T Nation

BCAA Reaction


Question for any nutrition experts...I've noticed that when ever I have BCAA's in my PWO shake I start getting mild anxiety or panic attacks, trouble sleeping, throbbing pressure behind my eyes & frequent urination. When I stop using it, those symptoms disappear.

Is it possible that some people may not tolerate BCAA's or have some sort of allergic reaction. Or, do you think maybe my BCAA's have gone bad (I got it through bulknutrition, & there is no expiration listed). Has anyone else had a similar experience?

Also, how essential is BCAA supplementation if my diet is in order & I have a solid PWO shake? Will I really be missing out on that much muscle growth without it?

Thanks for any help.


Since BCAAs are essential amino acids, you get them any time you consume complete proteins. You'd have to have a pretty rare disease to be allergic to an essential amino acid.

It's not critical to supplement with additional BCAAs if protein intake is adequate, but I believe they can still make a significant difference. I'm currently taking 10-20 Biotest BCAA tablets daily, depending on my training schedule, and am recovering faster from intense training. I also appear to be leaning out as well despite keeping my dietary intake fairly consistent.

My guess is that the product you're using is contaminated with something that's causing your symptoms.


Yeah, it's odd. BCAA's can be a problem in some rare cases like people who have Maple Syrup Urine disease but you'd know if you had that!

The headaches etc sound a little like a reaction to glutamic acid, are you able to tolerate MSG? Possibly if not the product is contaminated with this (though unlikely) or something else. It's very strange.

While these amino acids are present in the diet their effect start to change when you change their absorption kinetics (i.e. start taking them as fee amino acids not whole proteins) so that may have something to do with it ? it certainly does with glutamate.

As I keep saying though it is very odd, not something I have come across in all my years practicing.

Drew Price


Thanks for the feedback...I do have to agree, it does seem odd! On a similar note, I have noticed that over the past year I've become progressively more sensitive to certain food (possible allergic reactions). I've almost completely cut out all gluten & dairy from my diet because of a variety of adverse reactions. Since gluten is a protein (I believe) & amino acids are derived from protein, is it possible I'm not able to tolerate certain protein sources?

Also, to answer your question, I am very allergic to msg...my face gets flushed, I get incredibly tired & dizzy with peircing headaches. Would you recommend I see a specialist about these allergic reactions? Or, are they just going to tell me to do what I'm already doing..."avoid anything that makes you feel like shit"



This is interesting, especially since I'm pretty new to BCAA and I did notice some anxiety that was not there before.

Before that, right when I started BCAA, I noticed enhanced visual perceptions (almost like Spike), a bit of euphoria and a very slight confusion, like when you're so relaxed you don't care what happens - but it was all psychological, not physical.
But this has morphed more recently into a slight negative mood change.
I will discontinue BCAA at some point to see if whatever happened was due to it.

Note: I'm pretty sensitive to any kind of drugs. When I take anything, my body will dutifully reproduce all the symptoms in the book, down to the last one.


Gluten intolerance is down to the behavior of the protein not the amino acids that make it up so that wouldn't necessarily be connected.

With glutamate the problem is not so much the amino acid (although it is a 'excitotoxin' in certain concentrations which is the problem) it is the rate at which it is absorbed.

When you put MSG on a food it means you are going to absorb a lot of the free AA very quickly causing an acute rise in the blood concentration giving the symptoms. There's also glutamate in the proteins in the same meal but these are absorbed differently.

You are correct, you doc is just going to tell you to avoid it. As I said the 'behavior', the physiological impact amino acids change when you ingest larger amounts of the free form but I would be VERY surprised if there was anything to do with BCAA that was deleterious if you are healthy, following dosing guidelines and using a quality product.

I'll do a literature search today if I have time as you piqued my interest I'll see if I can find something other than that which involves very rare metabolic diseases. You won't get an answer for a bit though as I am in London (UK).

Perhaps if there are any of the contributers reading this they can pitch in?

Drew Price


Personally I think all of you are getting a nice placebo effect, and going with it.
The only time i EVER feel ANYTHING from bcaas is when I take them DURING a work out. And it's not anxiety, and all this other stuff.


Yeah, that was a real intelligent response. The guy potentially has allergic reactions or possibly a bad product and you come up with that. Boy I wish we could trade brains!


Well than I guess he's a fricking vegeterian, and anti dairy because the same mother f-in AMINO ACIDS are found in those foods. Grow up.


Good Lord. Yes, they would be found in any whole proteins out there... but not in isolation. That's the whole point. Taking it completely independently of those other components does make a difference. Stop acting like a tool.


so please explain to me how that makes a friggin difference? please.


I recently started taking BCAAs (along with grape seed extract and blueberry extract) and I had a really strange reaction. It felt as though my blood pressure rose considerably and I also felt some anxiety.
I lowered the dosages the next day and haven't felt anything like that first time, just a little extra energy.

Any ideas on this reaction, oh T-Nation brain trust?


Well, I'm getting more "data points".
BCAA seems to "amplify" whatever emotional state I'm in.

If I'm in a positive mood, energetic, etc., the only effect is an enhanced visual perception and mild euphoria, almost like Spike.

If I'm stressed out by shit from work and stuff like that, a mild anxiety may pop up after taking BCAA.

Aminoacids are to protein what glucose is to cellulose.

Glucose = sweet nourishing stuff
Cellulose = tree bark, paper, cardboard. Not sweet, not nourishing (unless you're a worm)

Yet they're "the same stuff". Same molecules. Except in cellulose the small molecules are chained up together to form a bigger molecule, while in glucose the small molecules are separate, free.

Same deal with aminoacids and protein.

Get it now?

There are also many reports of psychological effects of BCAA in the original BCAA thread:


So no, it's not placebo.


The fact is there is a chance that it may well be placebo, coincidence etc but it's worth trying to rule things out before you come to that opinion!!!!


One of the confounding factors is that people often start mixing new foods, habits and behaviors all at the same time.

You know, if someone starts exercising after being sedentary for ages, there will be a plethora of effects and changes. To go and throw a ton of different supplements into the mix makes it really hard to know what is or isn't doing what.

Anyhow, I'm not trying to say that this is the case here, but just to be careful of making an unjustified leap. We, people in general, seem hardwired to attribute things to food or changes in food, perhaps as an instinctive survival attribute, but this instinct can be tricked by other factors.


Just found this on the net...curious if this may correlate with my BCAA reactions: "inherited deficiencies of enzymes involved in leucine metabolism result in a group of disorders referred to as leucine metabolism disorders.

In these cases, the body is not able to break down one of several metabolites of the essential amino acid leucine, resulting in toxic levels of that metabolite in the body. Approximately 60 cases of leucine metabolism disorders have been reported. This disease generally result in metabolic acidosis, which can lead to neurological damage, coma, and death if not corrected"


Is it really that hard to get? Whole proteins are made up of the full spectrums of amino acids and they vary in the amounts of each of those AA's. For instance, turkey tends to be higher in tryptophan which likely contributes to why you feel sleepy after eating a bunch of it (either that or the gobs of food consumed with the turkey on your average Thanksgiving).

If you then start taking individual amino acids in isolation, your body is going to absorb them and treat them differently than it being found as a whole protein. Think of how Dave Barr bangs on glutamine all the time for the insulin spike response it (according to DB) promotes. That isn't happening from eating red meat which also contains that same amino acid, right?

We on the same page now?


mbjoyce, You were right all along! Your gluten allergy or sensitivity is tied to the BCAA, because it contains SOY and we all now know that soy contains gluten! Always trust your gut instinct (and reaction)!


BCAAs lower plasma tryptophan and tyrosine levels which explains your symptoms. It might exacerbate anxiety and depression in susceptible individuals due to lower serotonin and dopamine. That’s why I no longer take protein powders or EEAs. On the fence with Plazma too since I get similar sides