Transparent Labs Stim-Free vs Pump: 7 Differences (TESTED)

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I spent a few months testing both of the caffeine-free pre-workouts by Transparent Labs: Stim-Free and Pump.  I’ve written in-depth reviews of each product (here and here). 

But understandably, many readers were left wondering about their key differences and which option was better. 

So, the goal of this article is to compare Transparent Labs Stim-Free vs Pump head-to-head across six categories:

  • Ingredients
  • Advertised Benefits
  • Strength
  • Pump 
  • Energy
  • Taste
  • Cost

If you’re here for a quick answer, Stim-Free is the front-runner if you’re only looking to invest in one product. It provides a wide range of benefits, like strength, energy, and muscle pump.  

That being said, I do appreciate both pre-workouts, and I think they each have merit, depending on how you use them, your goals, and your training. 

Note: If you want to try Stim Free or Pump, I’ve extensively researched the most affordable places to buy them.  If I find better prices, I always update the links below.

Transparent Labs Stim Free

Transparent Labs Stim-Free

Transparent Labs Stim-Free is a great option for lifters who want to optimize strength and performance, but want to avoid the side effects of stimulants like jitteriness or anxiety. The stim-free form is also great for late night exercisers 

Transparent Labs Pump

Transparent Labs Pump

Transparent Labs Pump uses clinical doses for every ingredient that has clinical doses established. This helps guarantee that you will get the advertised benefits.

Key Takeaways

  • Both Stim-Free and Pump are caffeine-free formulas that use clinical doses of high-quality ingredients and are third-party tested to ensure quality and purity. 
  • Stim-Free is a well-rounded formula that boosts energy, strength, power, and endurance. Pump, on the other hand, is specifically formulated to maximize nitric oxide production and muscle pump. 
  • Both formulas cost $1.66 per serving. Similar products on the market, like Swolverine or Gorilla Mode Nitric, cost anywhere from $2.15 to $3.00 per serving, making either of the Transparent Labs formulas a phenomenal value. 

What Is Transparent Labs Stim-Free?

Transparent Labs Stim-Free was one of the pre-workouts I first tested thoroughly for, and it still remains in my top 3 all-time for pre-workout supplements. 

Stim-Free is designed to provide all the key benefits you typically want from a comprehensive pre-workout: strength, pump, energy, and recovery. 

The only difference between Stim-Free and the majority of other pre-workouts on the market is that stim-free provides these benefits without using any caffeine or stimulants. 

This makes it the perfect pre-workout for individuals who want to maximize performance but work out late in the evening and don’t want a high-caffeine pre-workout that might keep them awake. 

It is also a great pre-workout for individuals who are choosing to limit their caffeine intake or are trying to cycle off caffeinated products to reset their tolerance. 

Stim-Free uses clinical doses of some of the most proven pre-workout ingredients, such as citrulline (8g), beta-alanine (4g), and taurine (1.3g). 

Transparent Labs Stim-Free ingredients

The use of clinical doses means that Transparent Labs uses the same quantities of ingredients that have been proven to be effective in research. 

Like all Transparent Labs products, Stim-Free is third-party tested, and the results are available online. This pre-workout does not contain artificial flavors, sweeteners, or colors. 

Transparent Labs Stim-Free costs $1.66 per serving, which is right around the average cost per serving of a pre-workout, which we calculated to be around $1.61. 

Similar high-quality stim-free pre-workouts like Swolverine and Legion Pulse Stim-Free cost more than $2.00 per serving, making Stim-Free an incredible value overall. 

Looking for more?  Read my in-depth Transparent Labs Stim-Free Review here.  


  • Clinical Doses: Using clinical doses means that a company uses the same doses in their products that have been proven effective in clinical trials. This makes it more likely that your pre-workout will actually provide the benefits that it says it will. 
  • Wide range of benefits: Many stimulant-free pre-workouts focus only on increasing nitric oxide production. Stim-Free contains ingredients to improve all aspects of athletic performance like strength, power, pump, energy, endurance, and recovery.
  • Third-Party Tested and Informed Choice Certified: Products that are Informed Choice certified undergo high quality, third party testing. This helps guarantee that your product is safe, effective, and contains no hidden ingredients. 
  • Great Tasting: Stim-Free is available in 7 different, juice-like flavors: Blue Raspberry, Peach Mango, Strawberry Lemonade, Tropical Punch, Orange, Sour Grape, and my personal favorite, Cherry Limeade.
  • Great Value: The combination of high-quality ingredients, third-party testing, clinical doses, and a wide range of benefits makes Stim-Free an incredible value at $1.66 per serving. Similar products on the market cost up to $2.25 per serving.


  • Doesn’t provide noticeable increases to mental focus: This may not be fair because Stim-Free isn’t designed to increase mental focus and alertness. But to be honest, I was hard-pressed to find anything that I didn’t like about Stim-Free.

Who Should Take Stim-Free? 

Transparent Labs Stim-Free is a good option for: 

  • Individuals who prioritize high-quality ingredients and third-party testing to ensure the safety and quality of their products
  • Anyone who works out late at night and doesn’t want caffeine to impact their sleep
  • Lifters who want to maintain athletic performance during a deload week
  • Anyone looking to avoid artificial flavors or sweeteners
  • Someone looking for a clinically dosed product
  • Athletes who undergo drug testing or whose governing bodies require their products to have the Informed Choice certification
  • Someone who has previously had negative pre-workout side effects like jitteriness

What Is Transparent Labs Pump?

Transparent Labs Pump is also a caffeine-free pre-workout, but where Stim-Free provides a Jack-of-all-Trades formula, Pump goes all in on nitric oxide production. 

The Pump formula is simple but effective, with seven key ingredients. 

The key nitric oxide boosters like citrulline and arginine (in this formula as NO3-T ®) provide benefits like muscle pump, increased endurance, and enhanced recovery

Pump also contains two unique ingredients that I hadn’t come across in any other pre-workouts I tested: BioFolate ® and L-Glutathione. 

These two ingredients amplify the body’s ability to boost nitric oxide levels and work really well when paired together with citrulline and arginine.

As a stand-alone product, Pump is going to be the all star in the transparent labs lineup for maximizing nitric oxide production to give you the most intense and noticeable muscle pumps (as the name would suggest). 

Pump is also a great, stackable product, meaning it pairs well with other pre-workouts. 

For example, perhaps you already have a pre-workout that you love for its performance and energy, but you feel like it doesn’t provide noticeable muscle pumps. You can safely take a scoop of Transparent Labs Pump alongside your other product to get the best of both worlds. 

Transparent Labs Pump costs $1.66 per serving. Other clinically dosed nitric oxide boosting pre-workouts like Gorilla Mode Nitric can cost as much as $3.00 per serving. 

When you factor in that Transparent Labs is third party tested, Informed Choice certified, and uses no artificial sweeteners, colors, or unnecessary additives, Pump provides a fantastic value.

Want more info?  Read my in-depth Transparent Labs Pump Review here.  

Transparent Labs Pump


  • Effective Dosing and Ingredients: The main ingredients in the pump have been studied and proven effective in clinical trials. Transparent Labs uses these same doses, ensuring your product delivers on its promises.
  • Pairs well with other pre-workouts: You can easily stack Pump with your favourite pre-workout for a more noticeable pump and better hydration and recovery. 
  • Good Value: Pump costs $1.66 per serving, which is a great value when you consider other pump products on the market can cost up to $3.00 per serving.
  • Third-party tested and informed Choice Certified: Like Stim-Free and all other Transparent Labs products, Pump is third-party tested and Informed Choice Certified, adding an extra level of security regarding the quality and purity of your product. 


  • Not the best tasting: Pump has a noticeably sour taste with a bitter aftertaste. This is common among nitric oxide-boosting pre-workouts since many of the pump-enhancing ingredients are naturally sour or bitter. If you compare the taste of Pump to other nitric oxide boosters, the taste is similar. If you compare the taste of Pump to other pre-workouts in general (like Stim-Free), it’s noticeably less desirable. 
  • Doesn’t provide a wide range of benefits: Pump is a very specialized formula, designed to increase nitric oxide production and enhance blood flow. It does this job very well, but as such it doesn’t provide significant increases to energy, strength, power, or endurance.

Who Should Take It? 

Transparent Labs Pump is a good option for: 

  • Someone looking for the best muscle pumps
  • Someone who values high-quality ingredients and third party testing
  • Someone looking for clinically dosed products
  • Someone who normally experiences jitteriness or anxiety from pre-workout
  • Someone who trains in the evening or wants to avoid caffeine
  • Someone who feels like their main pre-workout isn’t delivering enough muscle pump

Main Differences: Transparent Labs Stim-Free vs Pump


The Winner: Tie

Both pre-workouts are Transparent Labs products. They use the same high-quality ingredients and have clinically dosed formulas. Each formula is well thought out to deliver the benefits it advertises. 

While there is some obvious crossover in the Stim-Free and Pump formulas, you’ll see that Stim-Free uses more ingredients to support strength, power, and endurance where Pump doubles down on nitric oxide boosters. 

Citrulline Malate8000 mg
Beta-Alanine4000 mg
Betaine Anhydrous2500 mg
Taurine1300 mg
L-Tyrosine1000 mg
ElevATP ®150 mg
Senactiv ® (Panax notoginseng)50 mg
Bioperine ®5 mg
L-Citrulline8000 mg
Arginine Nitrate2500 mg
Betaine Anhydrous2500 mg
L-Tyrosine500 mg
L-Glutathione250 mg
Astragin ™50 mg
BioFolate®400 mcg

Key Benefits

The Winner: Tie

Both products deliver on their promises. Transparent Labs Stim-Free is designed to be a complete, well-rounded pre-workout that impacts all areas of athletic performance, whereas Pump (as the name implies) goes all in on supporting nitric oxide production and muscle pump. 

Straight from the mouth of Transparent Labs, Stim-Free promotes a clean and long-lasting focus, drive, and energy, whereas Pump is meant to bolster nitric oxide production, hydrate the body, and enhance blood flow. 

Neither of these advertised benefits are mutually exclusive, though. 

That is to say, if you take Stim-Free, you will still get a muscle pump. 

If you take Pump, you can still see some improvement to strength, endurance, and recovery. 

Which formula is best for you will all come down to which one (athletic performance vs muscle pump) is your priority. 


The Winner: Stim-Free

Transparent Labs Stim-Free comes out on top with a synergistic formula when it comes to increasing strength.

When I tested Transparent Labs Stim-Free, I couldn’t stop raving about how strong and superhuman I felt. 

All of the ingredients in the Stim-Free formula work together to contribute to increased strength. I found that, despite having no caffeine and training late in the evenings after a busy day, I was finishing all of my workouts with energy left in the tank. 

I found myself wanting to increase my weights and push more volume, and I had to consciously remind myself to lower my weights during my deload week. 

One thing that I did notice with Transparent Labs Pump was that, despite not having ingredients directly proven to increase strength, I found that my recovery between sets was better so I was able to hit more reps throughout my later sets when I normally would start to fatigue out.


The Winner: Pump

Though both pre-workouts have nitric oxide boosting ingredients, it probably goes without saying that Pump provided significantly more muscle pump than Stim-Free.

Both pre-workouts contain clinical doses of citrulline, but Transparent Labs Pump is loaded with six additional ingredients that work together to amplify each other’s benefits. 

The end result is a product that absolutely delivers on massive muscle pumps, with nitric oxide levels reaching higher peaks and lasting longer than products that have just one or two pump ingredients. 

I found that Stim-Free did provide a pretty good pump for a general pre-workout, but it definitely didn’t come close to the effects of Transparent Labs Pump. 


The Winner: Stim-Free

Though Stim-Free is a caffeine-free formula, it does contain ingredients to boost mental focus and physical energy.  This provides a great, clean energy without jitteriness or anxiety. 

Stim-Free contains two key ingredients, tyrosine and huperzine, which can impact chemical messengers in the brain and may improve cognitive function and delay fatigue

A patented ingredient called ElevATP ® has been shown in clinical trials to increase levels of ATP (the body’s energy molecule), leading to increases in overall performance. 

Overall, while Stim-Free is a stimulant-free formula, it does still provide enhancements to energy and endurance. 

Pump, conversely, does not contain these same ingredients and won’t have the same effect (but it’s not designed to). 


The Winner: Stim-Free

I found both products to mix reasonably well, but Stim-Free was the clear front-runner regarding taste. 

I found Stim-Free to be really enjoyable, and it’s a product that has made it into my regular repertoire. 

I found Stim-Free to taste very similar to Transparent Labs’ caffeinated pre-workout, Transparent Labs Bulk. (I tried and tasted every single Transparent Labs Flavor, which you can read about here or watch my YouTube video)

I do find that every flavor is a bit sour-leaning, however. 

As discussed above, Transparent Labs Pump doesn’t taste great. 

However, as someone who has tried many nitric oxide-boosting pre-workouts, I do find the taste of Pump to be very comparable, even better than many similar products on the market. 

But when comparing Transparent Labs Pump head to head with Stim-Free, Stim-Free definitely comes out on top.

Currently, Pump is only available in two flavors (Blue Raspberry and Strawberry Lemonade) compared to the seven flavors available for Stim-Free.


The Winner: Tie

Both Stim-Free and Pump cost the same $1.66 per serving. When comparing each product to other similar pre-workouts on the market, they both come in well below the market average. 

The value of the Transparent Labs products is amplified when you factor in other qualities of the brand like third party testing, Informed Choice Certifications, and the decision to forego any artificial ingredients in the products. 

Where To Buy Transparent Labs Stim-Free or Pump

Both pre-workouts are available on the Transparent Labs website, offering a Subscribe and Save feature. 

This allows you to get regular shipments of your favourite products at a discounted rate with free shipping. 

You can also find Transparent Labs Stim-Free on Amazon, but only in two flavor varieties.

What Other Experts Are Saying

  • Matthew Magnante, a senior editor from appreciates both Transparent Labs’ Lean and Bulk pre-workout supplements for their quality and ingredient transparency. He highlights the Lean supplement’s effectiveness for fat burning and energy. He notes the Bulk supplement’s suitability for muscle gain and enhanced performance, citing its higher beta-alanine content. Magnante appreciates the absence of artificial additives in both products. While he doesn’t explicitly favor one over the other, he emphasizes that each supplement offers distinct benefits tailored to different fitness goals. His personal take is positive for both, focusing on their specific functionalities and overall quality.
  • This Reddit discussion summarizes Transparent Labs’ Bulk and Lean pre-workouts. Bulk is recommended for muscle building and strength, while Lean is suited for weight loss and fat metabolism. Bulk enhances muscle pumps and strength, and Lean assists in managing cravings and improving insulin sensitivity. Personal experiences indicate Bulk provides steady energy without anxiety/jitteriness, and Lean effectively supports weight loss. Users choose based on their specific fitness goals: muscle gain with Bulk or weight loss with Lean.


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About The Author

Jennifer Vibert

Jennifer Vibert is a Certified Strength and Conditioning Specialist, Nutrition Coach, and supplement store manager. She has a Bachelor of Kinesiology with a major in Fitness and Lifestyle and a minor in Psychology from the University of Regina. She is a Certified Nutrition Coach through Precision Nutrition, with a passion for helping clients learn the fundamentals of nutrition and supplementation in order to build healthy, sustainable habits.

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I’ve Tested 28+ Pre-Workouts, Here’s My #1 Pick


  • Proven Doses: Ingredients Dosed To Clinical Standards
  • Great Value: 17% Cheaper Than Other Similar Formulas
  • Well-Rounded: Excellent for Pump, Energy, & Strength


  • Proven Doses: Ingredients Dosed To Clinical Standards
  • Great Value: 17% Cheaper Than Other Simliar Formulas
  • Well-Rounded: Excellent for Pump, Energy, & Strength

Read my review