Are Pre Workout Supplements Harmful?


Many people who workout will, even with proper diet in place, find that some days they are just dragging. It might be the kids keep them up at night, it might be a late night with friends or a late movie or it could be stress at work is sapping their energy. Whatever the case some days it is just hard to pull yourself outta bed to do anything. (Once I let gravity pull me out of bed thinking once I was out I’d get up…..I woke up an hour later on my floor and it was even harder to get up. Lame!)

Others may go to workout in the afternoon when they are feeling the early afternoon nap coming on. It’s a similar situation for many people. It’s a “the spirit is willing but the flesh is weak” type of thing. You WANT to move but your body says “No chance buddy”.

Other people are able to get started but have a hard time staying focused on what they’re doing or just can’t seem to get through a workout. Others are looking to get pumped up even more than what they naturally achieve through weights. Enter the pre workout drink.

Before I dive into pre-workouts I want to comment on nutrition. If you are getting the afternoon nap time grab your teddy bear and snooze feeling around 1 or 2 PM, look at your diet and see if you’re getting enough protein in the morning and some slower digesting carbs both in the morning and around lunch. Protein especially has a stabilizing effect on blood sugar.

Pre Workouts (PW for the rest of the post) are touted as giving you energy and being able to give you incredible pumps. They also claim to give you focus and drive to finish the most intense workouts.

They’ve also been reported to cause dangerous side effects.[1,2]

These news reports discussed a chemical called 1-3 dimethylamylamine or DMAA. This is a form of amphetamine which releases norepinephrine in the central nervous system and may also act as a direct agonist on 5-HT receptors (serotonin) and at higher doses may also release serotonin.

What does this mean? Well it means your brain gets overloaded with a whole bunch of neurostimulants and you feel like talking 1000 words per second, running 3 minute miles and otherwise doing anything and everything in a focused and speedy manner. No bueno.

The good news is that the companies that were making these supplements were ordered by the FDA to stop and destroy them, but just in case here is a list of other names that DMAA goes by:

  • 1,3-DMAA
  • 1,3-Dimethylamylamine
  • 1,3-Dimethylpentylamine
  • 2-Amino-4-methylhexane
  • 2-Hexanamine, 4-methyl- (9CI)
  • 4-Methyl-2-hexanamine
  • 4-Methyl-2-hexylamine
  • Dimethylamylamine
  • Geranamine
  • Methylhexanamine
  • Methylhexanenamine
  • Pelargonium graveolens extract
  • Geranium extract

If you happen to have a PW that contains one of these listed ingredients it is a great idea to throw them out. The reason that amphetamines and other drugs in the same class are Schedule II by the DEA is because of strong addiction potential and abuse potential. You need a prescription from your doc that cannot have any refills by law and fill it at a pharmacy to legally have it in your possession. So yeah.

These are powerful stimulants that can cause serious heart problems. Blood pressure can rise and cause stroke and infarctions in susceptible people. These aren’t to be taken lightly.

Besides the products that have been yanked from the market what about the others that are out there?

PWs are filled with many ingredients. Many are clumped together and then listed as “proprietary blend” which means you don’t know how much of each ingredient is actually present in a serving. Some have brand names of supplements such as CarnoSyn which may impress upon a person that since it’s brand it must be good.

Lets take a look at some of these ingredients and see what they are and what they do.


Looking for that insane "pump"?

Looking for that insane “pump”?

Many PW contain l-arginine or l-citrulline. These are amino acids which help to increase the production of NO or nitric oxide. NO is what is responsible for vasodilation which means that it opens up the blood vessels and allows more blood flow into muscles. Drugs such as nitroglycerin, used for angina, use this principle to open up vessels in the cardiac muscle to relieve chest pain.

Because muscles are able to receive more blood they become engorged and feel inflated or pumped. Anyone who has lifted heavy weights knows exactly what I’m talking about. It does feel as if though your muscles are super tight and huge. It is a pretty cool feeling if I do say so myself.

This is one of the main two reasons people buy PWs. They want that insane pump. Does and increased pump do much for strength or performance?

One study looked at men doing leg extensions with or without a tourniquet. Increases in growth hormone were seen as well as norepinephrine and lactate over controls. While this study doesn’t show strength increases because it was just one round it does suggest that the proper hormones are in place to increase strength such as growth hormone and norepinephrine and lactate. For an interesting article on the history of those you can read this [3].

But that doesn’t tell us about performance. Another study looked at performance in older females (average age 58) and found that occlusion did produce increases in strength and hypertrophy. [4]

In another study rugby players had vascular occlusion of their legs and performed leg extensions compared to controls. Low intensity exercise was performed and after 8 weeks the group with occluded legs had increases in torque during the exercise compared to the other groups. [5]

Another study looking at young male athletes showed similar results. [6] It should be noted the results were small but still significant and resulted in better extension but not flexion.

These studies show that occlusion does help in strength, but what about the actual supplement to increase NO? After all it is thought that if you increase pump it is actually like occluding the muscle because less blood is leaving than entering.

In one study done with ornithine and arginine (ingredients to increase NO) subjects either received these or placebo and were subjected to strength training. The active trial group did gain greater strength than placebo. [7]

In another study in men ages 30-50 who had trained previously were given l-arginine alpha-ketoglutarate vs placebo over 8 weeks. Significant improvement in 1 repetition max bench press was noted but there was no difference in aerobic capacity or body composition. [8] It should also be noted this was a 12g dose/day as 4g three times daily.

Looking at 1 rep max, researchers in Spain found that citrulline was able to increase the number of repetitions done in a placebo crossover design in 41 men. The subjects also reported that they had decreased muscle soreness after 1 and 2 days compared to placebo.[9]

Another study found that after ingestion of l-arginine, 3 sets of 10 repetitions of elbow flexion (curls) and blood volume and total work was measured. The researchers found in this study that blood volume in the muscle did increase, but work performed did not. Muscle oxygenation increased with each subsequent set but was not significant. [10]

The researchers in this last study postulated that no difference was seen in strength because of the exercise protocol used. While many of the other studies looked at protocols to exhaustion or more than 30 repetitions, this protocol was simply 3 sets of 10 separated by 2 min breaks. They were also maximal voluntary contractions (ie no weights). Hard to measure how much more work the biceps might do when the subjects are told to flex hard. It’s almost like seeing how much work a crane can do without attaching any weights and having the operator make it lift “heavier”.

It appears that using a NO precursor such as arginine or citrulline may be beneficial at increasing strength in athletes. Of note, citrulline appears to bypass the liver and be converted in the kidneys to arginine. It has become a popular supplement to replace arginine and doesn’t appear to have the need to be cycled.

The spanish dose used in the above study was 8gm of citrilluine malate. That was around 0.1gm/kg body weight.One study looking at cyclist looked at 6gm citrulline malate 2hrs prior to exercise and growth hormone increased more in this group than in the placebo group as well as enhancing amino acid utilization.[11]

The problem is most PW have 3gm or so. You can triple the dose but you’ll be tripling everything else too and as we’ll see in the next post or two tripling caffeine might not be a good thing.

Another thing to consider is diarrhea. Arginine and ornithine can cause GI upset and diarrhea at doses of 10gm. Some people I’ve read have problems at lower doses. Citrulline has seen no GI upset at 15gm doses, at least in one study. [12] Citrulline appears to be better tolerated on the stomach.

Many who have used these before can attest that some of these PWs can cause severe diarrhea.

My recommendation is that citrulline is a benefit to workouts and strength and endurance, but at the right dose.

Summary Points:

-NO producers such as arginine and citrulline are beneficial in increasing strength

-Citrulline is preferred now over arginine

-Citrulline malate dose is at least 6gm before exercise and probably best taken 45-60 min  preworkout.

-Citrulline appears to benefit fatigue and benefits soreness 1 and 2 days after workout

-Citrulline only has two studies showing real exercise benefit. More evidence is needed to officially say that it indeed helps as an ergogenic aid.

-Arginine does increase blood flow but probably doesn’t increase performance.


Anecdotally I believe citrulline helps me tremendously, but that is my own N=1 and I can’t speak for the general population. If it helps you comment below.

In the next PW article we will discuss beta-alanine.






4. Takarada, Yudai, et al. “Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans.” Journal of Applied Physiology 88.6 (2000): 2097-2106.

5.Takarada, Yudai, Yoshiaki Sato, and Naokata Ishii. “Effects of resistance exercise combined with vascular occlusion on muscle function in athletes.” European journal of applied physiology 86.4 (2002): 308-314.

6.Takarada, Yudai, Tomomi Tsuruta, and Naokata Ishii. “Cooperative effects of exercise and occlusive stimuli on muscular function in low-intensity resistance exercise with moderate vascular occlusion.” Japanese Journal of Physiology 54.6 (2004): 585-592.

7.Elam, R. P., et al. “Effects of arginine and ornithine on strength, lean body mass and urinary hydroxyproline in adult males.” The Journal of sports medicine and physical fitness 29.1 (1989): 52-56.

8.Campbell, Bill, et al. “Pharmacokinetics, safety, and effects on exercise performance of L-arginine α-ketoglutarate in trained adult men.” Nutrition 22.9 (2006): 872-881.

9.Pérez-Guisado, Joaquín, and Philip M. Jakeman. “Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness.” The Journal of Strength & Conditioning Research 24.5 (2010): 1215-1222.

10.Álvares, Thiago Silveira, et al. “Acute l-arginine supplementation increases muscle blood volume but not strength performance.” Applied Physiology, Nutrition, and Metabolism 37.1 (2012): 115-126.

11.Sureda, Antoni, et al. “L-citrulline-malate influence over branched chain amino acid utilization during exercise.” European journal of applied physiology 110.2 (2010): 341-351.

12.Moinard C, et al. Dose-ranging effects of citrulline administration on plasma amino acids and hormonal patterns in healthy subjects: the Citrudose pharmacokinetic study. Br J Nutr. (2008)


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s