We test and review fitness products based on an independent, multi-point methodology. If you use our links to purchase something, we may earn a commission. Read our disclosures.

For this Transparent Labs LEAN Review, we had Olympic lifter Caine Wilkes, OLY, USAW-L1, and GGR senior staff writer test it out. We’ve tried the grass-fed whey protein from Transparent Labs before, so we had to see what their fat burner pre-workout was all about. 

RELATED: Transparent Labs Protein Review

The active ingredients in Transparent Labs preseries LEAN are, according to the company, “developed for a single purpose: to be the most exceptional cutting pre-workout supplement, ever.” Were they successful? Let’s see what Caine had to say. 

Medical disclaimer: This article is intended for educational and informational purposes only. It is not intended as a substitute for medical advice. For health advice, contact a licensed healthcare provider. GGR also recommends choosing a product that has been third-party tested for quality.

Personally Tested, Honestly Reviewed Supplements

The fitness professionals, dietitians, and personal trainers on our team personally order, open, use, and rate the supplements we test to provide you with a comprehensive picture of what to expect. Our rating is based on our GGR supplement testing methodology. For supplements, we give products a 1-5 rating based on:

  • Quality of the Formulation
  • Taste/Solubility
  • Side Effects
  • Third-Party Testing
  • Price/Value
  • Customer Reviews/Service

We rate supplements based on what research has shown about their ingredients, the expertise of our testers, and our honest experiences with them.

Transparent Labs LEAN Pre-Workout

GGR Score: 4.16 starstarstarstarstar

Product Highlights

  • Formulated for those looking to lose weight but maintain muscle mass
  • 14 grams of evidence-based ingredients
  • Naturally flavored and sweetened with Stevia
  • Available in 9 different flavors
  • Backed by a 60-day money-back guarantee

Pros & Cons


  • Includes vitamins/micronutrients to support thyroid production
  • High levels of citrulline to increase oxygen delivery to muscles
  • No artificial sweeteners
  • No artificial colors
  • 60-day money-back guarantee


  • Bitter and unpleasant taste for some consumers
  • Several reports of receiving wrong item

Bottom Line

Transparent Labs’ LEAN pre-workout supplement promises to deliver better endurance, power, alertness, and focus. The fat loss component is less of a guarantee with few reports of an actual change in body composition.

A Quick Look at Transparent Labs LEAN

Transparent Labs products have a reputation for being some of the most high-quality stuff out there. They consistently offer third-party tested protein powder and other supplements with clinically effective doses that are free of artificial sweeteners, artificial colors, and proprietary blends. 

Though PreSeries LEAN is formulated for cutting, there’s also the PreSeries Transparent Labs BULK pre-workout with active ingredients to support weight gain from muscle mass. 

Before You Buy

  • Though advertised as a fat-loss supplement, you may only want to take it pre-workout as the caffeine content could give you jitters during unwanted times.
  • There is a Transparent Labs stim-free pre-workout, but it lacks the fat-burning ingredients.
  • Fat loss from fat burners is still limited in research, so try it with tempered expectations.

Is Transparent Labs LEAN Worth It?

This pre-workout is great for those cutting for fat loss, as it contains active ingredients that may help improve body composition while supporting exercise performance through better blood flow and an energy boost. However, it would be a lot closer to the “best pre-workout for cutting, ever” if it had branched-chain amino acids to help preserve muscle mass, especially considering the price is a tad steep at $1.67 a serving. 

Great for:

  • People working out on a calorie deficit who may be low on energy as a result
  • Those looking for a clean pre that may help with their body composition
  • Athletes who want a low-calorie pre-workout

Not recommended for:

  • Those on a budget looking for a cheap pre-workout
  • People who are sensitive to caffeine anhydrous
  • Individuals actively trying to put on muscle mass 

Transparent Labs LEAN Specs

Price per serving$1.67
Serving size1 scoop (14.2 g)
FlavorsStrawberry Lemonade, Fruit Punch, Sour Grape, Sour Peach, Cherry Splash, Blue Raspberry, Green Apple, Orange, Tropical Punch
Caffeine dosage180 mg
Creatine dosageNone
L-Citrulline dosage6 g
Beta-alanine dosage 2 g
Other key ingredientsBetaine Anhydrous (Betapure), Choline Birtartrate, L-Theanine, Theobromine, Bioperine (black pepper extract)
Third-party Tested?Yes, Informed Choice
BenefitsMay help with fat burning, boost exercise performance, and delay muscle fatigue

Experience Using Transparent Labs LEAN

“I used TL LEAN multiple times per week while I was training for an international weightlifting competition,” says our tester Caine Wilkes, OLY, USAW-L1, and GGR senior staff writer. “The workouts I did were Olympic lifting and strength training workouts involving snatches, clean and jerks, squats, presses, and pulls. “

Caine Wilkes is shown mixing a batch of Transparent Labs Pre-Workout.

Caine also liked the energy and focus. “I’m pretty sensitive to caffeine, so 180 milligrams of caffeine per serving was enough to boost my energy. There were several days where I didn’t feel super motivated to hit the gym but the boost of energy this product gave me helped. It helped with focus, too, and I didn’t experience any significant crash after the workout was over either.”

RELATED: Best Pre-Workout for Focus

Price Per Serving

We rated Transparent Labs LEAN 2.75 out of 5 for a price of $1.67 per serving, which is a bit high compared to the market average. However, the inflated price tag is likely due to a couple of extra ingredients thrown in to promote weight loss, third-party testing, and an overall high-quality brand. 


We gave it a 2 out of 5 for formulation due to it containing no creatine, under-dosed beta-alanine, and less than 200 milligrams of caffeine. It’s also advised to take a half scoop to test tolerance when you start, which would also result in you getting shorted on dosages until you get adjusted. 

Citrulline Malate (6 grams): Helps increase blood flow to muscles by boosting nitric oxide, and its clinically effective dose to achieve this effect is 6 to 8 grams1, so Transparent Labs passes the test.

Beta-Alanine (2 grams): Pre-workout ingredients often include beta-alanine as research suggests it can help you lift more weight2 during high-intensity training. However, the effective dose is 4 to 6 grams3 and Transparent Labs LEAN pre-workout contains only 2 grams per serving. 

Betaine Anhydrous (as Betapure) (1.5 grams): There has been some evidence to suggest that supplementing with betaine anhydrous for 15 straight days can help improve muscular endurance4.

Acetyl L-Carnitine HCl (1 gram): So here’s the thing. The Transparent Labs website says this ingredient (abbreviated ALCAR) “upregulates dopamine receptor expression and protects against neurodegeneration,” which I guess is just a fancy way of saying it helps improve cognitive function. 

Looking down on a scoop of Transparent Labs Pre-Workout as it's being lifted from the container.

However, the study5 they cite was done on rats and we couldn’t find these results in humans. Whatever the case, l-carnitine promotes recovery and helps decrease fatigue in lean muscle tissues, according to human studies6.

BioPerine Black Pepper Fruit Extract (5 milligrams): Known as bioperine, black pepper extract is increasingly found in sports nutrition supplements due to its ability to help increase the absorption7 of natural substances, like creatine and tyrosine.

Other ingredients: It also includes 1.5 grams of betaine anhydrous, 180 milligrams of theanine, 50 milligrams of theobromine, and 100 micrograms of Huperzine A. 

It would also be nice to see some branched-chain amino acids (BCAAs) in this pre-workout supplement as studies have shown that they can help preserve lean muscle and even assist with fat loss during a cut or calorie deficit8

RELATED: Best Pre-Workout With BCAAs

Taste and Solubility 

We gave a rating of 4.5 out of 5 for taste as Caine thought the flavor was OK after trying the sour grape. “If I’m being picky, the flavor was more sour than grape, but it wasn’t an unpleasant flavor,” he said 

He also appreciates the lack of artificial sweeteners: “It’s not overly sweet, and it doesn’t have an overpowering stevia flavor, which is nice. I think many people will appreciate the use of stevia and lack of artificial flavors in the pre-workout as well.” 

RELATED: Best Pre-Workout for Weight Loss

A clear glass containing a pink dose of Transparent Labs Pre-Workout is shown next to the container.

For solubility, we gave it a rating of 4 out of 5 based on Caine’s experience. “I used a shaker cup for the majority of my workouts, and it mixed well enough, though not perfectly. There were usually a few granules at the bottom of the cup when I finished drinking,” he said.

Side Effects

We gave it a rating of 5 out of 5 in this category as Caine did not experience any adverse side effects, but did get some jitters due to his tolerance. “As I’ve said before,” Caine notes, “I am sensitive to caffeine, so there was a workout or two where I felt a little jittery at first, but that was all, and it wasn’t every workout.”

Third-Party Testing 

We gave it a 5 out of 5 here as, like most Transparent Labs products, Transparent Labs LEAN pre-workout is certified by Informed Choice, a third-party lab that sports organizations recognize as being sufficient in testing sports supplements for safety and potency. Since pre-workout supplements are not approved by the FDA, third-party testing is the best way to assess safety. 

Transparent Labs LEAN vs XWERKS Ignite Pre-Workout

XWERKS Ignite and LEAN pre-workout have very similar formulations, despite LEAN being more heavily marketed for fat loss. Both are also close in price, lack creatine, and neither has the effective dose of beta-alanine. 

What Transparent Labs has that XWERKS does not is slightly more caffeine, more flavors, twice as much l-citrulline, and, most importantly, is third-party tested. XWERKS is also sweetened with sucralose, an artificial sweetener. 

To learn more, check out our full XWERKS Ignite review.

Transparent Labs LEANXWERKS Ignite Pre-Workout
Price per serving$1.67$1.63
Serving Size1 scoop (14.2 g)1 scoop
FlavorsStrawberry Lemonade, Fruit Punch, Sour Grape, Sour Peach, Cherry Splash, Blue Raspberry, Green Apple, Orange, Tropical PunchGreen Apple, Orange, Blue Raspberry, Watermelon
Caffeine dosage180 mg150 mg
Creatine dosageNoneNone
L-Citrulline dosage6 g3 g
Other key ingredientsBetaine Anhydrous (Betapure), Choline Birtartrate, L-Theanine, Theobromine, Bioperine (black pepper extract)Calcium-Lactate Gluconate, Pyridoxine HCl, Caffeine Anhydrous, Rhodiola rosea, DMAE Bitartrate, L-Tyrosine
Beta-Alanine dosage2 g1.5 g
Third-Party Tested?Yes, Informed ChoiceNo
BenefitsMay help with fat burning, boost exercise performance, and delay muscle fatigueMay help with muscle growth, endurance, and mental focus

Customer Experience 

We gave a rating of 5 out of 5 here as we had no issues with customer service and Transparent Labs is known for being responsive via email contact at support@transparentlabs.com or by phone at 1-866-324-9557. 

A black shaker bottle rests next to a container of Transparent Labs Pre-Workout.

For a refund, you must email transparentlabs.com within 30 days of receiving your pre-workout supplement, and the product must be unopened. Store credit or exchange may be available if opened.

Ordering Transparent Labs LEAN

When ordering from Transparentlabs.com, shipping is free for orders over $100. Otherwise, standard 5- to 7-day U.S. shipping is $7.99. You can also get free shipping and a 10% discount by enrolling in Subscribe & Save, which you can schedule for delivery every 30, 45, or 60 days.

RELATED: Best Pre-Workout for Beginners

Customer Reviews

We gave a rating of 4.6 out of 5, the same average on the Transparent Labs website based on 2,012 reviews at the time of writing. Not many users commented on its effectiveness for weight loss, but most love the energy it gives and that it’s free from artificial colors, preservatives, and other additives. 

On Amazon, Transparent Labs Lean Pre-Workout is rated 4.1 out of 5 stars based on 161 pre-workout reviews. Many people love how clean the product is, but others complain about the cost and taste. 

Final Verdict of Transparent Labs LEAN Review

We appreciated the combo of pre-workout ingredients like nitric oxide boosters and fat loss compounds, but think the formulation is still a little lacking to be worth the price. However, for those looking for a pre-workout that’s clean and low-calorie enough to be suitable for cutting, it may be worth a try. 

  • Pricey compared to pre-workouts with a similar formulation
  • Third-party tested with clean ingredients from a trusted brand

Full Rating

Transparent Labs LEAN Pre-Workout

Transparent Labs’ LEAN pre-workout supplement promises to deliver better endurance, power, alertness, and focus. The fat loss component is less of a guarantee with few reports of an actual change in body composition.

Product Brand: Transparent Labs

Product Currency: $

Product Price: 49.99

Product In-Stock: InStock

Editor's Rating:

Transparent Labs LEAN Ratings

Price per serving – 2.75
Ingredients and formulation – 2
Taste – 5
Solubility – 4
Side effects – 5
Third-party testing – 5
Customer service – 5
Customer reviews – 4.6
Buy Now

Transparent Labs LEAN: FAQs

What does Transparent Labs Lean do?

Transparent Labs LEAN pre-workout contains both pre-workout ingredients and fat burners to support high-intensity exercise and a more optimal body composition. 

What is the best fat-burning pre-workout?

There are a lot of great pre-workouts to try if your goal is fat loss. Here are our top picks in a variety of categories from our best pre-workouts for weight loss list:

-Best Overall Pre-Workout for Weight Loss: Transparent Labs LEAN
-Best Pre-Workout for Women’s Weight Loss: Legion Pulse
-Best Pre-Workout for Men’s Weight Loss: XWERKS Ignite 
-Best Pre-Workout for Weight Loss and Muscle Gain: Kaged Pre-Kaged
-Best Pre-Workout for Weight Loss for Beginners: Jacked Factory Nitrosurge
-Best Natural Pre-Workout for Weight Loss: Onnit Alpha Brain
-Best Pre-Workout for Running and Weight Loss: MyProtein THE Pre-Workout
-Best-Tasting Pre-Workout for Weight Loss: Huge Supplements Pump Serum
-Best Non-Stim Pre-Workout for Weight Loss: Genius Pre
-Best Pre-Workout for Weight Loss for Athletes: 1st Phorm Endura-Formance
-Strongest Pre-Workout for Weight Loss: Transparent Labs Bulk Black

What’s the difference between Swolverine and Transparent Labs?

Swolverine Pre is also a gluten-free supplement with no artificial colors, sweeteners, or preservatives, but is not third-party tested like Transparent Labs. 

How long does pre-workout last?

The duration of a pre-workout supplement’s effectiveness depends on your individual metabolism. The ingredients used will also play a large role in how long a pre-workout lasts, but the average pre-workout will typically last somewhere between 30 minutes and 2 hours. 

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any diseases.


  1. Gough LA, Sparks SA, McNaughton LR, Higgins MF, Newbury JW, Trexler E, Faghy MA, Bridge CA. A critical review of citrulline malate supplementation and exercise performance. Eur J Appl Physiol. 2021 Dec;121(12):3283-3295. doi: 10.1007/s00421-021-04774-6. Epub 2021 Aug 21. PMID: 34417881; PMCID: PMC8571142.
  2. Hoffman J, Ratamess NA, Ross R, et al. Beta-alanine and the hormonal response to exercise. Int J Sports Med. 2008;29(12):952-958. doi:10.1055/s-2008-1038678
  3. Trexler ET, Smith-Ryan AE, Stout JR, et al. International society of sports nutrition position stand: Beta-Alanine. J Int Soc Sports Nutr. 2015;12:30. Published 2015 Jul 15. doi:10.1186/s12970-015-0090-y
  4. Hoffman JR, Ratamess NA, Kang J, Rashti SL, Faigenbaum AD. Effect of betaine supplementation on power performance and fatigue. J Int Soc Sports Nutr. 2009;6:7. Published 2009 Feb 27. doi:10.1186/1550-2783-6-7
  5. Singh S, Mishra A, Srivastava N, Shukla R, Shukla S. Acetyl-L-Carnitine via Upegulating Dopamine D1 Receptor and Attenuating Microglial Activation Prevents Neuronal Loss and Improves Memory Functions in Parkinsonian Rats. Mol Neurobiol. 2018;55(1):583-602. doi:10.1007/s12035-016-0293-5
  6. Koozehchian MS, Daneshfar A, Fallah E, et al. Effects of nine weeks L-Carnitine supplementation on exercise performance, anaerobic power, and exercise-induced oxidative stress in resistance-trained males. J Exerc Nutrition Biochem. 2018;22(4):7-19. doi:10.20463/jenb.2018.0026
  7. Khajuria A, Thusu N, Zutshi U. Piperine modulates permeability characteristics of intestine by inducing alterations in membrane dynamics: influence on brush border membrane fluidity, ultrastructure and enzyme kinetics. Phytomedicine. 2002;9(3):224-231. doi:10.1078/0944-7113-00114
  8. Ooi DSQ, Ling JQR, Ong FY, et al. Branched Chain Amino Acid Supplementation to a Hypocaloric Diet Does Not Affect Resting Metabolic Rate but Increases Postprandial Fat Oxidation Response in Overweight and Obese Adults after Weight Loss Intervention. Nutrients. 2021;13(12):4245. Published 2021 Nov 26. doi:10.3390/nu13124245

Further reading

MX Select Adjustable Dumbbells Review (2024): Selectorized and Compact Dumbbells Cover Image
MX Select Adjustable Dumbbells Review (2024): Selectorized and Compact Dumbbells

In this MX Select Adjustable Dumbbells review, I’ll detail what I like, and warn you about things I don’t. Read more

Purple Carrot Review (2024): Fresh and Convenient Plant-Based Meals Cover Image
Purple Carrot Review (2024): Fresh and Convenient Plant-Based Meals

Find out if this plant-based meal delivery service is right for you with our Purple Carrot review. Read more

Xero Shoes Speed Force Review (2024): Good Performance From Their Updated Racing Shoe Cover Image
Xero Shoes Speed Force Review (2024): Good Performance From Their Updated Racing Shoe

Xero Shoes has made their lightest running shoe yet with their new updated barefoot shoe. See our thoughts in our Xero Shoes Speed Force review. Read more

How Much Does a Home Gym Actually Cost in 2024 Cover Image
How Much Does a Home Gym Actually Cost in 2024

So you want to build a gym at home, but you're not sure how much you should expect to spend. You're not alone; this is by far one of the most asked questions we receive. We've detailed just how much you can expect to spend and believe it's likely much less than you think. A home gym can not only be built on a budget, but it can also be an extremely smart financial decision. Read more