Core Nutrition CORE RX’D Review


  • Optimal dosage of Citrulline Malate (6,000mg)
  • Beta-Alanine can enhance muscular endurance
  • Creatine improves strength & endurance


  • Beta-Alanine also causes a side effect called paresthesia
  • Contains 2 sources of stimulants (increased risk of jitters and energy crashes)
  • Contains ineffective ingredients

See Your Best Options In Our
Top 3 Pre-Workouts Page

CORE-RX'D-Pre-workout container for a leanbulking review

About The Product

CORE RX’D is Core Nutrition’s latest release in 2017. It’s a pre-workout supplement that costs $49.99 for 30 servings and only comes in a ‘Bombsickle’ flavor.

Before we analyze the CORE RX’D’s nutrient profile, we’ll tell you a bit about the company below.

Who are Core Nutritionals? 

Core Nutritionals are a supplements company based in the USA. It was started in the 2000’s and has since sponsored numerous mid-level athletes; such as Kristie Von Wollingen, Taisha Bella & Mike Orta.

But you’re here to learn about CORE RX’D – and we’ll give you everything you need to know in the next section.

CORE RX’D Ingredients Explained

CORE RX’D contains 9 main ingredients, as well as a proprietary blend called ‘Peak O2’. We don’t like proprietary blends, for a number of reasons (which we’ll explain below).


Proprietary blends are mixtures of numerous ingredients that’re only shown to you as 1 quantity. As you can see from the ‘PeakO2’ Blend on its ingredient list, the overall amount is 2g (2,000mg) – but you’re not shown the dosages of each ingredient inside such as Cordyceps.

This increases your risk of side effects, and also makes it uncertain whether this pre-workout will work. For this reason, we try to avoid any supplement that contains proprietary blends.

However, there are some positives; CORE RX’D contains an optimal dosage of Citrulline Malate.

Anyway, we’ll take you through each ingredient in this pre-workout – so you can see how good it really is.


Here’s Everything You Need To Know:

Citrulline Malate 

Great start by Core Nutritionals; Citrulline Malate is one of our favorite pre-workout ingredients, as it improves your muscle pumps in the gym.

Not only that, Citrulline Malate has been optimally dosed here (6,000mg per serving) – meaning it’ll definitely work.

PeakO2 Blend

As we’ve mentioned, this is the proprietary blend inside CORE RX’D. It contains 6 different types of mushrooms believed to promote improve your strength and sporting performance.

Anyway, we’ll give you a brief overview of each nutrient inside this blend:

  • Cordyceps Militaris – A traditional mushroom used in traditional Chinese medicine, it’s believed to regulate testosterone production and improve your general health. However, there hasn’t been any study to prove it improves your gym session.
  • Ganoderma Lucidum – This is thought to improve your immune system and reduce stress. While it’s shown to reduce fatigue in 1 study, this result isn’t reliable.
  • Pleurotus Eryngii – Also known as ‘King Oyster’, this is thought to boost your immune system too. However, people have known to be allergic to this ingredient (meaning it’s not a good idea to add to supplements like CORE RX’D).
  • Lentinula Edodes –  More commonly known as ‘Shiitake mushroom’, it’s used in Japanese cooking. However, while it can improve general health, it hasn’t proven to enhance your gym session.
  • Hericum Erinaceus – Also called ‘Lion’s Mane mushroom’, it’s shown to enhance your cognition. But as it doesn’t improve sporting performance, we believe it’s better suited in Nootropic supplements.
  • Trametes Versicolor – You’ve probably guessed…this is another mushroom. It’s believed to improve your immune system, but hasn’t shown to enhance your gym session (making it an ineffective ingredient in CORE RX’D).



This ingredient always splits opinions on the LeanBulking website. Simply put, Beta-Alanine has shown to enhance muscular endurance – but it’s also shown to cause a side effect called paresthesia.

Basically, paresthesia is a tingling and itching on the skin of your face and body. Personally, we don’t like this side effect as we can’t concentrate on our gym session while suffering from paresthesia.

For this reason, we try to avoid pre-workouts containing Beta-Alanine; however, we never criticize a supplement just for this ingredient, as we accept others don’t mind this side effect as much as us.


Taurine is an organic acid containing sulfur (not bull’s urine, like some believe). However, it’s also mistakenly thought to boost your energy, as it’s contained in popular energy drinks.

It offers 1 benefit – reducing your cramping in the gym. However, as this benefit is achieveble from simply drinking enough water, we don’t think Taurine is needed in pre-workout supplements.


This is one of the worst ingredients you can find in pre-workout supplements. Simply put, it’s known to cause a strange side effect – causing you to have fishy breath and sweat.

Not only that, Betaine hasn’t shown to offer any benefits in any studies conducted on it. This means Betaine is a useless ingredient that causes a side effect.


Creatine HCL 

Creatine can be a key ingredient in any pre-workout; it’s proven to boost your strength and endurance in the gym.

However, there are different forms of Creatine, and the one inside CORE RX’D is Creatine Hydrochloride; while this is believed to be more water soluble, it’s not as reliable as Creatine Monohydrate (which has been used since the 1980’s.

For this reason, we’d choose Creatine Monohydrate everytime instead. Unfortunately, Core Nutritionals chose Hydrochloride here.


This is a cholergenic compound that’s believed to improve your cognition. However, it’s also shown to cause numerous side effects – which is why we try to avoid supplements containing Alpha-GPC (see side effects section for more info).


Caffeine Anhydrous 

Caffeine is the best stimulant you can find in any pre-workout supplement. It’s proven to improve your strength, endurance, focus and energy levels – all key benefits to enhance your gym session and help you make gains.

However, consuming large dosages of Caffeine can cause jitters and energy crashes (which is why many pre-workouts are known for causing these side effects).

As CORE RX’D contains 250mg, this is on the border of being a safe dosage. Those sensitive to Caffeine might suffer from jitters and energy crashes, but those who drink over 4-5 coffee’s a day should be okay.

Personally, we prefer Caffeine dosages under 200mg per serving; this is safe for everyone, while providing benefits to improve your gym session.


This is another stimulant that’s believed to offer similar benefits to Caffeine. But here’s the problem; there hasn’t been as much studies conducted on Theacrine (so it’s not 100% certain whether it’s safe or effective).

For this reason, we’d choose Caffeine everytime – but there’s another problem. As RX’D already contains Caffeine, there’s no need for more stimulants.

Ultimately, this increases your risk of suffering from jitters and energy crashes.


This is a mixture of 2 ingredients – Astragulus and Notoginseng. All you need to know about this ingredient, is that it hasn’t shown to benefit your gym session in any studies (making it an ineffective ingredient in RX’D).

We would’ve preferred to see a useful ingredient, such as L-Carnitine instead.

Three containers of CORE RX'D Pre-workout lined up next to each other for a leanbulking review

See Your Best Options In Our
Top 3 Pre-Workouts Page

Side Effects

There are 3 things that can cause side effects in CORE RX’D – Beta-Alanine, Alpha-GPC & the overdose of stimulants.

Simply put, Beta-Alanine can cause paresthesia, which is a tingling and itching sensation on your face and body. Alpha-GPC can cause numerous side effects (which we’ll list below), and the over-dose of stimlants can cause jitters and energy crashes.

For this reason, we can’t recommend CORE RX’D to you. There are many safer and more effective pre-workouts available on the market.

Here’s the potential side effects from taking CORE RX’D: 

  • Paresthesia (Beta-Alanine)
  • Heartburn (Alpha-GPC)
  • Headache (Alpha-GPC)
  • Insomnia (Alpha-GPC)
  • Jitters (2 stimulants in 1 pre-workout)
  • Energy Crashes (2 stimulants in 1 pre-workout)

CORE RX’D Review Conclusion

Core Nutritionals are a respected brand in the supplements industry. However, they’ve made some rookie errors when formulating this pre-workout, CORE RX’D.

Simply put, it’s never good to have more than 1 stimulant in a pre-workout (with Caffeine being the safest option when dosed under 200mg per serving).

Not only that, they’ve added a proprietary blend full of mushrooms that haven’t shown to benefit your gym session…This was never a good idea.


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