Transparent Labs BULK Pre-Workout Review — A Pre-Workout for Muscle Gain?

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Transparent Labs is a Utah-based supplement company with a big dedication to, well, transparency. None of their products have proprietary blends, meaning you know the exact quantity of each and every ingredient in a serving. Plus not only do they do third party testing, they actually provide certificates of analysis and composition on their site.

They have two pre-workouts, “Lean” and “Bulk,” with Bulk being focused on muscle gain. It claims to do that through increasing testosterone.

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Transparent Labs BULK
Transparent Labs BULK

Like many Transparent Labs products, it's an extraordinarily well dosed pre workout for endurance, power, and focus. Use code BARBEND10 to save 10%.


Transparent Labs BULK Ingredients

The ingredients list starts with what they call a Testosterone Support Complex of Vitamin D3 (3,000 international units, or 750 percent of the RDI), zinc (200 percent of the RDI), and boron (5 milligrams, no RDI established).

There’s also a 180-milligram dose of caffeine, about as much as you’ll find in a small Starbucks coffee.

The rest of the ingredients are:

Citrulline malate (6 grams)
Beta alanine (4 grams)
Branched chain amino acids (4 grams)
Betaine (2.5 grams)
Taurine (1.3 grams)
Tyrosine (600mg)
Choline bitartrate (500mg)
Theanine (360mg)
Mucuna pruriens, a.k.a. velvet bean extract (70mg)
L-norvaline (60mg)
Synephrine HCl, also called bitter orange extract (50mg)
Hordenine (25mg)
Bioperine®, or black pepper extract (5mg)

Note there are no artificial ingredients or flavorings, just some stevia and natural flavor, plus some anti-caking agents.

Transparent Labs BULK Pre Workout Ingredients
Transparent Labs BULK Pre Workout Ingredients

Transparent Labs Bulk Benefits and Effectiveness

That’s a lot of ingredients. What do they all do?

It’s helpful to break them down by effect. Unless otherwise noted, the doses here are pretty much in line with what’s suggested by studies.

Focus: The theanine, taurine, and tyrosine have links to focus, with theanine and taurine often used alongside caffeine because they may help reduce its attendant jitteriness. Taurine may also improve recovery by helping to draw more water and minerals into cells.

Endurance: The beta-alanine has the strongest link with endurance and while Transparent Labs’ “Lean” pre-workout has a pretty standard 1.5 grams, there’s an unusually large 4-gram dose in Bulk. Beta alanine tends to cause a harmless “tingly” sensation on the skin and four grams of it may be a bit much if you’re not a fan of that sensation.

The citrulline, norvaline, and branched chain amino acids may also have a positive effect on endurance.

Transparent Labs BULK Pre Workout Review
Transparent Labs BULK Pre Workout Review

Power: Several studies that were conducted with powerlifting movements have found that betaine can potentially improve power output. There’s also some evidence that citrulline can increase power — those studies were done on cyclists and tennis players — and the choline bitartrate could also help in that it appears to increase anaerobic capacity.

Digestion: The black pepper extract appears to help food absorb more effectively, which is why it’s sometimes included in medications.

Adrenaline: The velvet bean and the hordenine could have adrenaline-like effects, but the evidence is pretty shaky.

Testosterone: The main event. What about the testosterone?

While this isn’t as strong as steroids, there actually is some interesting evidence. Vitamin D and zinc are both strongly linked with optimal testosterone levels. One study found that over a year of taking about 3,000 IU per day of Vitamin D (the amount found in a serving of Bulk), subjects increased their testosterone levels by 20 percent. Adequate zinc intake also has a link with testosterone, but it’s important to note that neither of these nutrients will increase your T to superhuman levels. Deficiencies in these nutrients may result in a deficiency in T, getting adequate amounts of these nutrients may help bring you to baseline.

Studies are much more limited on boron, but it does appears to increase the production of testosterone and free testosterone in both men and women.

Transparent Labs Bulk Price

It’s $49 for 30 servings, which is $1.63 per scoop. That’s pretty expensive given most pre-workouts are between 80 cents and $1 per scoop, but this product is far more potent than most pre-workouts on the market. The average pre-workout gives about half as much citrulline and betaine and beta alanine, and it skips the other ingredients all together. So, I think the price is justified.

Transparent Labs Bulk Taste

I picked up the Strawberry Lemonade flavor, which I think tasted pretty great, if very sour. I’m always a little wary of naturally-sweetened pre-workouts, but lemon-flavored ones are usually pretty tasty. Strawberry Lemonade was a lot more lemon than strawberry, but if you mix one scoop with a good two cups of water it goes down very well.

The Takeaway

It’s hard to find fault with this pre-workout. It’s extraordinarily well dosed for endurance, power, and focus; it’s got black pepper extract to help everything absorb; it’s reasonably priced; and the zinc and Vitamin D make it pretty nutritious and possibly good for your testosterone.

For a muscle building pre-workout I was expecting to find other ingredients like epicatechin or l-carnitinel-tartrate, but most guys don’t get enough Vitamin D and it has a more significant and well-researched effect on testosterone than many other “muscle building” supplements have on muscle.

It’s pretty sour, there’s not a ton of evidence for the adrenaline-like effects, it’s not the highest-caffeine pre-workout around, and it might be uncomfortably high in beta alanine, but that doesn’t mean it isn’t worth a buy. I liked it.

[Use code BARBEND10 at checkout to get 10% off your order from Transparent Labs.]

Transparent Labs Bulk

Per Serving: $1.63










  • Well-dosed ingredients
  • No artificial ingredients
  • 3rd party tested


  • Expensive
  • Very sour
  • May be too high in beta alanine


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Nick is a content producer and journalist with over seven years’ experience reporting on four continents. His first articles about health were on a cholera outbreak in rural Kenya while he was reporting for a French humanitarian organization. His next writing job was covering the nightlife scene in Shanghai. He’s written on a lot of things.After Shanghai, he went on to produce a radio documentary about bodybuilding in Australia before finishing his Master’s degrees in Journalism and International Relations and heading to New York City. Here, he’s been writing on health full time for more than five years for outlets like BarBend, Men's Health, VICE, and Popular Science.No fan of writing in the third person, Nick’s passion for health stems from an interest in self improvement: How do we reach our potential?Questions like these took him through a lot of different areas of health and fitness like gymnastics, vegetarianism, kettlebell training, fasting, CrossFit, Paleo, and so on, until he realized (or decided) that strength training fit best with the ideas of continuous, measurable self improvement.At BarBend his writing focuses a little more on nutrition and long-form content with a heaping dose of strength training. His underlying belief is in the middle path: you don’t have to count every calorie and complete every workout in order to benefit from a healthy lifestyle and a stronger body. Plus, big traps are cool.