After taking Transparent Labs LEAN for two weeks and combing through the ingredients, I can say that this product doesn’t live up to its marketing hype of being an exceptional pre-workout for cutting.

That said, I love Transparent Labs BULK and recommend spending your money on that product, whether you’re cutting, bulking, or maintaining. Transparent Labs is also one of the few supplement companies that takes purity, third-party testing, and, unsurprisingly, the transparency of its ingredients seriously. 

I actually love the company; I just don’t love its LEAN product line.

Transparent Labs LEAN Alternative: Transparent Labs BULK

At the same price as LEAN, you’ll get more L-citrulline and betaine anhydrous, plus an extra 20 mg of caffeine. However, BULK has 4,000 mg of beta-alanine, which isn’t ideal if you don’t like the tingles.

You can read my full review of Transparent Labs BULK here. But the bottom line is that BULK has higher doses of the key ingredients that might improve your training. 

But there are some cases where Transparent Labs LEAN might be a better option than BULK. Read on to find out who might be better off, at least initially, with LEAN.

You can see all my pre-workout reviews here.

My skepticism stems from why this is marketed for “cutting.” 

I mean, yes, LEAN has five calories less than BULK, but I can tell you that those five calories make f*ck all difference to your results. And yes, LEAN has L-carnitine for fat burning, but come on…

In any case, the logic behind BULK and LEAN doesn’t make sense. I think it’s all a marketing ploy. 

Best For:

When you’re new to pre-workouts and just want to try something.

The lower doses of caffeine and L-citrulline might be enough to get you going, especially if you’re sensitive to caffeine.

When you can’t stand the tingles.

Transparent Labs LEAN has only 2,000 mg of beta-alanine. And while it’s a far cry from the minimum effective dose, it’s good news if you don’t like the tingles that come with a full hit of beta-alanine.

Not For:

Experienced lifters.

Transparent Labs LEAN doesn’t offer enough of anything to maximize the benefits of a pre-workout. Its suboptimal doses of beta-alanine and L-citrulline make it underwhelming.

If you’re cutting or simply trying to lose fat.

I’m not convinced LEAN will boost fat loss. Plus, when you’re losing weight, you typically have fewer carbs, and the pump is harder to come by. So you should want MORE, not less, L-citrulline. 

For those reasons, Transparent Labs BULK makes more sense when cutting. And since it costs the same as LEAN, going with BULK is an absolute no-brainer.

If you want a pre-workout with minimal ingredients.

There’s just way too much pointless crap in here.

Transparent Labs LEAN Ingredients

According to Transparent Labs, “LEAN was developed for a single purpose: to be the most exceptional cutting pre-workout supplement, ever.” Well, they should’ve tried harder and focused on delivering enough of the key ingredients to a good pre-workout.

You could also easily cut out six to seven ingredients, which would make this product way more appealing. 

On a more positive note, I actually reached out to Transparent Labs to clarify the trademarked ingredients it’s using. I received a swift response with thorough explanations of the ingredients, including the proprietary ones.

Citrulline Malate 2:1

6,000 mg

L-citrulline malate is two ingredients baked together: L-citrulline and malic acid. At a 2:1 ratio, Transparent Labs LEAN packs 4,000 mg of L-citrulline and 2,000 mg of malic acid. 

Malic acid may help your body absorb L-citrulline. But L-citrulline is the star here. When dosed right, it can give you a better pump in your training. It won’t make you stronger, but it can help you squeeze out a couple of reps.^[1] 

The minimum effective dose of L-citrulline is 4,000 mg, and Transparent Labs LEAN covers that. But it’s likely not enough for experienced lifters. 

Beta-Alanine

2,000 mg

Beta-alanine will only improve your training if you reach the saturation point of 179,000 mg over continuous daily use.

It’s also the ingredient that causes that tingly sensation.

Without reaching the saturation point, you’re left with just the tingles, which are nothing more than a sign of an acute high dose of beta-alanine. Those tingles aren’t a sign that beta-alanine is about to turn you into a turbo-human. 

That being said, those tingles can make you think that the pre-workout is taking effect, which can help you train harder. Yes, it’s a placebo. But if it works, why not?

If you want to reach the saturation point and reap those potential performance benefits of beta-alanine, the minimum effective daily dose is 3,200 mg.^[2] Transparent Labs LEAN gets you nowhere near that.

But again, BULK does. Not that it makes a difference unless you take pre-workout every day. Or at least supplement beta-alanine on its own on the off days.

Betaine Anhydrous (BetaPure™)

1,500 mg

BetaPure is a patented version of Betaine Anhydrous from non-GMO sugar beets. It’s a popular ingredient in pre-workouts for improving intracellular hydration, which can lead to a better pump.^[3] Although the science of this is sketchy af.

Unlike what the supplement makers want you to believe, the science on betaine anhydrous for performance improvement is, as one of my German friends would say, scheiße.

The minimum effective dose of betaine anhydrous is 2,500 mg.^[3] Transparent Labs LEAN doesn’t meet that, and therefore, you won’t get any potential benefit from this dosage.

Acetyl L-Carnitine HCI

1,000 mg

Acetyl-L-carnitine is a form of L-carnitine, which plays an important role in fat metabolism. L-carnitine can help your body use more fat for energy after training, but only if you don’t mix it with sugar.^[4] 

L-carnitine doesn’t make your body use more energy overall; it just helps it choose fat as the energy source. Whether that effect is significant enough to get excited about is another story. 

Fat loss is all about energy balance, so if you’re trying to cut, focus more on calories in vs. calories out instead of chasing some miracle fat-burning supplement.

Anyway, the 1,000 mg of L-carnitine does meet the minimum effective dose.

Choline Bitartrate

500 mg

Choline supplementation might have limited effects on memory and physical performance in healthy young adults and trained athletes, but supplementation does not consistently improve performance.^[5]

L-Theanine

180 mg

L-theanine is a naturally occurring amino acid, and supplementing it can improve cognitive function. It can also reduce the elevated blood pressure and sleep issues that often come with caffeine.

The current evidence suggests that combining caffeine and L-theanine at a 2:1 or 1:1 ratio might improve focus and attention during super-demanding mental tasks.

At 180 mg of L-theanine, Transparent Labs LEAN hits the minimum effective dose.^[6]

PurCaf® Organic Caffeine

180 mg

The recommended daily caffeine limit is 400 mg (roughly four cups of brewed coffee). The 180 mg in Transparent Labs LEAN is likely enough to improve focus and energy unless you’re an absolute caffeine maniac.^[7]

As a side note, PurCaf is 95% caffeine. The other 5% is minor green coffee bean constituents (such as polyphenols), moisture (water), and macronutrients (e.g., carbs, fiber, and protein from coffee beans).

Theobromine

50 mg

Theobromine is caffeine’s calmer cousin. Where caffeine affects the nervous system, theobromine acts by improving blood flow and making the heart pump more efficiently.^[8] 

At 50 mg, Transparent Labs LEAN hits the minimum effective dose of theobromine and can improve focus and energy and help offset caffeine crashes.^[9] But I wouldn’t hang my hat on those claims.

Zinc (as Zinc Amino Acid Chelate)

15 mg

Whether zinc will do anything for you depends on your zinc levels.^[10] Supplementing a random dose of zinc as part of your pre-workout is about as fruitful as talking to your dog about the geopolitical stability of sub-Saharan Africa.

Bioperine® (Black Pepper Extract)

5 mg

Black pepper is a source of piperine, which doesn’t do a lot on its own but can enhance the absorption of other supplements. However, the data on piperine and the supplements included in Transparent Labs LEAN is weak.^[11]

Still, this is essentially just black pepper, so why not chuck it in just in case it might do something?

Copper

1 mg

Copper is essential for energy metabolism. It also contributes to connective tissue health, antioxidant defense, immune function, and the nervous system. 

But most people don’t need to supplement copper to get those benefits. That 1 mg won’t hurt you, but it won’t help you either.^[12] I think it’s in here (like so many other ingredients) to make the product look more appealing for people who don’t know any better. The more, the better kind of thing. But they’re not going to fool you and me!

Iodine

225 mg

Supplementing iodine doesn’t do much for adults since most people in the developed world get enough of it as it is.^[13] 

Having iodine in Transparent Labs LEAN is, yet again, pointless.

Chromium (Chromate®)

200 mcg

There’s no clear evidence on the benefits of supplementing chromium or why it should be in a pre-workout.^[14] As with so many other ingredients, chromium in Transparent Labs LEAN is incomprehensible.

Huperzine A

100 mcg

Huperzine A is a compound extracted from the herbs of the Lycopodiaceae family and has some cognitive health and potential neuroprotective effects for people with Alzheimer’s. 

But no science proves its effect on improving performance, not even as a cognitive enhancer. In fact, it was worse than the placebo.^[15]

Selenium

55 mcg

Selenium plays essential roles in immune function and antioxidant defense, but it has zero effect on athletic performance. That being said, supplementing selenium may prevent selenium deficiencies in athletes who train with high-intensity and high-volume training. 

By “athletes,” I don’t mean Old Jimbo from next door, who hits 12 sets of bench press every Monday. But actual athletes, who train at super strenuous, demanding training loads typical at the elite level.^[16]

My Experience Using ​​Transparent Labs LEAN Pre-Workout

As with all the pre-workouts I review, I use Transparent Labs LEAN for two weeks before all my training sessions. 

I noticed a slight difference in focus and energy from the caffeine/theanine combo. So, it wasn’t all shit.

But the marketing Transparent Labs uses for LEAN vs. BULK is rather confusing — and even misleading. Most of it’s not fully backed up by the ingredient breakdown. Plus, some key ingredients in LEAN are underdosed for experienced lifters.

Let me explain. 

Price

[image of the serving size]

Transparent Labs LEAN costs $1.66 per serving and comes down to $1.49 if you subscribe.

The shipping is $7.99. But you get free delivery with subscriptions and orders over $100.

Third-Party Tested and GMP Certified

[screenshots of third-party test results]

Transparent Labs LEAN is third-party tested for purity and potency. Hooray! Transparent Labs lists certificates of compositions provided by a third-party company for all its products. LEAN is also GMP certified, confirming that its manufacturing complies with safety and quality standards.

If you’re looking for purity testing on every batch of Transparent Labs’ products, you can access the certificate of analysis on the website.

Energy

A paltry 180 mg of caffeine doesn’t do much for me. I did notice a difference with it, but just as I’m not going to survive the day with one measly cup of coffee, I find it hard to get good training in without a higher dose of caffeine. 

Likewise, the tingles from beta-alanine were a non-event. As is the common theme with Transparent Labs LEAN, the dose is too low.

Pump

The pump was better than not taking pre-workout at all, which isn’t saying much. 

Since the pump is one of the two main reasons (the second being energy and focus) I take a pre-workout, I kind of want it to be good. That 4,000 mg of L-citrulline isn’t enough to give me a proper pump. Even if it clears the bar for a minimum effective dose.

Taste

[screenshot of flavors from the website]

Transparent Labs LEAN is available in nine flavors:

• Strawberry Lemonade
• Sour Grape
• Fruit Punch
• Cherry Splash
• Sour Peach
• Blue Raspberry
• Green Apple
• Orange
• Tropical Punch

I tried the Strawberry Lemonade first, and it was absolute garbage. The Blue Raspberry was a bit better, but only just.

Shitty flavors seem to be the norm with Transparent Labs products. I had a similar experience with BULK and many online reviews agree. But there’s a silver lining here.

Pre-workouts with higher doses of the key ingredients often have an average flavor simply because it’s harder to mask the taste of the ingredients. 

Transparent Labs doesn’t use any artificial sweeteners or colors. The older I get, the more I care about the purity of the product and less about the flavor.

Mixability

[image of the pre-workout mixed up]

Transparent Labs LEAN mixed well. There was no grittiness, clumps, or other annoying things to get in the way of the drinking experience. Although…maybe clumps and a sand-like texture would distract people from the hideodorous flavors. 

Customer Experience

The whole ordering process and delivery were outstanding. The website is easy to use, and I wasn’t bombarded with bullshit marketing emails after ordering. The delivery was quick, too. 

How I Tested ​​Transparent Labs LEAN Pre-Workout

1. Ingredients

I care mostly about two ingredients in pre-workout supplements: caffeine and L-citrulline. Then there are two that might be worth your dollars: beta-alanine and electrolytes. But those two are far from mandatory.

Once I know a pre-workout has the two ingredients I care about, I check that the dosage of both ingredients is where it should be to provide the stimulation I need. 

Besides those two, most other ingredients serve a different purpose: marketing. The fewer ingredients I see on the label, the better. 

You can read more about the ingredients I look for on my how I test ingredients page. 

2. Price per serving

I care whether a single serving will give me enough of the four ingredients above for the needed stimulus. Ultimately, I want the best bang for buck per serving. 

Often, the key ingredients are about the same in most pre-workout supplements. It’s the proprietary blends and trademarked ingredients that raise the price. Both of which rarely contribute to the quality or effectiveness of the supplement. 

Another reason why fewer ingredients are better is that it keeps the cost down.

You can read more about how price factors into my scoring system here.

3. Third-party testing and Good Manufacturing Practice certification

When a supplement company wants third-party testing and certification, it pays an outside organization to test for ingredient potency and accuracy.

Getting certified means an independent organization has reviewed the product and determined it complies with safety, quality, and performance standards.

The absence of third-party testing doesn’t immediately mean a poor product. But knowing the dishonest bullshitting going on in the supplement industry, third-party testing gives me peace of mind knowing a product is safe and has — and does — what it says on the box. 

GMP (Good Manufacturing Practice) certification means the manufacturing facilities comply with the rigorous quality standards of regulatory authorities. It covers the entire manufacturing process, including sourcing of raw materials, production processes, packaging, and labeling. 

These guidelines provide minimum requirements that a manufacturer must meet to ensure its products are consistently high in quality.

In short, third-party testing is about the product, and GMP compliance covers the manufacturing.

Read more about third-party testing and GMP compliance here.

4. Energy

Out of all the effects I look for in a pre-workout, this is the one I care about the most. I want to feel psyched and focused for my strength training. And I want to finish without getting the dreaded post-workout caffeine crash.

You can read more about how energy factors into my scoring system here.

5. Pump

The second most important thing I need from a pre-workout is the pump. The product must have enough L-citrulline (4,000 mg) to increase the blood flow into the muscles I’m working. In most cases, anything less than 6,000 mg and I’d rather spend my money elsewhere.

Read more about what I look for when scoring the pump.

6. Taste

Let’s face it: Making a good, even great-tasting pre-workout isn’t difficult. Anything less than 8/10 is only acceptable if the product is otherwise exceptional. Luckily, most pre-workouts taste good, so don’t get too hung up on this number unless it’s anything less than 8 out of 10, as it is mostly about my preference.

You can read more about how taste factors into my scoring system here.

7. Mixability

I need a pre-workout that’s easy to mix in a shaker. That means no powder clumps! I expect something smooth and grit-free that doesn’t get stuck on the side of the shaker. Most pre-workouts add silicon dioxide and calcium silicate as anti-caking agents, so look for that if you’re as annoyed by clumps as I am.

Read more about how mixability factors into my scoring system.

8. Customer experience

In this testing stage, I find and navigate the website, complete the ordering process, and accept delivery, evaluating each company every step of the way. I also review customer service in cases where I have problems with the order. I have high expectations for customer service and will harshly judge brands with missing links in their customer experience.

You can learn more about how customer service factors into my scoring system here.

Conclusion

Transparent Labs LEAN doesn’t deliver on its promise of being an exceptional pre-workout for cutting. It’s simply too low on the key ingredients to deliver the pump and energy you want from a pre-workout, especially if you’re cutting, when the pump is harder to get in the first place.

And whether L-carnitine improves fat burning is a moot point. If it does, it might make a 0.0001% difference to your results. You’re better off focusing on diet, training, and recovery.

Now, it’s not all bad. Transparent Labs LEAN could work if you’re new to pre-workouts and looking for a moderate energy boost with some potential pump.

But for more advanced users like me, this isn’t the product you want or need. Get Transparent Labs BULK instead.

FAQs

References

1. Aguiar, A. F., & Casonatto, J. (2022). Effects of citrulline malate supplementation on muscle strength in resistance-trained adults: A systematic review and meta-analysis of randomized controlled trials. Journal of Dietary Supplements, 19(6), 772–790. https://doi.org/10.1080/19390211.2021.1939473

2. Trexler, E. T., Smith-Ryan, A. E., Stout, J. R., Hoffman, J. R., Wilborn, C. D., Sale, C., Kreider, R. B., Jäger, R., Earnest, C. P., Bannock, L., Campbell, B., Kalman, D., Ziegenfuss, T. N., & Antonio, J. (2015). International society of sports nutrition position stand: Beta-alanine. Journal of the International Society of Sports Nutrition, 12, 30. https://doi.org/10.1186/s12970-015-0090-y

3. ​Ismaeel A. (2017). Effects of betaine supplementation on muscle strength and power: A systematic review. Journal of Strength and Conditioning Research, 31(8), 2338–2346. https://doi.org/10.1519/JSC.0000000000001959

4. Odo, S., Tanabe, K., Yohda, M., & Yamauchi, M. (2020). Liver-oriented acute metabolic effects of a low dose of l-carnitine under fat-mobilizing conditions: Pilot human clinical trial. Journal of Nutritional Science and Vitaminology, 66(2), 136–149. https://doi.org/10.3177/jnsv.66.136

5. Examine. Choline. https://examine.com/supplements/choline/

6. Examine. Theanine. https://examine.com/supplements/theanine/

7. Guest, N.S., VanDusseldorp, T. A., Nelson, M. T., Grgic J., Schoenfeld, B. J., Jenkins N. D. M., Arent S. M., Antonio, J., Stout, J. R., Trexler, E. T., Smith-Ryan, A. E., Goldstein, E. R., Kalman, D. S., & Campbell, B. I. (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18(1). https://doi.org/10.1186/s12970-020-00383-4

8. Mitchell, E. S., Slettenaar, M., Meer, N. vd., Transler, C., Jans, L., Quadt, F., Berry, M. (2011). Differential contributions of theobromine and caffeine on mood, psychomotor performance and blood pressure. Physiology and Behavior, 104(5), 816–822. https://doi.org/10.1016/j.physbeh.2011.07.027

9. Gao, L., Ge, W., Peng, C., Guo, J., Chen, N., & He, L. (2022). Association between dietary theobromine and cognitive function in a representative American population: A cross-sectional study. The Journal of Prevention of Alzheimer’s Disease, 9(3), 449–457. https://doi.org/10.14283/jpad.2022.39

10. Examine. Zinc. https://examine.com/supplements/zinc/

11. Examine. Zinc. https://examine.com/supplements/black-pepper

12. Examine. Copper. https://examine.com/supplements/copper/

13. Examine. Iodine. https://examine.com/supplements/iodine/

14. Examine. Chromium. https://examine.com/supplements/chromium/

15. Jędrejko, K., Catlin, O., Stewart, T., Anderson, A., Muszyńska, B., & Catlin, D. (2023). Unauthorized ingredients in “nootropic” dietary supplements: A review of the history, pharmacology, prevalence, international regulations, and potential as doping agents. Drug Testing and Analysis. https://doi.org/10.1002/dta.3529

16. Kieliszek, M., & Lipinski, B. (2020). Selenium supplementation in the prevention of coronavirus infections (COVID-19). Medical Hypotheses, 143, 109878–109878. https://doi.org/10.1016/j.mehy.2020.109878