C4 is arguably the most popular pre-workout supplement available on the market today: it has gained huge popularity in various fields of the strength, fitness and physique industry. From bodybuilders and physique enthusiasts to powerlifters, weightlifters, crossfitters and beyond, C4 has achieved serious success and is a top-end competitor in the market. This means that we have to take it seriously and be even more skeptical of its contents and effects – in this article we will provide a comprehensive review of the active ingredients, cost, alternatives and overall value of this supplement.
C4 is an example of the classical, caffeine-based pre-workout that promises to increase preparedness and psychological focus in training and competition. Unlike many pre-workouts – perhaps due to its popularity – C4 relies on a very simple selection of ingredients including common pre-workout ingredients and a number of more surprising compounds. The main focus of the product is the improvement of focus, motivation and performance in training.
As mentioned above, the basis for C4’s effects are the combination of caffeine, Beta-alanine, Creatine and Arginine. All of these have been popular ingredients for pre-workout for years and one of our favorite aspects of the C4 marketing campaign is the reliance on these simple, scientifically-verified ingredients without any of the “snake oils” seen in many other athletic supplements or the associated ‘miraculous’ (unsubstantiated) claims. At first glance, we’re big fans of this product – during this article, however, we’ll discuss the various active ingredients and the overall efficacy of this product.
There are some ways in which we have already highlighted the effectiveness of C4. At the very least, we can say that the ingredients definitely have some of the positive effects that Cellucor advertises: “Explosive energy, heightened focus and an overwhelming urge to tackle any challenge”.
Caffeine has a long history of being associated with increased power output, focus and motivational improvements . Whilst C4 doesn’t discuss the metabolic effects of caffeine, this is also a relevant effect and can be a big benefit to those who are attempting to lose weight [2, 3]. There are some small negative effects associated with the consumption of excessive caffeine – for example, initial studies suggest that there are increased lactic acid build-up in response to caffeine  – but these are generally a product of improved performance or seem to be less significant than their positive counterparts.
Beta-alanine is one of a small number of incredibly effective dietary supplements that actually has some serious positive effects. The consumption of this compound has been shown to improve a variety of performance markers, from muscular endurance to cardio-respiratory capacity and reductions in the perception and effect of fatigue . This final effect can be a great addition to caffeine, which we already saw has some negative effects on the build-up of lactic acid. If caffeine is associated with going harder and being more focused, Beta-alanine is primarily associated with going longer, improving performance in longer sessions and aerobic exercise particularly
Creatine has a long and honorable history among bodybuilders and has been gaining popularity in strength athletes in recent years. Creatine is an essential part of the energy pathways associated with the production of force in short bursts of 0-8 seconds, synthesizing ATP – the body’s main source of fuel. Taken in supplementary doses, creatine improves strength-endurance during long training sessions – whilst it may not necessarily improve strength in the short term, creatine ingestion will reduce the “drop-off” of strength over the duration of a whole training session, increase absolute strength/power output and has protective qualities across the board . Beyond simply improving performance, creatine has a synergistic effect with caffeine, which improves various athletic markers when combined with supplementary creatine intake .
Looking at the basic, active ingredients, L-arginine is perhaps the least important. Arginine has been involved in many dietary supplements with many effects touted, but there have been almost no well-documented effects according to the clinical literature. Whilst arginine has been associated with fat loss, increased aerobic capacity, anti-oxidant properties, insulin/glucose effects and blood flow, it has not been conclusively linked to any of these effects. Arginine is definitely not a bad thing to have in your pre-workout, if even one of the claimed effects is actually borne out practically then it is a seriously worthwhile addition to pre-workout. Even if there is a 1% increase in performance in the claimed effects across the board, this is definitely worth supplementing.
When we look at the reported effects of arginine – particularly in the context of a preworkout – it is important to look at the benefits and risks associated with it. Given that there are no serious negative consequences to taking arginine, we can look at the possible benefits as genuine positives. Simply put, if there are no risks to taking a supplement then possible benefits count for something.
One of our favorite things about C4 – and something that we find appealing in any form of supplement – is a high content of various important vitamins and minerals that have genuine, long-term positive effects on the body’s functions. A single serving of C4 contains 417% of Vitamin C, 150% of B3, 62% of B9 and almost 600% of B12. The B vitamins are bound up in a variety of bodily processes, but perhaps most importantly in the health of tissues and enzymes. These are almost universally important, but they also have an essential function in healthy energy transfer and the metabolism of carbohydrates and fats into glucose and, ultimately, ATP [7, 8]. These vitamins and minerals are not just an attempt of Cellucor to look like a “health supplement” (which would make sense, when Pre-workout supplements have historically been so full of junk), but actually improves performance and overall health in a way that is commensurate with the stated aims of the company and the supplement.
Whist C4 has safe ingredients, there are always concerns when we are consuming stimulants (even caffeine), as some individuals will react more severely than others to the effects. Some reviews have suggested that C4 has resulted in some negative side-effects such as nausea, jitters or chest pains. As ever, it is essential to discuss the consumption of dietary supplements (especially stimulants) with your doctor – especially if you are currently taking any prescription medications.
With that said, it is important to note that the majority of adverse effects were either short-term or not very severe to begin with. Adverse effects are not to be expected from this product – based on the ingredients list, at least – and it should be remembered that these can be associated with any pre-workout product. We do not believe that the evidence bares out any problems with C4 as a pre-workout supplement, but if you do begin to feel any negative side-effects, the best course of action is usually to stop taking the supplement and consult a medical professional to be safe.
The value for money seen in C4 is pretty good: it can be purchased for around $30 from Cellucor’s own website, providing approximately 30 servings. This is a simple $1 per serving cost, making it competitively priced compared to the market alternatives. There are some pre-workout solutions that may work out cheaper than this (foremost among these is simple, home-made coffee), but this product is of a fairly high quality and cheaper competitors don’t generally provide the simplicity and performance that we see with this product. Clearly, C4’s market position and popularity is just as much a result of competitive pricing as it is the result of an impressive product – whilst past iterations have had serious problems, C4 appears to have firmly established itself as a market leader.
One of our most pertinent concerns for any dietary supplement is whether it is meant to replace the role of real food or whether it is a valuable addition to a well-balanced, scientific diet. In the case of C4 there are two major benefits in each of these areas. Firstly, caffeine is not an essential nutrient and thus it is not an attempt to replace anything in the diet: it is not attempting to short-cut the proper nutritional process like many dietary supplements. Secondly, it provides a large quantity of important vitamins which are essential to basic metabolism and – in the case of B12 – provides large quantities of a vitamin that many of us are already deficient in. These additional benefits suggest to us that this supplement can be added to a good diet in a way that adds to the diet without attempting to short-cut the process.
It is rare that we have nothing negative to say about a supplement: pre-workout supplements tend to be full of unnecessary, useless or plainly dangerous chemicals. With C4 this is simply not the case: the product is as simple as it gets and as effective as we can expect from this kind of simplicity. There are no miraculous claims here and the ingredients perform exactly the roles that we might want a pre-workout to play, and then some (when we consider the inclusion of an effective vitamin matrix in the product).
Our overall opinion on this product is one of pleasant surprise: we don’t endorse products often but even amongst alternatives C4 appears to be an excellent choice and can genuinely add value to those who are already on an excellent diet, training and sleep routine. We couldn’t – with good conscience – give this product anything less than a 5.
Related to Cellucor’s C4: Phentaslim Review (New 2020) - Why we rate it as #1
 Doherty et al (2004): ‘Caffeine lowers perceptual response and increases power output during high-intensity cycling’. Journal of sports sciences, pp.637-643
 Yoshida et al (1994): ‘relationship between basal metabolic rate, thermogenic response to caffeine, and body weight loss following combined low calorie and exercise treatment in obese women’. International journal of obesity and related metabolic disorders, 18(5), pp.345-350
 Glaister et al (2014): ‘Caffeine supplementation and peak anaerobic power output’. European journal of sport science, 15(5), pp.400-406
 Hobson et al (2012): ‘Effects of beta-alanine supplementation on exercise performance: a meta-analysis’. Amino acids, 43(1), pp.25-37
 Juhasz et al (2009): ‘Creatine supplementation improves the anaerobic performance of elite junior fin swimmers’. Acta physiologica hungarica, 96(3), pp.325-336
 Lee et al (2011): ‘Effect of caffeine ingestion after creatine supplementation on intermittent high-intensity sprint performance’. European journal of applied physiology, 111(8), pp.1669-1677
 Huskisson et al (2007): ‘The role of vitamins and minerals in energy metabolism and well-being’. The journal of international medical research, 35, pp.277-289
 Watanabe, F. (2007): ‘Vitamin b12 sources and bio-availability’. Experimental biology and medicine, 232(10)
Amanda is a gym instructor and a diet and nutrition fanatic that has reviewed 100s of supplements for the benefit of consumers. She struggled with obesity 7 years ago and after losing more than 30lbs, dedicates most of her time in helping others achieve similar results and transform their lives. You can contact her via the "About Us" page.
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