Transparent Labs Lean Review: 60-Day Results (2024)

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I have been using a variety of Transparent Labs products consistently for nearly a year, and have grown to love the brand and the quality of their products (I’ve already raved about their grass-fed whey protein here). 

So I was really excited to put Transparent Labs Lean to the test. 

After two months, I found it provided excellent, sustainable energy throughout my workouts (with no crash), and I definitely felt like I sweated more during my HIIT and cardio sessions.

It fell a little short in some areas, like pump and strength, but that’s because their other pre-workout (Transparent Labs Bulk) is a better fit for those outcomes.

At the end of the day, both Transparent Labs Lean and Bulk should be in your supplement routine, especially if you do both cardio and strength workouts.

I plan to continue using each pre workout products, cycling them depending on the type of workout I’m doing.


Honest Review Guarantee from FeastGood: Our testing team purchases each product 100% independently and uses the product for several weeks up to several months before writing a review. Learn more about our review process here.

Prefer to watch? Our video producer, Matteo, outlines the pros & cons.
  • Transparent Labs Lean is decent value, coming in at $1.66 per serving, which is right around the market average of $1.61 for pre-workouts. 
  • Transparent Labs Lean meets the clinical dose standards for 7/10 of its ingredients according to the latest research.  This means 3/10 ingredients fall short of “optimal” dosing levels (albeit, just slightly short).
  • Transparent Labs Lean is a good option for individuals training exclusively for fat loss or new to pre-workout supplements. Experienced users will likely find this pre-workout a little too subtle.

Overall Rating: 4.0/5

Transparent Labs LEAN
Transparent Labs LEAN


  • Transparent Labs Lean is a caffeinated pre-workout meant to combine both performance enhancing benefits with fat loss


  • Reasonable caffeine level
  • Good taste
  • No artificial ingredients

Best For

  • Someone who values high quality ingredients and third party testing
  • Someone looking to sweat more in their workouts and burn extra fat
  • Someone who is new to pre-workouts and wants something that will provide good energy with a lower risk of side effects
  • Someone who wants a pre workout that isn’t pumped full of caffeine

Medical Disclaimer: The material presented in this article aims to offer informational insights. It should not be perceived as medical guidance. The views and writings are not designed for diagnosing, preventing, or treating health issues. Always consult with your physician prior to starting any new dietary or supplement routine.

What Is Transparent Labs Lean? 

Transparent Labs Lean

Transparent Labs Lean is a caffeinated pre-workout meant to combine both performance enhancing benefits with fat loss. 

It contains common pre-workout ingredients like citrulline malate, beta-alanine, and betaine as well as ingredients to support fat loss like l-carnitine and choline. 

Transparent Labs is known for producing high quality products that are third party tested with publicly disclosed results. 

Lean is no different, containing no artificial sweeteners, colors, or preservatives. 

In its formula, Lean has a lot of patented forms of their ingredients, like Chromas® (Chromium Picolinate), PurCaf® (Organic Caffeine), Bioperine® (Black Pepper Extract), and BetaPure™. 

Patented ingredients have been proven in clinical trials at high standards, often using double blind methods. This guarantees that the products actually elicit the effects that they claim to. 

Transparent Labs Lean is a good option for anyone who is new to pre-workout, since the ingredients that typically cause adverse reactions like caffeine (jitteriness) and beta-alanine (tingling) are in low doses. 

Experienced pre-workout users looking for an intense pre-workout will likely feel that this isn’t strong enough. 

Claims vs Reality:  How I Felt After Taking Transparent Labs Lean? 

Transparent Labs Lean Claims vs Reality

I really love Transparent Labs as a company and the quality of their products, but as someone who has been taking pre-workout for years, I honestly felt like Lean wasn’t as “intense” as what I’m normally used to. 

This may be good or bad depending on your use case (whether you’re a more experienced user or not).

I tested this pre-workout alongside Transparent Labs’ other products: Bulk and Stim-Free, and I found that I had a better pump and strength from those two compared to Lean. 

While I did get an energy boost from this product, I didn’t feel the same mental focus and motivation that I felt when trying the other two Transparent Labs pre-workouts.

I did enjoy using Lean for my cardio and HIIT-based workouts, and I found that I sweat a TON when I used it. 

This pre-workout recommends using 10-12 ounces of water to mix it, which is commonplace for many pre-workouts. Personally, I find this volume of water very uncomfortable to drink right before a workout, so I choose to drink it with 6-8 ounces instead. 

When mixed with the full amount of water, the fruit punch that I tested had a nice strong flavor, but it did have a slightly bitter aftertaste. Despite not being a traditionally “sour” flavor, I found this to be more of a tart flavor as opposed to a sweet one. 

This is common among pre-workouts that don’t use artificial sweeteners. Since the raw ingredients used in pre-workout are often sour or bitter naturally, it can take a lot of sweeteners to mask that taste. 

With only 2g of beta-alanine, this product may still cause skin tingling in some users, but I tend to be very sensitive to beta-alanine and I didn’t notice it at all with this product. 

Transparent Labs LEAN

Transparent Labs Lean

Transparent Labs Lean is a good option for individuals who are training exclusively for fat loss, or who are new to pre-workout supplements. Experienced users will likely find this pre-workout too subtle.

Transparent Labs Lean Ingredients 

IngredientPre-Workout DoseClinical Effective DoseMeets Clinical Standard
Citrulline Malate6000 mg6000-8000 mg
Beta-Alanine2000 mg3000 mg
Betaine Anhydrous1500 mg2500 mg
Acetyl L-Carnitine1000 mg2000 mg
Choline Bitartrate500 mg250 - 500 mg
L-Theanine180 mg200 - 360 mg
Organic Caffeine180 mgn/aN/A
Theobromine50 mgn/aN/A
Bioperine ®5 mg5 mg
Huperzine100 mcg200 mcg

Citrulline Malate

Citrulline is an amino acid that can increase nitric oxide production in the body. In Transparent Labs Lean, citrulline is bound to malic acid – a combination called citrulline malate – which allows it to be more quickly absorbed in the body.

Increased nitric oxide in the body leads to increased vascularity, improved muscle function, and reduced fatigue

For enhancing sport performance, the clinically effective dose of L-Citrulline is 6000-8000mg taken about an hour before exercise. Transparent Labs Lean meets this clinical standard with a dose of 6000mg per scoop.


Beta-Alanine is an amino acid that plays a key role in synthesizing carnosine in the body, and supplementing with beta-alanine can cause an increase in muscle carnosine levels by 15-85%

Carnosine acts as a buffer in the body, which can delay the onset of muscle fatigue. 

In other words, supplementing with beta-alanine can help you exercise at higher intensities for a longer duration or time, increasing total workout volume. 

The clinical dose of beta-alanine is 3000-6000mg and should be taken daily for several weeks to fully saturate the body and see its full benefit.

Transparent Labs Lean falls shy of the clinical dose, offering 2000mg per scoop. 

A common side effect of this ingredient is skin tingling (called paresthesia). With the lower dose found in this product, the effect will likely be unnoticeable to mild for the majority of users. 

Betaine Anhydrous

Betaine is a compound which can be found naturally in foods like beets, spinach, and whole grains. It helps create carnitine in the body, which is a compound that converts fat to energy. 

Betaine shows promise for improving muscle strength, power output, and body composition. The majority of the research shows the most positive benefits being a reduction in fat mass and increase in muscle mass with betaine supplementation. 

The optimal dose for betaine supplementation appears to be 2500mg daily split into two doses of 1250mg throughout the day. Lean Pre-workout does contain 1500mg, but assuming you only take it once per day before your workout, you fall short of the 2500mg clinical dose.. 

Acetyl L-Carnitine

Carnitine is an amino acid in the body which has anti-inflammatory and antioxidant properties. 

Acetyl L-Carnitine is a very specific form which plays a role in fat metabolism, and it can cross the blood brain barrier, which can help to improve memory and mental function. (Though the latter has mostly been studied in older adults and not as much in the physically active population).

The ability for carnitine to convert fat into energy means it can increase fat metabolism, energy, and endurance. 

Carnitine’s ability to help adapt to oxidative stress means it can help reduce exercise-induced muscle damage. 

The clinically studied dose of acetyl l-carnitine specifically falls anywhere from 630-2500mg daily. Lean offers 1000mg, putting it on the lower end of the studied doses, but not below the threshold for clinically effective. 

Choline Bitartrate

Choline is a nutrient that is required by the brain to regulate mood, memory, and muscle control

In regards to taking choline as a pre-workout, it can contribute to increased energy and mental focus, and there is potential that choline plus l-carnitine increase fat breakdown

It makes sense then, that choline and carnitine were used in a product called Lean, which advertises itself as more of a fat loss product. 

In research, doses as low as 250 mg and as high as 2000 mg have been used. Lower doses (250-500mg) are used for general health purposes only, and the typical dose of choline recommended for the mental boost and fat oxidation is between 1000 mg and 2000 mg. 

For a significant performance benefit, Lean falls short of the clinical dose. 


L-Theanine is an amino acid found naturally in tea that can help promote relaxation without causing drowsiness. When paired with caffeine, theanine can improve mental focus and reduce jitteriness (which is a common side effect to taking caffeinated pre-workouts). 

While most studies use 200-400 mg of L-Theanine, it tends to be taken in a dosage of 100-200mg alongside caffeine

In this case, Transparent Labs uses a 1:1 ratio of L-theanine to caffeine, providing 180mg of both. 

Most literature that I could find indicates using a 2:1 ratio of theanine to caffeine. So, for 180mg of caffeine, the recommended dose of L-Theanine would be 360 mg.

Because Transparent Labs Lean falls shy of the 200 mg dose used to study mood and cognitive functions, and doesn’t hit the 2:1 ratio used in exercise-related studies, Transparent Labs Lean doesn’t hit clinical standards for this ingredient. 

Organic Caffeine

What I Like About Transparent Labs Lean

Caffeine acts as a stimulant that speeds up the central nervous system, increases alertness, and can delay the time to exhaustion when taken as a pre-workout. 

As such, it is well documented to contribute to improvements in muscular endurance, strength, HIIT, and cardio performance. 

Caffeine should be taken between 30 and 60 minutes before exercise. While dosing strategies can vary greatly from person to person depending on the frequency of their caffeine intake and their overall tolerance, most pre-workouts fall between 150mg and 400mg of caffeine. 

Transparent Labs Lean is on the lower end of total caffeine, offering up 180mg per serving. While this may be low compared to other pre-workouts, this is still equal to approximately 2 8-oz cups of brewed coffee. 


Theobromine is a stimulant similar to caffeine that is found in kola nuts, tea leaves, and chocolate. 

It offers a longer lasting, calmer energy without the typical spike and crash that can be experienced with other forms of caffeine, like caffeine anhydrous. 

Using a blend of organic caffeine and theobromine will provide a prolonged energy and prevent the effect of a crash that you might experience with other pre-workouts. 

Like caffeine, theobromine may increase cardio and strength performance, as well as energy and mental focus

There is no definitive dose standard for theobromine, with studies ranging from 250mg to 700mg doses. The majority of these studies however were looking at theobromine alone. 

Since Transparent Labs is using theobromine alongside caffeine, my professional opinion is that the dose should be adequate to reduce the crash typically associated with high caffeine pre workouts. 


Bioperine® is a patented form of piperine, or black pepper extract. 

In clinical trials, Bioperine® was shown to increase nutrient absorption by up to 30%. In a pre-workout, this means that Bioperine® can increase how well your other pre-workout ingredients are absorbed. 

The typical dose of Bioperine® is 5-10 mg, so Transparent Labs Lean meets the clinical dosing standard with its 5 mg dose. 


Huperzine comes from Chinese or fir club moss. It can increase acetylcholine levels in the brain, which can help improve memory and cognitive function. 

Because it can increase cognitive function, it’s a common addition to pre-workout supplements. The research, however, isn’t completely sold on whether it’s truly beneficial.

Studies done on Huperzine on humans used a dose of 200mcg before exercise. Transparent Labs Lean offers 100mcg, below the clinical dose.

Highlights: What I Like About Transparent Labs Lean

Pros vs Cons of taking Transparent Labs Lean

Reasonable Caffeine Level 

With 180mg of caffeine plus 50mg of Theobromine, Lean has around 230mg of total stimulants. This amount provides good energy but is low enough that you can stack this with a fat burner, coffee, or energy drinks throughout your day. 

The FDA recommends an upper limit of 400mg of caffeine per day. Transparent Labs Lean contains around half of that, so if you wanted to have other caffeinated beverages throughout the day, like coffee or an energy drink, you can do so without going over the FDA’s limit. 

Good Taste

I tried the fruit punch-flavored Lean and found it enjoyable when mixed with the recommended 10-12oz of water. Lean is available in 10 different fruity flavors. 

Because they don’t use artificial sweeteners, this product does have a slightly bitter aftertaste, which is typical of pre-workouts with high doses of ingredients. 

The ingredients used in pre-workout are naturally sour and bitter, and it can take a lot of flavoring and sweeteners to completely disguise it. 

No Artificial Ingredients

Transparent Labs uses no artificial sweeteners, coloring, or preservatives in their products. 

Transparents Labs also very clearly labels the amounts of other ingredients in their products. The fruit punch flavor of Lean that I tried has 640mg of natural flavors and 490mg of stevia. 

Transparent Labs is gluten-free and suitable for anyone with gluten sensitivities.

Drawbacks What I Did Not Like About Transparent Labs Lean

Not Clinically Dosed

While Transparent Labs does meet clinical dosing on most of its ingredients, it falls short on a few key performance-related ingredients like betaine and theanine. 

For some ingredients which do meet clinical dosing standards, many of the doses fall on the low end, still. 

For example, research around beta-alanine typically uses doses of 3.6g in workout-related studies, with the recommendation being to take a 3-6g daily loading phase for 4-10 weeks, then going into a maintenance dose of 1.2g daily after that. 

If you have been using pre-workout with beta-alanine daily for at least a month, then the dose found in Transparent Labs lean is sufficient for maintenance. If you don’t fall within that criteria, then Lean fails to meet clinical dosing standards.  

Not Super Effective for Pump and Strength

I found Lean to fall short for the pump and strength that I got from the other Transparent Labs pre-workouts, Bulk and Stim-Free. 

For the more experienced user, you may find that the doses in Lean don’t quite provide the pre-workout enhancements that you may have seen with other clinically dosed products. 

If you are new to pre-workout supplements and are shopping for your first one, this will be a good, energizing option that is less likely to elicit the negative side effects associated with pre-workout like nausea, jitteriness, or skin tingling. 

How Does Transparent Labs Lean Stack Up Against Our Criteria For Pre Workouts

Transparent Labs Lean stack up against our criteria for pre workouts


Our rating: 4/5 

Transparent Labs Lean costs around $1.66 per serving (less if you choose a subscribe and save feature on their website). This falls right around the average cost for pre-workout, which is at $1.61 per serving. 

Despite the fact that Transparent Labs falls short a little bit on clinical doses, the product is high quality with no artificial ingredients. 

For the customer who values high-quality, third-party-tested products, Lean provides a great, affordable option. 


Our rating: 4.5/5 

When mixed with 10-12oz of water as recommended, Lean had a decent flavor but did leave a bitter aftertaste. 

I personally find that volume of water uncomfortable before working out, so I concentrated the pre-workout by using only 7-8oz of water. This definitely resulted in a flavor that was more sour and bitter, but still not totally off-putting. 

Because Transparent Labs doesn’t use artificial sweeteners, this product retains some of the naturally sour and bitter properties of the raw ingredients. 


Transparent Labs Lean Mixability 

Our rating: 4.5/5

Lean mixed up easily and completely with little effort. There were no noticeable clumps of product left after mixing if you drink it right away. When left for too long, some undissolved particles will settle on the bottom.  


Our rating: 3.0/5

Lean offers decent mental energy, but I didn’t find it as effective as other pre-workouts when it came to physical energy like muscle strength and endurance.

The addition of Theobromine and L-Theanine, paired with Organic Caffeine, will provide an energy that is slightly longer lasting with a less noticeable crash (or none at all). 

This product is less likely to cause side effects like jitteriness or anxiety with the addition of L-Theanine.


Our rating: 3.0/5

Even though Lean meets clinical dosing standards for citrulline at 6g, I didn’t notice a significant muscle pump with this product. 


Our rating: 3.0/5

Despite the energy boost from the caffeine, I didn’t find Transparent Labs Lean to contribute to significant increases in muscle strength. 

Who should take transparent labs lean

Who Should Take Transparent Labs Lean? 

Transparent Labs Lean is for:

  • Someone who values high-quality ingredients and third-party testing
  • Someone looking to sweat more in their workouts and burn extra fat
  • Someone who is new to pre-workouts and wants something that will provide good energy with a lower risk of side effects
  • Someone who wants a pre-workout that isn’t pumped full of caffeine 

Who Should Not Take Transparent Labs Lean? 

Transparent Labs Lean is not for:

  • Experienced users who are looking for a high stim, high pump product

What Are Other Customers Saying About Transparent Labs Lean? 

In browsing the reviews on the Transparent Labs website, where it has a 4.6/5 star rating, a lot of customers felt the same way I did: it provided a decent boost of energy with no crash, no jitters, and no flushing/tingling. 

Despite its advertising as a fat-burning product, I couldn’t find much feedback from customers about whether they felt it was effective or not. 

The first mention of fat loss that I found was on the 11th page of reviews, where one user reported losing a total of 55lbs over the course of the year, and thought that his workouts wouldn’t have been as prominent without Transparent Labs Lean. 

This product has one of the lowest reviews on Amazon that I have come across, with a 3.8 out of 5 stars. Worth noting is that Amazon has only 108 ratings, where the Transparent Labs website has more than 1700, which makes the Transparent Labs website a more reliable resource. 

What I found interesting is that on the Transparent Labs website, the majority of customers claimed that they thought the product tasted fantastic, across the vast majority of flavors. 

On Amazon, on the other hand, users felt the opposite like this customer who left the following review:  

I’ll start off by admitting that I definitely noticed a more consistent and rapid weight loss in the month that I was using this product, so in my experience, it definitely does what it advertises. However, this is without a doubt the most putrid tasting pre-workout I’ve ever used. Absolutely awful is NOT an exaggeration. I had to mix it with water flavor packets in order to choke it down. This would be my go-to pre-workout if it didn’t taste so terrible.

I suspect that this is because users shopping on the Transparent Labs website are likely more familiar with the product and the fact that they don’t use artificial flavors or sweeteners. It’s more likely as well that those customers are more accustomed to products with fewer flavoring additives. 

Transparent Labs Lean Alternatives?

Transparent Labs Bulk

Transparent Labs Bulk

Transparent Labs Bulk offers a formula similar to Lean, with a few key differences. 

Both products have the same cost per serving, and have the same quality and purity standards. 

Bulk has the upper hand as far as clinical dosing, meeting the high ends of clinical standards for citrulline (8g), beta-alanine (4g), betaine (2.5g), taurine (1.3g), and alpha-gpc (300g). 

Bulk is missing some of the fat loss support that Lean has, like the addition of acetyl-l-carnitine and choline. 

If you are an experienced user who is looking for the best energy and pump possible, I would recommend trying Transparent Labs Bulk to get higher doses of performance-boosting ingredients, while still keeping caffeine at a reasonable level (200mg). 

Bulk has the same L-Theanine added that Lean does, so neither formula should make you feel jitteriness or anxiety. 

Transparent Labs Stim-Free

Transparent Labs Stim Free

If you want the benefits of Bulk or Lean, but you workout late in the evenings or are trying to eliminate caffeine from your day, then Transparent Labs Stim-Free Pre is a great option to try. 

It contains clinical doses of citrulline (8g), beta-alanine (4g), betaine (2.5g), and taurine (1.3g). 

While the stimulants and theanine have been removed, the Stim-Free formula has a patented ingredient called elevATP® which is a patented ingredient that has been shown to increase strength, power output, athletic performance, and reduce fatigue

Like Lean, Stim-Free is third party tested and uses no artificial flavors, colors, or preservatives in its formula. 

All 3 Transparent Labs pre-workouts come in 30 serving containers and have the same cost per serving. 

Are There Any Promos or Discounts For Transparent Labs Lean? 

The Transparent Labs website offers a Subscribe and Save feature, where you can save 10% off your product and get free shipping. 

You can choose to have your product delivered every 30, 45, or 60 days. You can cancel or pause at any time.  

You can also subscribe to the Transparent Labs newsletter to get knowledge of upcoming sales or promotions.

Frequently Asked Questions

Is Transparent Labs Lean The Best Pre Workout?

Transparent Labs Lean is a high quality pre-workout that is good for beginners or people looking for a lower-stimulant option. 

Is Transparent Labs Lean Third Party Tested? 

Transparent Labs Lean is third party tested, with all results available publicly on their website. 

Is Transparent Labs Lean Good For Weight Loss? 

Lean contains a lot of ingredients to support energy and fat metabolism like caffeine, l-carnitine, and betaine. It is a good option to support fat loss goals. 

Is Transparent Labs Lean Safe For Women? 

Transparent Labs Lean is a safe option for women. Do not use Lean if you are pregnant or breastfeeding. 

How Much Caffeine Does Transparent Labs Lean Have? 

Transparent Labs contains 180mg of Organic Caffeine.

Does Transparent Labs Lean Have Creatine?  

Transparent Labs Lean does not contain any creatine. 

How Long Does Transparent Labs Lean Last For? 

Transparent Labs Lean provides a good energy for workouts lasting 45-60 minutes. With L-Theanine and Theobromine in its formula, it is likely to provide longer lasting mental energy with little to no crash afterwards. 

Does Transparent Labs Lean Need To Be Cycled? 

Transparent Labs Lean does not necessarily have to be cycled, but if you find that the product is not providing the same energy and benefits you noticed when you first took it, it’s recommended to take a week or two off. 

Will Transparent Labs Lean Make Me Jittery?

Transparent Labs should not make you jittery. It contains a lower level of caffeine, equal to approximately 2 small cups of coffee. L-Theanine can promote relaxation and mental focus when paired with caffeine, and can counteract the jitteriness effect. 

What Flavors Are Available For Transparent Labs Lean? 

Lean is available in 10 different flavors: Blue Raspberry, Fruit Punch, Sour Peach, Strawberry Lemonade, Green Apple, Orange, Cherry Limeade, Sour Grape, Watermelon, and Tropical Punch.

Where Is Transparent Labs Lean Made? 

Transparent Labs products are manufactured out of Utah in a cGMP compliant facility.  

What Is Transparent Labs Shipping Policy? 

Shipping time varies by country, but can be as fast as 1-3 business days for priority shipping within the USA, and 14-21 business days for international orders. 

What Is Transparent Labs’ Return Policy? 

Returns can be done through customer support ( Your product can be returned within 30 days of purchase if unopened. You can request an exchange or online store credit for items which have been opened. 

How To Contact Transparent Labs?

You can reach Transparent Labs through their customer support number at 1-866-324-9557. 

They can also be reached by e-mail at 

On social media, you can find Transparent Labs active on Facebook, Instagram, TikTok, and Youtube

Transparent Labs LEAN

Transparent Labs Lean

Transparent Labs Lean is a good option for individuals who are training exclusively for fat loss, or who are new to pre-workout supplements. Experienced users will likely find this pre-workout too subtle.


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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