PreSeries Lean Pre Workout Review: Is 16+ Ingredients Enough For Fat Loss? [Updated 2024]

by Nader Qudimat
Updated December 21, 2023
Pre Workout
Serving Size
Widely available
Complete profile for weight loss
Fully disclosed label
Increases energy and performance
Optimizes thyroid function for weight loss
Includes essential minerals
Can cause nervousness

Bottom Line

In the small market of thermogenic pre-workouts, PreSeries Lean may just come out as one of the top choices.

It's designed to elevate thermogenesis while preventing muscle loss, and it's made for both men and women.

PreSeries Lean will keep energy and mood elevated even under caloric deficits.

The energy won't be as strong as something with exotic stimulants but in this case, it's a great choice as something that could be used nearly every day. 

Use discount code FITFREK.

Transparent Labs is well known for producing fully disclosed label supplements.

Lean is one of their main pre-workouts.

There are 3 different pre-workouts from TLabs and they are similar in profiles but different in purposes.

First comes Bulk, designed to support and optimize testosterone levels, muscle growth, and gains.

Then Stim-Free, uses the same formula as Bulk but without the caffeine.

Finally, Lean is the fat loss powder that ignites fat burning by using a special thyroid support blend.

All 3 of these pre-workouts cater to serious athletes and bodybuilders who want to get the most out of their physiques with the safest kind of formulas.

What Is PreSeries Lean

This is one of the pre-workouts that is made for weight loss.

What makes Lean special is that it uses mostly full clinical dosages of performance-enhancing ingredients along with proven thermogenic ingredients.

This means that Lean has been a top seller as a thermogenic pre-workout in the past few years.

There aren’t that many pre-workouts that have been using the same formula without major changes for a few years straight like Lean does.

Anyone who trains runs, or plays sports will enjoy using Lean.

While Lean is formulated for fat loss, it’s great as an all-around pre-workout and suits most goals. 

This is because it uses ingredients that not only optimize performance but it also uses thyroid-supporting ingredients.

It'll also help the body use fat as energy.

My Experience with Lean

Taking Lean first thing on an empty stomach in the morning is quite the experience.

The reason for this is because it's quite a stimulating experience. 

After about 20-25 minutes, the energy seems to hit its peak and it feels perfectly balanced. 

This is something that doesn't have exotic stims, so I wasn't expecting super strong energy but I also wasn't expecting to be so focused and in the zone with this pre-workout. 

It isn't overwhelming. 

It delivers great pumps, and great focus and the energy lasts a while. 

Compared to energy drinks or coffee, this is the smarter pick. 

But in terms of pre-workouts, Transparent Labs offers Bulk which in my opinion, is much better overall because it has more ingredients.

For weight loss, there isn't a supplement that will magically do this for you. 

Something like Lean will give you an extra edge. 

Under a strict calorie deficit, Lean provides energy for me and it reduces appetite but the appetite reduction isn't going to last all day and it certainly won't completely remove hunger. 

So Lean definitely helps in this regard, by providing an edge for weight loss. 

But being a legal thermogenic pre-workout that is sold from supplement stores, it can only do so much. 

It does also help with cognitive function as I noticed my mind was just so clear and I had a lot of mental energy. 

And this can be a downside when you're dieting without something like Lean as you'll experience more mental fogginess while under a calorie deficit.

Lean Ingredients

You can see Transparent Labs means business.

The list is huge and the dosages are equally great.

Some notable differences between this and Bulk are that this has less beta-alanine and more vitamins to support blood sugar and thermogenesis. 

The lower beta-alanine content might make Lean more appealing over Bulk as it’ll cause fewer tingles.

And it doesn’t have creatine or taurine, which will lead to that “dry” look that people try to achieve when shredding.

Lean makes a great pre-workout even if you’re in the bulking process.

Between this pre-workout and the others, the differences are huge, from the fully disclosed ingredient label to the natural flavoring.

It even has the basics and full days' worth of iodine, zinc, chromium, selenium, and copper.

These minerals are important for a healthy and functioning body, it makes it even more important to have if you’re on a strict diet that might strip away these nutrients.

Lean Weight Loss Support

Lean wouldn’t be a weight loss pre-workout without these “cutting” ingredients. 

Cutting is slang for fat loss in bodybuilding.

First, we’ll cover the weight loss ingredients then we’ll jump to the other ingredients.

Iodine Chelate (225mg)

For healthy and functioning thyroids, Iodine can help achieve that.

Poorly functioning thyroid will lead to weight gain, body composition, and poor resting metabolism.

Iodine will help increase thyroid function and will prevent those negative things from happening.

If you have slow thyroid function then iodine deficiency is almost always the case. 

With a proper intake of iodine, your thyroid can function properly but unfortunately, more and more people are likely to not be getting enough of iodine. [1]

If you get enough iodine then it can help with two important hormones, thyroxine (T4) and triiodothyronine (T3). [2]

Having proper T3 levels is important for heart, brain, and digestive tract health. [3]

How much you burn while resting is also determined by T3. [3]

So this means if you don't have enough T3, then your metabolism will slow down and you'll build an issue where you just keep gaining weight. [4]

You'll also be at risk for several health complications like hyperhomocysteinemia, a condition where homocysteine is built up in your blood, causing damage to your vascular tissues. [5]

Zinc AAC (30mg)

All athletes from any background will require zinc, even more than regular people because with high-intensity exercise, comes decreased zinc levels.

It’s needed for proper and optimized immune system support decreases unhealthy food cravings,  and helps optimize testosterone levels.

A 2012 meta-review found subjects with diabetes had better blood sugar regulation by supplementing with zinc. [6]

Zinc can also help reduce total cholesterol. [7]

Copper AAC (1mg)

Copper helps enhance energy and is needed to optimize metabolism and thyroid function.

Copper can also enhance the absorption of iodine.

It plays an important role in hemoglobin production, a protein that transports oxygen with red blood cells. [8]

Chromium Picolinate (200mcg)

Chromium picolinate is an important ingredient to have in a weight loss supplement but it’s highly underrated.

It’s been shown to regulate blood sugar and suppresses appetite so you’ll be less likely to have junk food cravings.

The way it does this is by strengthening and improving insulin production. 

But unfortunately, insulin resistance is becoming a common problem among Americans. [9]

Chromium is used in insulin production and signaling, telling the body to use the carbs that you obtain from your diet. [10, 11, 12]

Supplementing with chromium has been shown to improve blood glucose regulation and the form that's been shown the most effective and bioavailable is chromium picolinate. [13, 14]

It's also been shown to improve blood sugar and insulin response in subjects. [15]

Another benefit that chromium has is that it can reduce the cravings you have for carbohydrate-rich foods and you'll be less likely to crave fatty foods. [16, 17]

Supplementing with chromium means you'll have a healthier appetite, eat less junk food and you'll have improved serotonin levels as a side benefit. [18]

You can see Transparent Labs has really thought out and planned Lean to be a very effective fat-burning pre-workout without requiring heavy stimulants. 

Selenium (L-Selenomethionine, 50mcg)

We've already gone over how iodine is important for thyroid health and weight loss. 

Selenium is just as important as iodine for weight loss. 

The thyroid gland contains the highest concentration of selenium out of any other organ or gland in the body. [19]

The deiodinase enzymes which need the selenium to function, are going to turn T4 into T3. [19]

Being deficient in selenium means weight loss will be nearly impossible as it'll ruin your thyroid function. 

Selenium is also an antioxidant compound, which can help protect the thyroid glands from oxidative stress. [19]

Citrulline Malate (6g)

Citrulline malate helps with workout performance by decreasing and eliminating lactic acid content in your muscles.

This works similarly to beta-alanine and it’s comparable to agmatine when it comes to pumps.

Citrulline helps elevate nitric oxide levels, meaning more muscle hardness and all-day pumps from this ingredient alone.

Citrulline is an amino acid that can increase vasorelaxation, which is when blood flow is increased throughout the body.

Research shows a single 6-gram dose of citrulline can enhance exercise performance and oxygen uptake. [20]

There are so many benefits to having increased nitric oxide production, including improved performance in the gym and better recovery. [21, 22, 23]

A meta-analysis performed in 2020 used 13 studies to find that citrulline can decrease perceived exertion during exercise and reduce soreness post-workout. [24]

Lean has citrulline to help with workout performance, which is going to be key when you're dieting as you likely won't be getting enough support from your diet if you're trying to lose weight. 

Beta Alanine (2g)

Known for the tingles, beta-alanine decreases the lactic acid build up that occurs from high exertion. 

Doing this, it’ll help delay fatigue and allow you to push for more reps and weight while increasing strength and muscle gains. 

It does this by increasing the production of carnosine. [28]

Research has found beta-alanine can increase exercise capacity by helping increase the total volume performed during a workout. [29, 30]

Like creatine, beta-alanine takes time to saturate and work. 

This dose is a bit low but you should have beta-alanine in bulk anyway to make the most out of it.

BetaPure Betaine Anhydrous (1.5g)

For power and strength, betaine is an excellent choice.

It works like creatine and it also increases muscle size while stimulating muscle growth. [31]

Betaine is found in beets, and it’s been shown to optimize HGH while decreasing cortisol, leaving you in an optimal state for weight loss and muscle gains. [32, 33]

Betaine will help increase performance by decreasing fatigue, allowing you to push for more reps before feeling fatigued.

It also helps with hydration. [34]

Acetyl-L-Carnitine (1g) 

Alcar, or the long name, Acety L-Carnitine is a super bioavailable form of carnitine that can enter the blood-brain barrier. [35, 36, 37]

Research has proven time and time again that this is a great nootropic ingredient with a range of benefits for mental health. 

One of the reasons why it's so effective is because it's bonded with acetyl, and has been shown to help with acetylcholine, a neurotransmitter that's heavily involved in important mental functions. 

While the dose here is a bit low, it's just enough to see benefits. 

More effective doses of acetyl l-carnitine is typically around 1.5g as it would have more carnitine. 

Choline Bitartrate (500mg)

Choline is a nootropic that helps enhance focus and it works well when it’s combined with betaine. 

On a strict diet, you may have a reduced attention span, but with choline bitartrate, you have better mental functions.

Choline can be naturally acquired from diet but if you're cutting then you may not be getting enough. 

It helps with acetylcholine production which plays an important role in not only mood and memory but also muscle control. [40]

When you don't have enough choline, it'll put you at risk for several health issues and complications. [41]

Using enough choline will ensure that this doesn't happen and that your brain and central nervous system will be functioning at its best. 

Transparent Labs has a solo nootropic formula that you can also check out here.

Theanine (180mg)

When you need prolonged focus and energy then you’d be right to choose theanine. 

Theanine is an amino acid that’s found in green tea, and it produces a relaxing effect that puts you in the zone while not having any sedative effects. 

So you’re at the top of your mental functions without feeling jittery or sleepy. 

At 180mg, it’s a moderate dose and it’ll surely lead to some long-lasting focus while reducing the typical pre-workout crash. 

The upside is that theanine has calming effects that reduce anxiety. [41, 42, 43, 44]

Caffeine (180mg)

A sort of low but effective dose of 180mg caffeine will produce some nice energy without any jitters, especially since it’s combined with the theanine. 

There are 2 different forms of caffeine in Lean, totaling around 230mg.

Caffeine will help reduce fatigue and increase energy by inhibiting adenosine, an enzyme that builds up in your mind while you're awake. [45]

Theobromine (50mg)

Very similar to regular caffeine, theobromine is a methylxanthine alkaloid that naturally occurs in coffee, tea, chocolate, and more. [50]

It helps with energy by inhibiting phosphodiesterase, an enzyme that breaks down cyclic adenosine monophosphate (cAMP), a hormone that instructs cells to use glucose and fatty acids for energy. [51]

It can reduce fatigue by functioning as an antagonist for adenosine, something that builds up in your brain when you're awake. [52]

The reason why theobromine is considered to be a thermogenic compound is that it can convert white adipose tissue into brown adipose tissue. [53]

By doing this, it'll instruct cells to use fatty acids for energy as brown adipose tissue is readily used for energy. 

This ingredient alone helps drive PreSeries Lean to being a strong thermogenic pre-workout. 

BioPerine (5mg)

With so many ingredients, there’s bound to be some small absorption issues. 

There’s so much to digest. 

Luckily BioPerine helps enhance absorption of all the ingredients here.

Huperzine (100mcg)

Since there's already choline in here, Huperzine will be nice in this formula. 

It'll help prevent the breakdown of acetylcholine. 

This means you'll have longer lasting focus throughout the day and better concentration. 

Flavors Available

The flavor selection increases every now and then, even though Transparent Labs uses all natural ingredients, for all their supplements.

Check out this list:


In our opinion, Lean is worth the cost. 

This is something that has not only thermogenic compounds but also immune boosting ingredients as well as ergogenic aids to help increase exercise performance. 

Comparable pre-workouts are slightly more expensive, especially considering that the cost of Lean goes down when you buy multiple bottles.

But again Lean won't do the fat burning for you, you'll still need to be a caloric deficit.

Fat-burning pre-workouts or supplements can only do so much while being legal and safe. 

Fat Burning Pre Workout
PreSeries LEAN Pre-Workout by Transparent Labs

Lean is designed to support weight loss from multiple angles, including improving insulin sensitivity and glucose metabolism.

Ingredients: 6g Citrulline Malate, 2g Beta Alanine, 1.5g Betaine Anhydrous, 1g Acetyl L-Carnitine HCl, 500mg Choline Bitartrate, 180mg Theanine, 5mg BioPerine, 100mcg Huperzine
Stimulants: 180mg Organic Caffeine, 50mg Theobromine, 40mg Infinergy Caffeine
  • Increases thermogenesis
  • Improves glucose metabolism
  • Increases fat metabolism for energy
Discount code: FITFREK
FitFrek earns a commission if you click this link and make a purchase, at no additional cost to you.

Lean Your Way Out

With so few weight loss pre workouts out there, Lean easily makes it at the top recommendation for an future-proof weight loss pre workout.

As we see supplements with ephedra and DMAA slowly disappearing from supplements, Lean paves the way with a future-proof formula that is unlikely to be formulated anytime soon.

It uses a fully transparent formula that attacks weight loss from several angles.

Read up more about Transparent Labs and their supplements here.

by Nader Qudimat

Forged by iron and cold steel, I'm Nader, a mid-30s natural bodybuilder. Once a 100lb skinny guy, I've transformed into a 200lb muscular athlete with over 15 years of lifting experience. Today, I leverage my transformation and extensive experience to guide countless individuals on their fitness journeys.

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

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