5 Allergic Reactions to Pre-Workout Supplements


Studies show the best pre-workout supplements are safe to use. However, many users report a long list of common side effects – often the result of allergic reactions.

And considering a lot of pre-workout supps mix a wide range of different ingredients (some of which are low quality and artificial), this doesn’t really come as an almighty shocker.

So if you’re suffering from any of the symptoms on this list when taking your pre-workout supp of choice, it’s probably time to change it for something better.

Read on to find out what could be causing your pre-workout allergic reaction – and for tips on what to use instead…

1. Itching

Studies show Beta-Alanine may induce a slight reduction in muscle fatigue. It could also help you lose a small amount of fat and gain a small amount of muscle.

For this reason, it comes as no surprise to find it in many different pre-workout supps on the market.

You may already know itching and tingling are common side effects of pre-workout supps. But you may not be aware Beta-Alanine is the usual culprit for these unpleasant feelings.

This modified amino acid can cause you to itch or tingle anywhere on your body. Most sufferers report the sensation in their neck, face, or back of their hands.

Is your pre-workout causing a prickly feeling across your body, or giving you pins and needles? Then we recommend looking for a new pre-workout supp without Beta-Alanine.

How to stop itching from pre-workout supplements

Creatine does everything Beta-Alanine can.

But it also boosts your testosterone for greater muscle gains and better overall performance. So if you want to stop the itching caused by your pre-workout, swap your supp with Beta-Alanine for one with Creatine.

2. Hives and Rashes

pre workout rash

Many lifters also report breaking out in hives, red skin and rashes as a result of taking a pre-workout supp. The blame for this usually firmly rests at the door of Niacin (aka vitamin B3).

As a B vitamin, it helps convert carbs into energy (your body’s fuel). It’s also proven to reduce cholesterol and help prevent hardening of the arteries.

This in turn sends vital nutrients to your muscles to aid their growth – which is why many manufacturers load their pre-workouts with Niacin.

Niacin Flush

However, “Niacin Flush” [1] is very common.

And the problem with a lot of pre-workout supps is they’re usually packed with way beyond the FDA’s recommended daily amount (RDA), which in the case of Niacin is 20mg [2].

Too much Niacin sends it ability to dilate your blood vessels into overdrive – which is what causes the flushing sensation.

How to avoid pre-workout rash or hives

To avoid Niacin Flush and the associated burning or itching, avoid taking the vitamin in a supp.

Instead, get your proper daily dose by eating poultry, lean beef, nuts, beans, or whole grains.

And as far as your workout regime goes, look for a pre-workout that doesn’t contain Niacin – and use it only as part of a healthy, calorie-restricted diet.

3. Jitters

pre workout jitters

Stimulants are a necessary part of any decent pre-workout supp. They are what give you the energy, focus and endurance to smash through those hard-to-hit targets.

It should go without saying that the likes of ephedrine are dangerous stimulants – and they’re banned by the FDA for a reason.

But too much of anything is bad.

And this includes great natural (and safe) stimulants like caffeine. The right amount of caffeine can be the driving force of a solid pre-workout supp.

The issue is that many brands load their pre-workouts with enormous amounts that are bound to cause you to crash – hard.

To get the best out of caffeine for these purposes, avoid taking any pre-workout supp containing over 200mg of the stimulant.

We also advise taking no more than the RDA (400mg) for caffeine each day. Also look for a supp that doesn’t contain any other stimulant – caffeine is the only one you need.

4. Body Odor

fish body odor

Some common pre-workout ingredients also cause unpleasant body odor.

You no doubt want to be aware of this – after all, what’s the point of getting shredded if no-one wants to go near you because you stink?

Studies show that Betaine and Choline cause fishy body odor [3].

Betaine (or TMG) is a molecule that helps balance water levels in your body’s cells and ramps up your metabolism. Choline is an essential nutrient that can improve focus and muscle growth.

Want to smell like rotten fish? Didn’t think so…

However, supplements usually contain high amounts of these nutrients – and ingesting too much of either may cause you to smell like rotten fish. Take no more than 500-1000mg of Betaine and 500mg of Choline (adequate intakes).

Like many of the ingredients on this list, avoid using supps which use Choline and Betaine in their extracted forms.

Betaine is a key nutrient in Beta Vulgaris or Red Beet. Beet Root won’t cause fishy odors in supp form as it contains just the right amount of Betaine.

Meanwhile, meat, poultry and peanuts are all good sources of Choline.

5. Headaches

Many pre-workouts are packed with artificial sweeteners. These usually come in the form of:

  • Aspartame – 200 x sweeter than sugar
  • Acesulfame – 200 x sweeter than sugar
  • Sucralose – 650 x sweeter than sugar
  • Saccharin – 300-400 x sweeter than sugar

As sugar’s reputation continues to plummet, artificial sweeteners have become more common as the ‘healthier’ option – in fact, they’re everywhere.

From those little sachets you find in coffee shops, to cans of soda, diet foods and even pre-workout supps – artificial sweeteners lurk around every corner.

But while they may be better for your teeth, sweeteners are not as healthy as they might seem.

In fact, they pose a long list of nasty side effects, including everything from sickness, to birth defects and pre-workout headaches. In fact, headaches top the list of allergic reactions to artificial sweeteners.

As a result, we advise avoiding any supp with artificial sweeteners. Instead, choose a pre-workout supp with the following key ingredients…

Safest Pre-Workout Ingredients

‘Smart Caffeine’ combo

As we mentioned earlier in this article, Caffeine is a great natural stimulant – but can make you feel jittery.

That’s where Smart Caffeine [4] comes in…

This mixes the stimulant with L-Theanine, a relaxant agent which smooths the delivery of Caffeine. This gives you all the focus and energy with none of the crash.

Creatine Monohydrate

Creatine is an essential nutrient. You need it to store fat and carbs to use as energy – and without it your body would simply stop working.

As result, the molecule is very common in fitness supps. In fact, we wouldn’t trust any pre-workout without it. However, you should be aware that Creatine comes in two main forms: Creatine HCL and Creatine Monohydrate.

The HCL (or hydro-chloride) version dissolves better in water and is easier to mix. However, we prefer tried-and-tested Monohydrate.

Why? Because it’s been around much longer and we know it works – and if it ain’t broke, why try to fix it?

Citrulline Malate

Plain old Citrulline is well-known for boosting endurance and reducing fatigue, which makes it great for muscle pumps.

And while adding Malic Acid to the mix might not seem a vital detail, it’s proven to remove ammonia from your system and stop fatigue dead in its tracks.

As a result, Citrulline Malate gives you a crucial boost in endurance and overall performance.


If you suffer from any pre-workout allergic reaction, it should be easy to avoid.

We don’t really understand why any pre-workout supp includes Beta-Alanine in its formula. While research does show it can boost endurance and provides modest muscle gains, Beta-Alanine isn’t as effective as Creatine for this purpose.

While the likes of Betaine, Choline and Niacin are essential nutrients, you can avoid smelling like rotten fish or breaking out in pre-workout hives by simply sticking to a healthy diet.

The overarching rule here is never take any pre-workout supp that contains too much of anything and look for one with all-natural ingredients.

4 Gauge by Roar Ambition

4 Gauge has to be the best pre-workout supplement we’ve tried – and we’ve tested a lot!

With 100% natural ingredients, 4 Gauge not only gives you the energy and endurance you need to push through barriers – it’s also safe.

This product uses none of the problem ingredients listed above. Choose this supp and say goodbye to itching, blotching, burning sensations and fishy odors.

In addition, the use of Creatine Monohydrate, Smart Caffeine and Citrulline Malate makes 4 Gauge a potent mix of everything you need to prepare for the best workout of your life.


[1] Kamanna, V.S. The mechanism and mitigation of niacin-induced flushing

[2] FDA Vitamins and Minerals Chart (available online at https://www.accessdata.fda.gov/scripts/InteractiveNutritionFactsLabel/factsheets/Vitamin_and_Mineral_Chart.pdf)

[3] Messenger, J. A Review of Trimethylaminuria: (Fish Odor Syndrome)

[4] Owen, G.N. The combined effects of L-theanine and caffeine on cognitive performance and mood

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