Transparent Labs PreSeries STIM-FREE Review: The Best Stimulant Free Pre Workout Ever?

by Nader Qudimat
Updated November 2, 2021
Release Date
Serving Size
1 Scoop
Only one source
Full profile for strength and stamina enhancement
True disclosed label
Complete nitric oxide profile
Science backed ingredients with clinical doses
Full testosterone and bone health support
Only available at one retailer

Bottom Line

Going caffeine free doesn't mean you need to avoid pre workouts. 

PreSeries STIM-FREE enhances workout performance without using stimulants. 

It's full of ergogenic ingredients that'll not only increase pumps but overall performance as well.

STIM-FREE the perfect pre workout for anyone who wants to make gains and it can increase strength and elevate mood without needing stims.

Stim-Free is completely free of caffeine and stimulants.

Using this pre workout will make cycling off stimulants effortless.

Or it can be used for evening workouts.

You'll great pumps, enhanced focus and improved endurance all while not using a single milligram of stimulants.

For one reason or another, whether you are sensitive to caffeine, or you simply have gone too long without cycling it, Stim-Free is the perfect choice.

The problem with heavy-stimulants is that you're burrowing energy from your future self, hence why you may crash, and have withdrawals that may last for days.

The other pre workouts by Transparent Labs include Lean, a fat burning pre workout, Bulk, a pre workout for gaining muscle, and Stim-Free, basically the same as Bulk but without the stimulants. 

Who Is Transparent Labs?

Transparent Labs is a Utah-based company that grew to a top tier company that produces future-proof supplements.

Stim-free is no different.

This pre workout is the stim-free version of Bulk and contains all the good stuff without the caffeine.

What makes Stim-Free special isn’t the fact that it’s packed and fully disclosed with performance boosters, it’s that it’s been one of the best caffeine free pre workouts for a few years straight.

Without using any trendy or hyped up ingredients, Transparent Labs is able to keep this pre workout in the spotlight for a few years now.

All of their pre workouts are highly rated and praised.

It features a 21 gram scoop packed with performance enhancing ingredients.

And another is that they not only include a testosterone support blend, but also everything is disclosed so you know what you're getting.

Stim-Free Review

I've used Stim-Free quite a few times now and typically I'd take it first thing in the morning. 

First thing that I've noticed is that the scoop is quite big. 

It's like a protein scoop, and it's no wonder seeing how large the servings are. 

Every serving is packed with nearly 23g and it's a completely stimulant free pre workout. 

This means it can be taken anytime and it won't disturb sleep. 

The ingredients are helpful for strength and muscle building as I noticed it has everything needed including beta alanine, betaine and elevATP. 

All of these ingredients have been shown to support muscle and strength in one way or another. 

Of course since it doesn't have stimulants, it wouldn't be fair to rate it's energy but it does have tyrosine and choline, which both support mental function. 

And huperzine A is also included, an ingredient that'll help prolong the effects of choline. 

And that it did. 

I was focused during my workout and long after as these nootropic ingredients can help with mental functions for hours at a time. 

I barely felt the tingles as well from the 4g of beta alanine but I am used to taking beta alanine so my body is probably saturated with it. 

And if you're not, don't worry, it'll take a week or two for the harmless tingles to subside, if it's something you're concerned about. 

What is PreSeries STIM-FREE?

PreSeries STIM-FREE is the exact same as PreSeries Bulk but without the stimulants.

It contains everything needed to make muscle gains and increase performance in the gym but just without caffeine.

This doesn't mean you can't add in your own caffeine source.

This means you can still drink your coffee along with your pre workout or that you can still workout with a pre workout that doesn't have any caffeine.

Why Stimulant-Free?

There are 2 reasons why you'd want to go stimulant-free…

One is that you want to use your own stimulants, maybe caffeine with something else or maybe you're on something like Adderall and can't use any sources of caffeine with it.

You can't take stimulant-based pre workouts on a daily basis without facing some kind of consequences.
The more often you take pre workouts, the more you'll develop tolerance and dependency to use them.

You'll eventually feel drained when you're not using them, your sleep quality will suffer, and you just won't be as motivated to workout as you once were without stimulants.

But if you cycle and control your stim intake, maybe even cut it all out for a short period of time, you'll get hit with the stimulants like the very first time you had them or at least close to it.

And you'll just feel overall refreshed and ready to pump it up at the gym.

Stim-Free Benefits

Compared to other stim-free pre workouts, this one is a bit different.

Transparent Labs has formulated this pre workout to contain ingredients that increases power, improves recovery, boosts endurance, nitric oxide enhancement and testosterone support.

While most stimulant-free pre workout have a simple formula of mainly citrulline and glycerol, Stim-Free has gone above and beyond by covering all aspects of training.

This is an all in one pre workout, no matter if you’re doing cardio, cross fit or bodybuilding, every ingredient is going to help boost nearly every aspect of training. 

Creatine and betaine is at the top of the formula as they both are dosed the highest, and they are heavily researched and backed with studies proving their efficacy.

For endurance and power, beta-alanine is included, and you'll have maximum mental functions thanks to the big doses of nootropics.

Who's It For And Why You Might Not Like It

Anyone who doesn’t want stimulants in their pre workouts will enjoy Stim-Free.

Such a pre workout is very flexible, it can be taken at 12 am and you’d still be able to fall asleep 10 minutes later.

But once you start training, you’ll feel focused and enhanced as this formula is packed with 10 ingredients that are all shown to work well.

As solid as this formula is, there’s not going to be any need to reformulate this pre workout because the ingredients are future-proof and have years (some have decades!) of research and use behind them.

Here's some advantages to using Stim-Free:

Cycling Off Stimulants

Since Stim-Free is completely stimulant free, but yet contains everything else that is needed to increase power, strength, performance and endurance, it is the perfect choice.

Caffeine / Stimulant Sensitivity

If you can’t stand stimulants or are super sensitive to stimulants, Stim-Free is perfect.

Women or Men

The testosterone blend here is only made out of minerals that women should be getting from their diet anyway so there isn’t anything here that makes it only exclusive for men.

Cardio / Endurance Training

Very few pre workouts can be recommended for cardio-based training since most of them contain a high amount of stimulants that would only do more harm than good.

Stim-Free is perfect for cardio training.

How and When To Take Stim-Free

Normally, pre workouts shouldn’t be taken late in the afternoon and should only be used for a short period of time before cycling off.

This is because of the stimulants that are in pre workouts.

Stim-Free is different.

Since it has no stimulants, you guessed it, it can be taken at night, even before you sleep but you might be bothered by the tingles due to the beta alanine.

The nice thing with stimulant-free pre workouts, they can be taken as late or as early, and they still have the same effect.

With Stim-Free, the more it’s taken, the more it can saturate into your muscles.

Ingredients like beta alanine and creatine get better with more usage.

All the ingredients here get better with each use.

Because of this, there’s no reason to cycle off and it can even be taken for years.

If you’re a healthy individual and have taken the “ok” from your doctor on taking supplements with these ingredients, then you’re good to go.

And since the ingredients here are going to optimize and tune your body / muscles, from the testosterone support to the muscle building ingredients, Stim-Free can be taken many hours before your workout.


If you’ve made it this far down, then you know this pre workout is the best caffeine free choice.

It covers all aspects of training and it can work for anyone, from cardio enthusiasts, to crossfit athletes and bodybuilders.

There are 4 major benefits that Stim-Free has and that’s:

  • Strength
  • Muscle growth
  • Endurance
  • High intensity exercise

The long list of ingredients are what makes Stim-Free one of the best, and it hasn’t been formulated for the past few years so you know this is a science-based formula that isn’t about hype.

This is what Stim-Free is made of:

Let’s dig into the ingredients and get into what they really do

Testosterone Support

Update: Stim Free has gone through a revamp and no longer contains zinc, boron or vitamin D3. It does however still contain mucuna pruriens.

There are no other pre workouts that contain a testosterone blend, or if they do then they’ll have prop blend with very few useful ingredients.

Most men and women are deficient in a lot of minerals and vitamins.

Having this issue can be the downfall of your hormone production (for men, it’s testosterone).

Without optimal testosterone levels, muscle building is nearly impossible.

Stim-Free covers this with very effective ingredients, from the best form of Vitamin D3 to Zinc, Boron Citrate and Mucuna Pruriens:

Even women need these minerals so it should be more of a reason to go for a pre workout that has this covered.

Vitamin D3 (3,000IU)

Because of our lifestyles, we have more reasons to get less sunlight. 

From working jobs, schools or just being in the car prevent us from getting enough vitamin D from the sun.

Vitamin D isn’t the most optimal form of supplementation.

It’s bioavailability is poor and you need to have the best form possible to reap the benefits.

Vitamin D3 is the best form to get because of it's bioavailability and there’s a full 3,000IU dose here.

It’s benefits range from bone health, maintaining the immune system and increasing testosterone levels.

Zinc (30mg)

Zinc may as well maybe one of your favorite ingredients.

If you exercise intensely, you're most likely to be low on this.Zinc is one of the most important minerals to have.

You deplete yourself from this mineral as you do any physical activity, and even more when it’s something as intense as lifting weights and sports.

Even stress depletes this mineral.

And when zinc is depleted, testosterone naturally declines.

Research has shown that taking zinc supplements can help increase and optimize testosterone production.
Other benefits include improved endurance, energy, and thyroid levels.

So even if you're just trying to lose weight, zinc plays a vital role in keeping things highly optimized and functional.

Mucuna Pruriens (70mg)

Transparent Labs uses the highest quality ingredients possible, and here they are proving it by using Mucuna Pruriens that’s standardized for 98% L-Dopa.

L-Dopa has research showing it can improve testosterone production and optimizes GH production.

While it’s mainly here for it’s optimization effects on hormones, it can also optimize dopamine production.

It’s a precursor to dopamine, leading to a stress-free and an uplifted mood.

The other benefit is that it can decrease cortisol, leading to optimal testosterone levels.

All in all, for boosting GH, increasing testosterone levels, and improving mood, this is one ingredient that makes the testosterone blend completed.

Boron (5mg)

Boron is another ingredient in this blend that can improve and maintain bone health.

It’s not the only thing it can do.

Studies have shown that this mineral can decrease the sex-hormone-binding globulin, a protein that can decrease testosterone production by binding to it in the blood.

Decreasing SHBG means your body can take advantage of more testosterone, making it an aromatase inhibitor (anti estrogen).

Citrulline Malate (6g)

Stim-Free wouldn’t be complete without some nitric oxide boosters.

And Transparent Labs has done it right with a decent dose of 6g.

Dosages can go as high as 8g, but 6g is the very minimum that we need to see to be happy.

This pump-inducing ingredient is the ultimate version of arginine as it’s much more bioavailable.

It buffers ammonia and lactic acid, letting you have more power in the tank to push through an intense workout while delaying fatigue.

By increasing nitric oxide, it will lead to more strength and power and improving overall athletic performance.

Beta Alanine (4g)

This powerful amino acid, beta alanine, is well known for increasing strength and power output.

Like citrulline, it works by removing and reducing lactic acid in the muscles.

The lactic acid builds up with muscle exertion and physical activity.

By reducing this acid, you'll be able to push harder for a longer period of time before feeling fatigued and you'll be able to lift more.

Since it is an intracellular buffer, it gets better overtime and it tends to saturate the muscles with each use.

The hefty 4g dosage will definitely lead to massive tingles, especially if you’re not used to this ingredient.

Don’t worry though, the tingles are completely harmless and they’ll reduce overtime once you're saturated with beta alanine.

Creatine (3g)

Creatine is one of the most researched ingredients in the supplement industry.

It can help increase ATP production, strength and muscle growth.

This ingredient is easily one of the best and most recommended for guys and girls who have trouble gaining strength and weight.

Since this is combined with Betaine, citrulline and beta alanine, you’ll have decent strength gains and increased workout capacity to do much more than normally.

BCAA's (4g at 2:1:1)

BCAA’s is often used to help prevent muscle loss and improve anabolism.

It’s the building block of muscle protein synthesis.

By stimulating protein synthesis, it can decrease muscle soreness, help with recovery and increase muscle growth.

This means even if you’re on a strict diet with caloric restrictions, BCAA’s here will help you maintain the lean mass you’ve worked hard to get.

Betaine Anhydrous (BetaPure™) (2.5g)

Betaine is a powerhouse ingredient that has been shown in multiple studies to increase muscle protein synthesis, strength and stamina.

It works in synergy with creatine they both enhances the body’s production of ATP.

The clinical dose here makes Stim-Free a powerful pre workout for strength and mass gains.

Taurine (1.3g)

Taurine is a great muscle volumizers that’s highly underrated for its many benefits.

Like glycerol monostearate, it increases muscle size by increasing water in muscles, leading to more “wet pumps”.

It doesn’t make it any less important.

Taurine is found in the heart, brain and skeletal muscle, making it a conditionally essential amino acid.

When it’s combined with creatine, BCAA’s and betaine, it can increase recovery and decrease muscle soreness.

L-Tyrosine (600mg)

Tyrosine is an interesting ingredient and it's one of our favorite non-stimulant energizers. 

It’s mainly used for focus enhancement and improves dopamine production.

Not only can it decrease anxiety and stress, but it acts like caffeine as it can increase alertness and energy.

Choline Bitartrate (500mg)

Choline Bitartrate is a nootropic that’s often combined with other focus enhancers, like caffeine and huperzine A.

Here it’s used to help enhance the mind to muscle connection, improving overall mental focus and concentration.

The 500mg dose is quite enough, although it’s a cheaper version of choline, you’ll certainly feel it’s benefits.

L-Norvaline (60mg)

Now that we’ve covered citrulline, betaine anhydrous, creatine and taurine.

All of these muscle volumizers wouldn’t be completed with a novel N.O. booster like Norvaline.

Norvaline is derived from the amino acid l-valine, it has been shown to increase blood flow and can stop arginase from breaking down, leading to higher nitric oxide levels (thus more and longer muscle pumps!).

ElevATP® (150mg)

When it comes to strength boosting ingredients, you can consider ElevATP to be one of the best for this category.

This is one of the newer muscle building compounds to hit the market.

ElevATP is a combination of ancient peat and a proprietary apple extract. 

It can increase ATP production and power as it shows it can give significant gains in trained men for strength, power and performance. 

BioPerine (5mg)

To help enhance bioavailability and absorption of all the ingredients here, BioPerine is included.

It can help improve digestion of other ingredients and thus maximizing their benefits.

This is definitely a must have in a monster pre workout like PreSeries Stim-Free.

Flavors Available

Although Transparent Labs uses all natural ingredients, for all their supplements, the flavoring improves and the choices grow every so often.

Check out this list:

  • Strawberry Lemonade
  • Sour Grape
  • Orange
  • Blue Raspberry
  • Green Apple
  • Tropical Punch

Future-Proof Pre Workout

A pre workout like this one can’t be cheap but it isn’t more expensive than all the other options out there.

It’s priced at $49.99, but you can knock off $5 with this coupon code FITFREK

You may find cheaper pre workouts but look at their serving sizes and ingredients.

Most of them will either require double serving to get the most out of the ingredients, or won’t even have close to what a pre workout like Stim-Free would have.

If you buy more than one bottle, that’s where the savings really start.

The Way To Workout Without Caffeine

Stimulant free pre’s are no doubt going to be one of the most sought after types of supplements.

Having something like Stim-Free leads to many possibilities, including being able to use your own stimulants or even going completely stimulant-free.

Although Stim-Free is completely natural, it uses top-tier science backed ingredients that leaves this pre workout to be future proof for many years to come.

The benefits range from increased recovery, strength and stamina to much more.

There’s everything to gain and nothing to lose with Stim-Free.

Read up more Transparent Labs supplements here.

by Nader Qudimat

Forged by the iron and cold steel, Nader takes his knowledge and hulks it up into this site.

Having to be stuck as a 110lb skinny guy in the early days, he has had no choice but to keep improving himself until he cannot.

Click here to check out his 12 year transformation: Natural 12 Year Transformation

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