Cellucor C4 Ultimate: An Evidence-Based Review

C4 Ultimate is a pre-workout by Cellucor, the brand behind C4, C4 Ripped, C4 Mass, and about a hundred other renditions of the same basic formula.

Well, we’re pleased to see that Cellucor, a brand which has always seemed to focus more on flashy packaging than making effective supplements, has decided to kick it up a notch and actually do something different this time around.

C4 Ultimate formula is ORDERS OF MAGNITUDE better than any other C4 formula, indicating that Cellucor (owned by Woodbolt International) is looking around at the the supplement industry landscape and realizing that customers are no longer as stupid as they once were.

People want research-backed, clinically-dosed, transparent formulas. The question is…Is does C4 Ultimate meet those criteria? Let’s take a look…

C4 Ultimate


C4 Ultimate Claims/Benefits

The basic claims attached to C4 Ultimate are the same as those attached to just about every Cellucor pre-workout supplements:

  • Focus/Energy
  • Endurance/Strength
  • Recovery

While Cellucor seems to have lightened up on the unrealistic, ambiguous claims, the C4 Ultimate Supplement Facts panel speaks for itself.  Even at a glance it’s easy to see that Cellucor isn’t playing around with this one.  Less marketing, more science…

So, without further ado, let’s dive on in and see what C4 Ultimate is really all about!

C4 Ultimate Ingredients

Some of the ingredients in C4 Ultimate are the same as those found in various other versions of C4, but it also features some rather effective ingredients (at clinical doses) which ultimately make it far superior to anything Cellucor has put out in the past…

Citrulline Malate

Citrulline is both a precursor to Arginine, capable of boosting Nitric Oxide production but is also capable of reducing Ammonia build-up in muscle tissue during exercise, thereby effectively delaying fatigue.

Supplementation with 6g of Citrilline, the same dose found in one serving of C4 Ultimate, has been shown (in multiple studies) to increase the amount of reps performed towards the end of a workout (when fatigue would normally set in), relative to placebo groups.

It’s ultra reliable and is definitely worth using pre-workout to improve your muscular endurance, not to mention Citrulline can provide some pretty nice pumps (due to it’s Nitric Oxide related mechanisms).


Beta-Alanine is the rate limiting amino acid in the production of Carnosine, a depeptide (composed of both Beta-Alanine and Histidine), higher muscular concentrations of which are associated with greater muscular endurance.

This has been studied extensively at this point, with countless studies showing that Beta-Alanine–at doses ranging from 3-6g, typically–can increase muscular Carnosine concentrations and enhance muscular endurance.  This impact is seen in both athletes and amateurs, so basically, everyone can benefit.

In some people, Beta-Alanine can cause a tingling sensation in the skin called Parasthesia.  This is COMPLETELY normal.

Creatine Nitrate

Creatine Nitrate is a form of Creatine–a combination of Creatine and Nitric Acic (Nitrate)–which Cellucor has used before in pretty much every form of C4.

Cellucor’s proposition is that Creatine Nitrate carries the benefits of both Creatine and Nitrates and is also supposedly more bioavailable.  To be clear, there’s no evidence to support those claims.

In fact, a recent 2016 study published in the Journal Of The International Society Of Sports Nutrition found that Creatine Nitrate was similar to Creatine Monohydrate in terms of efficacy.

Unfortunately, that study used 3g of Creatine Nitrate, and C4 Ultimate only contains 1.5g, so it’s tough to say how much it really matters in this instance.


Betaine is naturally occurring in the body but is also found in Beets (where the name originated from) and supplementation has been shown to improve physical performance.

Specifically, betaine can increase strength and power output.  It’s mechanism of action isn’t entirely understood, but it appears to be related to the fact that Betaine is an Osmolyte, meaning it can draw excess water into muscle cells.  This phenomenon is called “cellular swelling“.

C4 Ultimate contains 1.5g of Betaine per serving.  Ideally, we’d like to see 2.5g, since that’s the dose which has been used in most studies, but 1.5g isn’t nothing either.


Nitrosigine is a patented, novel form of Arginine bonded with Silicon–also known as Inositol-Stabilized Arginine Silicate.  The problem with ordinary Arginine is that it isn’t particularly bioavailable.  Much of it is broken down by the enzyme Arginase before it can be converted in Nitric Oxide.

Nitrosigine, on the other hand, is quite bioavailable and has been shown to reduce fatigue, increase blood flow, and enhance recovery in human subjects.

C4 Ultimate contains 1.5g of Nitrosigine per serving, the same dose used clinically to acheive the above-mentioned benefits.

Arginine AKG

Arginine AKG, like Arginine Silicate, is supposedly a novel form of Arginine that is more bioavailable.  In contrast to Arginine Silicate (Nitrosigine), however, Arginine AKG has outright failed to improve exercise performance and shows little promise as a Nitric Oxide booster.

So, we’re really not quite sure why Cellucor is still using it.  C4 Ultimate would actually be better if they just got rid of Arginine AKG and added more Creatine or something.

C4 Ultimate contain 1g of Arginine AKG.  Does it matter though?  Probably not.


Taurine is a unique amino acid with anti-oxidant properties, found in various tissues throughout the body and readily available in protien-rich foods such as Meat and Dairy products.

It’s not likely that you’re deficient in Taurine as long as you’re getting enough protein, but supplementation can still be quite useful if you exercise regularly.

Taurine has been proven to reduce oxidative damage in muscle tissue resulting from exercise.  This has been replicated more than once, making Taurine a reliable recovery-aid in the eyes of science.

C4 Ultimate contains 1g of Taurine per serving, a fairly average dose.


N-Acetyl-L-Tyrosine is allegedly a more bioavailable form of Tyrosine, an amino acid that serves as a precursor to Dopamine and Noradrenaline.

These two neurotransmitters (chemical messengers) are heavily involved in control mood, focus, perceived energy, and motivation so optimizing them is of interest to pretty much everyone.

Here’s the thing though…

Tyrosine does not outright increase levels of Dopamine and Noradrenaline.  It simply serves as substrate for when levels of these neurotransmitters become depleted.  In other words, it can only preserve cognitive function, but cannot enhance exercise or cognitive performance by itself.


Caffeine often form the basis of stimulant-based pre-workout supplements because it reliably triggers the release of  Catecholamines, a group of chemicals including Dopamine and Noradrenaline, which increase levels of pereceived energy and focus.

Put simply, Caffeine provides energy for you to train harder, longer, better, etc…But it also has mechanisms by which it enhances muscular endurance that are not stimulant-releated.

Unlike every other C4 formula, C4 Ultimate contains 300mg of Caffiene per serving.  That’s more than double any of the the other versions and is what most people would consider a fairly strong dose.

Tolerance varies from person to person, but 300mg, especially combined with other stimulant, is more than enough to elicit greater focus, intensity, and energy.

Mucuna Pruriens (L-Dopa)

Mucuna Pruriens, also known as Velvet Bean, as generally standardized for L-Dopa, the intermediate between Tyrosine and Dopamine and the direct precursor to Dopamine.

Tyrosine Dopamine Noradrenaline

L-Dopa, unlike Tyrosine, has actually been shown to increase Dopamine levels which may mean that it can incraese motivation and perceived energy levels while training.  At the very least, it can help preserve cognitive function.

C4 Ultimate contains an unknown quantity of L-Dopa.   Unfortunately, it looks like Cellucor isn’t QUITE ready to let go of proprietary blends completely…


Theacrine, sold under the brand name TeaCrine by Compound Solutions, is a stimulant compound which is similar to Caffeine in a functional and structural sense but appears to be more selective for Dopamine as opposed to Noradrenaline.

Preliminary research (in mice) also indicates it does not cause as much of a tolerance build-up as Caffeine, or at least just not as quickly.

On it’s own, the impact of Theacrine isn’t particularly powerful, but combined with Caffeine it can be useful for enhancing perceived energy and motivation.

Unfortunately, Cellucor provides no indication of how much TeaCrine is present in each serving of C4 Ultimate so it’s difficult to gauge the benefit in this particular case.

Alpha GPC

Alpha GPC is one of the most bioavailable sources of Choline, capable of crossing the blood brain barrier and increasing levels of Acetylcholine in the brain.

Acetylcholine is the neurotransmitter associated with memory, learning, and the mind-muscle-connection, so optimizing levels of it should be interest to anyone looking to maximize power output and muscle contraction force.

It’s the only Choline source that has been shown to increase power output during exercise.  This benefit has bee replicated elsewhere as well.

Unfortunately, C4 Ultimate probably doesn’t contain anywhere near a clinical (600mg) dose of Alpha GPC.  In fact, the only pre-workout we’re aware of that does contain 600mg of Alpha GPC is Catalyst by Momentum Nutrition.


Zembrin is a patented form of Sceletium tortuosum, also known as Kanna.  It’s a South-African plant which has been used traditionally to counteract stress and improve aspects of cognitive function.

Specifically, Zembrin has been shown to act as a 5-HT re-uptake inhibitor which explains the pro-cognitive effects.

Although it remains a speculative ingredient in some sense, it’s an interesting one nonetheless and one which warrants further research.  In the context of C4 Ultimate, it may or may not contribute at whole lot.  We just don’t know at this point…

Rauwolfia Vomitoria

Rauwolfia Vomitoria is generally standardized for Rauwolscine, a potent alpha-adrenergic receptor antagonist which can significantly increase the amount off fat your body burns during exercise.

Rauwoslcine may also have mood-enhancing and pro-sexual effects, like Yohimbine.

Huperzine A

Huperzine A is an Acetylcholinesterase inhibitor, meaning it blocks the enzyme that breaks down Acetylcholine.  Remmeber, Acetylcholine is the neurotransmitter responsible for the mind-muscle-connection and various other aspects of cognitive function.

This makes for a fascinating pre-workout ingredient, but there isn’t much research in that area so far.

Furthermore, we have no idea have much Huperzine A is in C4 Ultimate.

C4 Ultimate Ingredient Takeaway

Well, based on the ingredients, and doses of those ingredients, C4 Ultimate is WAY, WAY, WAY better than any other C4 formula to date.

In fact, Cellucor has been notorious for under-dosing “would-be” effective ingredients but with clinical doses of ingredients like Citrulline, Beta-Alanine, and Betaine, clearly the brand is moving towards a more scientifically-sound approach to formulation.

The Caffeine content of C4 Ultimate is more than double that of most of the other C4 products, so this is no longer a 2-3 scoop product.  1 serving is all you need!

Is C4 Ultimate Safe?

C4 Ultimate does contain some rather unique ingredients, but nothing that can be considered dangerous.  300mg of Caffeine and little Theacrine never hurt anyone…atleast as far as we know.

Does This Mark A Turn-Around For Cellucor?

If you’re familiar with Cellucor (who isn’t) you’ve probably noticed that this is brand that has traditionally spent more time on packaging design than product formulation.

Literally every Cellucor product we’ve ever looked at was under-dosed, so we’re happy to see that, in the case of C4 Ultimate, it’s quite the opposite.

With clinical doses of research-backed, proven ingredients–not to mention a way higher stimulant level–it appears Cellucor has decided to turn the heat up and get competitive again.  The only thing we’ll never understand is the whole “partial transparency”.

Still Not Completely Transparent…

Cellucor does this thing where they disclose the doses of some key ingredients but then hide the doses of the psychoactive/focus/energy ingredients.

We know C4 Ultimate contains 300mg of Caffeine, but we don’t know about NALT, Mucuna Pruriens, Theacrine, Rauwolscine, or Huperzine–all ingredients which could potentially interact with one another, therefore making their doses important.

But whatever.  Baby steps…

Is C4 Ultimate The Best Version Of C4?

Yes.  There is absolutely no doubt about that.  Although Cellucor has rolled out a ton of slightly different versions of C4 including:

C4 Ultimate is way better than all of them.  The rest of the formulas contain far less Caffeine per serving and nowhere near clinical doses of key ingredients on a per serving basis.  If you’re going for C4, go for C4 Ultimate.

The Bottom Line

Cellucor C4 Ultimate is not even comparable to the original C4 or any other version recently released.

For one, it contains about triple the Caffeine content, not to mention a handful of other energy/focus/cognitive ingredients along with highly effective doses of performance enhancement ingredients like Citrulline and Beta-Alanine.

If you’re looking for a pre-workout that will:

  • Provide Some Serious Energy/Focus/Cognitive Enhancement
  • Improve Strength/Endurace
  • Produce Some Nice Pumps
  • Support A Sharper Mind-Muscle Connection
  • Improve Recovery

Then give C4 Ultimate a shot.  Cellucor may be about as commercial as it gets, but clearly this is a brand that realizes the changes occurring in the supplement industry and is willing to follow the science if that’s what the consumer demands. exists to educate the supplement community and seperate the science from the hype.

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