the benefits of BCAAs are being exploited by sports enthusiasts, body builders and those engaged in intermittent fasting. BCAAs are also used in the medical world, albeit limited use.

Body building requires a good amount of protein consumption to provide essential and non-essential amino acids necessary for new muscle development and maintenance of existing muscle fibres. BCAA provides that, although some researchers like Garlick PJ may have a different opinion regarding that.

The use of bcaas along with intermittent fasting is a well-honed marriage that works for fitness and fat loss. See article on intermittent fasting and bcaa use here.

All of that is all good but we need to look at whether the use of bcaas poses any health risks to the user. I have written about the pros and cons of bcaas extensively here.

Something to remember, is that using bcaas may in practice mean we are increasing our daily protein consumption beyond the recommended daily average, especially if we are eating normally.

The first thing to say, however, is that short-term use of bcaas does not pose any significant health risk to the user. The side effects of bcaa are not stuff the user should worry about when using these supplements, for just a couple of weeks.

So, let’s dive in and prove or dis-prove some of the feared side effects or health risks of bcaas.

BCAA Health Risks

I will tackle the most commonly asked concerns regarding the dangers of BCAA.

BCAA Affecting Kidneys & Kidney Stones

There has been a lot of talk about bcaas negatively affecting the kidneys or bcaa causing kidney stones. Some people are concerned about bcaas causing kidney pain with or without kidney stones.

In a way, this is a genuine concern because when you consume excess proteins either through your regular diet or through the use of bcaa supplements, there is a theoretical risk that the kidneys are being “pushed harder” than they ought to.

On this account of being pushed harder by excessive protein intake from bcaa or regular diet, the kidneys may then begin to malfunction, at least in theory anyway.

The scientific evidence regarding high protein diets or bcaas causing kidney problems is conflicting and no consistency of results have been demonstrated to reach any foregone conclusions.

This experimental study in rats seems to suggest that a high protein diet does cause the kidneys to get bigger (kidney hypertrophy) and to filter more and more.

And if we go by the Brenner Hypothesis, then things get really interesting.

Brenner hypothesis suggests that conditions that cause the kidneys to filter harder and induce higher pressures within the kidneys will eventually lead to kidney injury over time.

Some scientists seem to think otherwise though. This alternative school of thought believes that excessive filtration that happens in the kidneys on a high protein diet is actually an adaptation of the kidneys to the new demand on it, rather than a kidney malfunction.

This Nurses’ Health Study that enrolled 1624 women aged between 42 and 68 years of age and assessed their kidney functions over a 4-year period supports this alternative viewpoint.

The conclusion from that study was that a high protein diet like using bcaa would not initiate a decline in kidney function in normal healthy individuals. However, if you had pre-existing abnormal kidney function, a high protein diet such as using bcaa would accelerate the progression of decline in kidney function. So, BCAAs are best avoided, if you have a pre-existing kidney malfunction.

What About BCAA and Kidney Stones
What we do know is that the food we eat plays a huge role in the formation of kidney stones.

But do bcaas cause kidney stones and in turn kidney pain? This is a bit hit or miss. There are studies like this one that shows a direct correlation between high protein diet (especially animal protein) and calcium oxalate kidney stones formation.

With a high protein intake, it would appear in theory at least that stone formation in the kidneys would increase because of increased excretion stone forming agents like uric acid and calcium.

That’s the theory and indeed you could argue that BCAAs have a theoretical risk of enabling kidney stone formation.

But when you examine the literature, there is no conclusive evidence that if you embark on a high protein diet for instance by using bcaas, you are likely to form kidney stones. Indeed, this study of 96,245 women aged 27 years to 44 showed a risk reduction between high protein diet and kidney stones.

As it happens that same study also showed that adequate fluid consumption reduces the risk of kidney stones.

So, here is the advice. If you are going to use bcaa supplements, it would be prudent to drink plenty of water to prevent kidney pain in the short term and kidney stones in the long run.

I cannot emphasize the importance of adequate hydration when using bcaas as far as kidney pain or kidney stones are concerned.

bcaa and kidney stones

Don’t forget that when you exercise you lose a lot of body fluid through sweat and it is very easy to become underhydrated. Dehydration in itself regardless of whether you are using bcaa supplements or not is the bedrock of most kidney stones.

So, drink plenty of water and you should be fine. Also watch out for other supplements that you may be using along with the bcaas that may cause you to pass urine a lot more like caffeinated BCAA supplements.

These are supplements that creatively combine bcaas and caffeine together as one. Personally, you will be pushing the boundaries by using those combination supplements. If you do, my advice will be to drink even more.

BCAA and Insulin Resistance (Type 2 Diabetes)

There has been some grumbling in some quarters that the prolonged use of BCAAs and indeed prolonged consumption of a high protein diet may be associated with the development of insulin resistance and subsequently Type 2 diabetes.

I have been looking at the scientific evidence between bcaas and diabetes. Again, the evidence is conflicting.

This is not surprising because we have evidence that bcaas do signal insulin to spring into action.

Of course, we know that insulin’s main job is to lower blood sugar quite apart from affecting the metabolism of available amino acids.

So, how for heaven’s sake, does a diet high in branched-chain amino acids or prolonged use of bcaas result in insulin resistance and high blood sugar (type 2 diabetes)?

I suppose it’s all in the genotype and environmental interplay. Wolever and his colleagues studied the North American Aboriginal population and confirmed this interplay. They found a 38% increase in the risk of diabetes when the diet was a high protein one in that Aboriginal population.

Having a diet that is deficient or low in fiber, but high in protein can result in insulin resistance and type 2 diabetes. Dietary fiber-depleted foods high in either starch or protein predispose the individual to diabetes.

Now, does that mean bcaa use will result in insulin resistance and type 2 diabetes. Probably not. Especially if you don’t use bcaas for a long period.

Short-term use of bcaa supplements for 4 months and under shouldn’t really be an issue as far as insulin resistance and diabetes are concerned.

But if you are going to use bcaas for a long time, you need to bear in mind the health risk of diabetes or insulin resistance because amino acids inclusive of the ones in bcaa can have a bi-directional effect on insulin, it would appear.

What does bi-directional effect mean?

It means bcaa can positively call on insulin to store proteins whilst at the same time have a negative effect on some of the functions of insulin. Functions such as control of blood sugar.

Just be careful. As a precautionary measure though, if you are going to use the bcaa supplement for a long time, please make sure you add a lot of fibre to your diet. Fiber seems to have a calming effect on the mechanics of blood glucose control and possibly it’s metabolism.

BCAA and Joint Pain

Are bcaas good for joints or are they bad for your joints?
Some individuals have wondered whether joint pain is one of the dangers of taking bcaa supplements. Indeed, when you develop joint pain or arthritis at the time of commencing a supplement, your mind automatically thinks; could the supplement be the cause of this joint pain?

That is fairly natural and rational thinking.

However, in nearly all cases, this is a mere coincidence rather than the source of the problem. Just make sure you don’t have issues with gout though.

Something to realise is:

Branched-chain amino acids actually aid in musculoskeletal injury.

BCAAs may be useful in arthritis. In actual fact, when you do have injury affecting the muscles or joints, you need a good dose of bcaas to facilitate the healing process.

I have talked about how bcaas actually help with the synthesis of proteins already and there is scientific proof to that effect. The protein synthetic function and inhibition of protein breakdown forms the basis on which bcaas should help with arthritis.

BCAAs may also calm the inflammation associated with arthritis especially when used in conjunction with methionine as I will explain shortly.


Your body needs these essential amino acids in bcaa supplements along with another essential amino acid called methionine to help build new connective tissue. Any system that helps connective tissue recovery like cartilage formation is always a beneficial thing for your joints.

A lot of joint pains are the result of problems with connective tissue whether it be related to sports injury or ageing. Arthritis for the most part has its origins from connective tissue malfunction.

Therefore, one needs a diet rich in these essential amino acids to help with the formation of collagen. Collagen is the bedrock of connective tissue. Without collagen, there is no connective tissue. And without connective tissue, joint pain will rule the day.

Methionine, for instance, is one essential amino acid that is needed for cartilage production because it supplies sulphur to the body. I know methionine is not a branched-chain amino acid, but I am stressing the point that along with the bcaas, methionine does actually relieve joint pain and promote healing by stimulating connective tissue formation.

bcaa side effects


What am I saying here?
I am saying that bcaas rather than cause joint pain, they indeed do the opposite. BCAAs are actually good for joints.

Bcaas promote joint healing rather than cause joint pain. And if BCAAs are taken with methionine they provide anti-inflammatory function which helps to provide relief from joint pain.

BCAA and Hair Loss & Hair Growth

Do BCAAs cause hair loss or do BCAAs stimulate hair growth? That is the question. I have been researching the relationship between bcaas and hair loss or hair growth.

For one thing I do not have a personal experience with bcaas causing hair loss or bcaas causing hair growth, nor do I know anyone close to me that has had any such experience with BCAAs.

So, what I have written here about how bcaa relates to receding hairline or hair growth is based on research. In the course of establishing the facts regarding hair thinning, alopecia and bcaa, I came across claims by two experts who stated that the use of protein shakes containing bcaa actually leads to hair loss.

Their theory in support of this claim is that bcaa use causes a spike in testosterone levels which in turn raises dihydrotestosterone (DHT) levels in the body.

Now dihydrotestosterone, DHT, is a weird hormone. Dihydrotestosterone is the active metabolite of testosterone, but it is weird hormone.

What do I mean by that?

Well, dihydrotestosterone is the hormone that stimulates facial and body hair growth amongst other functions. In fact, dihydrotestosterone, DHT, is the nemesis of women with polycystic ovaries. It’s the hormone that makes those women with polycystic ovaries hirsute.

Now whilst dihydrotestosterone (DHT) stimulates facial and body hair growth, it does the exact opposite on the scalp. Dihyrotestosterone (DHT) causes hair loss or hair thinning on the scalp. And the scalp is where you really want your hair to bloom. Now you see why I say DHT is a weird hormone.

Anyway, back to the claim by these two experts. These two experts on the basis of the above weird behaviour of dihydrotestosterone opine that protein shakes and in particular bcaa use does lead to hair loss or alopecia.

I had a good search on pubmed library looking for scientific evidence to back that claim. I saw none.

My view is that, based on dihydrotestosterone effect, it is quite possible that BCAAs may cause hair loss but this has not been scientifically studied yet, as at the time of writing. It is a theoretical association supported by hair expert’s opinion. I haven’t named the two experts here because I may unwittingly be promoting them.

Part of the reason why I haven’t named them is because the two experts have their own registered hair growth products on sale. So, maybe, just maybe, conflict of interest could be at play here. Just a thought!

Are BCAAs good for hair growth?

Now to add to the confusion:

I also gathered from my research that bcaa can actually facilitate hair growth in the same breadth. But not in the regular supplement form as you know it, I should add.

How’s this possible?

Hair growth is naturally engineered by the presence or absence of potassium channels within the hair follicle. Even if the potassium channels are present but aren’t functioning properly, hair growth will be negatively affected.

The absence or poor functionality of the potassium channels reduces the membrane potential of the hair follicle; hence growth is impaired.

What’s this got to do with branched-chain amino acids, I hear you ask.

Well, if you can raise the membrane potential of hair follicles by stimulating new potassium channels, hair will grow. Any mechanism that positively induces new potassium channels within the hair follicle will promote hair growth.

Guess something that has that capability – BCAAs.

bcaa hair loss

BCAAs stimulate development of new potassium channels in hair follicles and as result stimulate the growth of hair growth. That is why new formulations of hair growth products now incorporate branched-chain amino acids in them and they claim to have lasting results.

I haven’t personally tried these new hair growth products containing BCAAs myself, so I cannot vouch for them. I suppose they are worth a good try if you have issues with receding hairline or hair thinning.

BCAA and Libido

Does the use of bcaa cause low libido or heighten libido? Big, big question.
When it comes to libido in humans, things get really murky. Never have I had a difficult and challenging consultation in the clinic than when a patient complains of low libido.

One reason is the patient quite naturally is expecting me prescribe a wonder drug that will fix the problem. How I wish it were that simple.

Yes, there may be organic issues causing the low libido problem but I gotta tell you, the psychosocial contributors to low or lack of libido cannot be over-emphasized.

Here is something you should know.
Libido is hugely affected by:

  • How sensitive the frontal lobe of your brain is to sexual cues.
  • How strong or weak your psychological inhibition is.

I don’t want to go into huge detail about this because that is a whole topic in itself. Could be a book actually, thinking about it.

So, to accuse a substance like bcaa of causing low libido may be an unjust thing to do because libido issues are too complex. Doing so will be over-simplifying the issue.

BCAAs may or may not cause low libido. The flipside of that is BCAAs may or may not increase libido. The point being…everyone is different.

I could take BCAAs and my libido will be hitting the roof. In the same vein, you could take BCAAs, and your libido may crash. Can you blame the bcaas for your libido? That would be a tricky thing to do.

What we do know is:

BCAAs do reduce the level of serotonin (5-HT) in the brain. Serotonin is involved in both your mood and libido by extension. Once serotonin receptors in the frontal lobe of your brain are activated, psychological inhibition is diminished, but the effect on sexual cues is inhibitory.

So, BCAAs lowering 5-HT in the brain is actually a good thing for libido, rather than having a negative impact on libido.

And there is another explanation:

BCAAs actually cause a spike in testosterone levels as shown in this study and this other one. And would you believe it, BCAAs also cause a rise in Human Growth Hormone (HGH) levels in the body.

Ah, now it gets interesting.

Testosterone and Human Growth Hormone increase sex drive like crazy especially when your body gets a good hit from them. Best effect is at initial exposure.

If BCAAs can drive up both testosterone and growth hormone, then BCAAs should in theory actually revv up sex drive, rather cause it to crash and burn.

The conclusion from all of these hormonal interplay is that it is difficult to point the finger at BCAA if your sex drive takes a hit. If you however still have doubts, then stop using the bcaa supplement and see if your libido picks up again.

If you notice a difference, then you have made your own diagnosis regardless of whatever someone else tells you.

Suggested further reading:
How To Supercharge Your Life and Restore Glowing Good Health