Pre-workout supplements have become synonymous with the gym lifestyle. If you ask any serious gym goer about their supplement stack, you can pretty much guarantee they will name the big three: protein, creatine, and a good pre-workout.
However, when it comes to pre-workout supplements specifically, there are a couple of things that should be considered.
One of which relates to their stimulant content.
What are stimulants?
Stimulants ultimately describe a broad category of drugs and compounds that increase energy, and can boost mood, heighten mental acuity, enhance focus and attention, and even improve emotional wellbeing.
Moreover, some have even been shown to have potent ergogenic effects, meaning they can enhance exercise performance.
Stimulants can be found in a variety of the foods we consume on a daily basis. However, they are often only consumed in small doses, and consequently only have a small effect on mental and physical performance.
It is for this reason that a number of pre-workout supplements include stimulants in higher doses -- to cause much larger improvement in performance.
Some of the most common natural stimulants include:
- English walnut extract
It is these stimulants that are most commonly used in supplements.
Are stimulants safe?
I first want to preface this section with the caveat that I am talking about LEGAL stimulants here.
There are a variety of illegal stimulants available via various means that impact the body in a very different manner to the legal stimulants found in supplements -- and they are going to be much less safe as a result.
But, with respect to legal stimulants, they are relatively safe for most of the population.
There are certain individuals who may have heart issues or emotional disorders (for example, general anxiety disorder), and therefore may not be safe to take stimulants as it could potentially make their concerns worse.
Moreover, in higher dosages, stimulants can elicit certain side effect, including:
- Jitteriness and restlessness
- Feelings of anxiety and nervousness
- Becoming dizzy and losing balance
- Water retention and bloating
- Nausea and vomiting
- The onset of muscle spasms
Now, it is important to note that these side effects are very rare, and only likely to occur in higher dosages. In fact, in the low to moderate dosages applied in most pre-workout supplements, these are very unlikely to happen.
However, some people are simply more sensitive to stimulants than others -- which is why it is always important to seek advice from a medical professional before commencing supplementation with a stimulant based pre-workout.
One other thing to consider when it comes to stimulants is that they also have the potential to impact upon your sleep. If taken too close to bedtime, they can make it harder for you to fall asleep, while also impacting your sleep quality -- all of which can impact your recovery and the quality of your training.
High-Stim VS Non-Stim pre-workouts
With all this in mind, you might have guessed that the primary difference between high-stim pre-workouts and non-stim pre-workouts comes down to their stimulant content.
High stimulant pre-workouts contain a number of stimulants, while non-stimulant pre-workouts contain none.
This does not mean that one is better than the other, just that non-stim pre-workouts rely on other compounds to improve performance that don't act on the brain and central nervous system in a stimulant-like manner.
While high-stim pre workouts are likely to exhibit a more noticeable effect on mood and energy levels, they may also induce some of the side effects listed above. And of course, they also have the capacity to impact your sleep.
This means that they may not be all that suitable if you typically train later in the afternoon, or are sensitive to stimulants. On the other hand, they could be a great option if you train earlier in the day and are not sensitive to stimulants.
It all depends on you.
Best High Stim Ingredients
If you are after a high stimulant pre-workout that can take the results of your training to the next level, you want to make sure it includes at least two of the following three ingredients.
Caffeine is one of the most effective, and the most well-researched, performance enhancing supplements on the planet. It is known to improve mental alertness, attention, and reaction time, and enhance strength, power, and endurance [1, 2].
With this in mind, it impacts both mental and physical performance in a very big way, and should be a staple in any high-stim pre-workout.
2. English Walnut Extract
English Walnut Extract is a naturally occurring compound that is derived directly from the bark of the English Walnut tree.
This compound is a stimulant that acts directly on the central nervous system, where it boosts energy and mental alertness, improves cognitive function, and promotes the secretion of numerous feel good hormones [3, 4].
As a result it can seriously improve workout performance, causing significantly better training outcomes.
One rather interesting stimulant is N-methyltyramine, which is a powerful compound found in the bitter orange plant.
This particular supplement interacts with the neuroendocrine system, causing the secretion of noradrenaline -- the neurotransmitter that promotes the “flight or fight” response [5, 6].
As a result, it acts as a potent stimulant, increases focus and attention, boosts mood, and vastly improves exercise performance.
Best Non-Stim Ingredients
Now, if you are someone who does not respond well to stimulants, or likes to train in the evening, a non-stim pre-workout is going to be a better option -- and you want to make sure it contains some of these ingredients:
1. L-Citrulline Malate
Citrulline is an amino acid that increases your body's production of nitric oxide. This then increases blood flow to your muscle tissue, which results in a marked improvement in exercise performance [7, 8].
More specifically, citrulline has been shown to increase the number or reps you can perform per set, or the amount of weight you can put on the bar for a given set.
In short, this means more strength and muscle size over the duration of a training block.
Moreover, citrulline has also been shown to speed up recovery after training. This pretty much guarantees that you will get more out of every gym session, which is the integral to long term changes in size and strength.
2. Beta Alanine
Beta-alanine is a unique amino acid that your body uses to produce the compound “carnosine” -- which your body uses to prevent the accumulation of lactate in your muscle tissue.
This ultimately means that beta-alanine allows you to get the most out of your workouts, leading to significant improvements in muscle growth and fat loss.
Agmatine is a neurotransmitter that is found in the cells of your brain. With this in mind, its supplementation has been shown to reduce sensations of pain, while also improving mood and emotional wellbeing [11, 12].
As I am sure you can imagine, this can have a huge impact on exercise performance.
Interestingly, agmatine has also been shown to act in a manner similar to citrulline, where it increases nitric oxide production. This increases blood flow to your muscle tissue, giving you a better pump and speeding up recovery.
Talk about a win-win.
Pre-workouts that contain both high amounts and zero stimulants can offer a myriad of benefits -- which means the choice comes down to which one is better for you.
If you are sensitive to stimulants or train later in the afternoon, maybe opt for a non-stim pre workout option as this will not have any negative effects on your sleep. On the other hand, if you train early in the morning and dont feel sensitive to stims, you can take your pick.
- McLellan, T. M., Caldwell, J. A., & Lieberman, H. R. (2016). A review of caffeine’s effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews, 71, 294-312.
- Grgic, J., Grgic, I., Pickering, C., Schoenfeld, B. J., Bishop, D. J., & Pedisic, Z. (2020). Wake up and smell the coffee: caffeine supplementation and exercise performance—an umbrella review of 21 published meta-analyses. British Journal of Sports Medicine, 54(11), 681-688.
- Liu, Rui, et al. "Small Molecule Oligopeptides Isolated from Walnut (Juglans regia L.) and Their Anti-Fatigue Effects in Mice." Molecules 24.1 (2019): 45.
- Kim, Dae-Ik, and Kil-Soo Kim. "Walnut extract exhibits anti-fatigue action via improvement of exercise tolerance in mice." Laboratory animal research 29.4 (2013): 190-195.
- Camp BJ. Action of N-methyltyramine and N-methyl beta-phenylethylamine on certain biological systems. Am J Vet Res. 1970 Apr;31(4):755-62.
- Koda H, Yokoo Y, Matsumoto N, Suwa Y, Fukazawa H, Ishida H, Tsuji K, Nukaya H, Kuriyama K. Antagonistic effect of N-methyltyramine on alpha2-adrenoceptor in mice. Jpn J Pharmacol. 1999 Nov;81(3):313-5.
- Gonzalez, A. M., & Trexler, E. T. (2020). Effects of Citrulline Supplementation on Exercise Performance in Humans: A Review of the Current Literature. The Journal of Strength & Conditioning Research, 34(5), 1480-1495.
- Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. The Journal of Strength & Conditioning Research, 24(5), 1215-1222.
- Hobson, R. M., Saunders, B., Ball, G., Harris, R. C., & Sale, C. (2012). Effects of ?-alanine supplementation on exercise performance: a meta-analysis. Amino acids, 43(1), 25-37.
- Kern, B. D., & Robinson, T. L. (2011). Effects of ?-alanine supplementation on performance and body composition in collegiate wrestlers and football players. The Journal of Strength & Conditioning Research, 25(7), 1804-1815.
- Keynan, O., Mirovsky, Y., Dekel, S., Gilad, V. H., & Gilad, G. M. (2010). Safety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy. An open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial. Pain Medicine, 11(3), 356-368.
- Shopsin, B. (2013). The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study. Acta Neuropsychiatrica, 25(2), 113-118.