A stimulant pre-workout runs on caffeine; a pump pre-workout runs on blood-flow ingredients like citrulline, with no caffeine. Caffeine has the bigger body of proof (the International Society of Sports Nutrition says 3 to 6 mg per kg consistently improves performance), while a 2021 meta-analysis of 8 studies found 6 to 8 g of citrulline malate added about 3 reps in total (6.4%) across sets taken to failure. Neither builds muscle on its own; the sets do that.
Around 1,800 searches a month go into “pump pre workout” on Google, and the question that lands on this page most is blunter: does pre-workout give you a better pump?
The Short Version
- Caffeine works, at a dose: 3 to 6 mg per kg of body weight improves muscular endurance, strength and sprint performance in many but not all studies (ISSN position stand, 2021).
- Pump ingredients help a little: 6 to 8 g of citrulline malate, 40 to 60 minutes before training, added about 3 reps in total (6.4%) across an exercise’s sets to failure, a small effect (meta-analysis of 8 studies, 137 people, 2021).
- Caffeine is the feeling: in a trial of 24 trained adults, a caffeinated and a caffeine-free pre-workout both raised peak isometric squat force over placebo; only the caffeinated one raised energy ratings (Stratton and colleagues, 2022).
- Ninja Swole holds 7000 mg of L-citrulline malate 2:1 a scoop, inside the 6 to 8 g range the citrulline studies used, and its label lists no caffeine.
What Is the Difference Between a Pump and a Stimulant Pre-Workout?
The difference is the engine: a stimulant pre-workout is built around caffeine, and a pump pre-workout is built around nitric oxide precursors such as citrulline and arginine, aimed at blood flow to the working muscle. One wakes you up; the other is meant to send more blood where the sets are.
Think of it as a car on Ocean Drive. The stimulant is the engine note you hear the moment you turn the key. The pump is the paint job: it looks great under the neon and it is gone by morning. What actually moves the car is the training.
| Stimulant pre-workout | Pump (stim-free) pre-workout | |
|---|---|---|
| Built for | Energy, focus, alertness | Blood flow and the pump, with no buzz |
| Best evidence | 3 to 6 mg of caffeine per kg improves endurance and strength in many studies (ISSN, 2021) | 6 to 8 g of citrulline malate: about 6% more total reps to failure, a small effect (meta-analysis, 2021) |
| Usual timing | Most often 60 minutes before training | 40 to 60 minutes before, as in the citrulline studies |
| Late sessions | Caffeine can cost you sleep | No caffeine on the label, so the clock matters less |
| Skip it if | You are caffeine sensitive, under 18, pregnant or nursing | You want a kick you can feel |
| Ninja’s version | Ninja Up, Ninja Up NoYo, Ninja Unleashed | Ninja Swole |
One honest wrinkle: a stimulant formula can carry pump ingredients too. Ninja Up holds 6000 mg of L-citrulline malate next to its caffeine, so “pre-workout vs pump” is often “pump ingredients with caffeine” against “pump ingredients without it”. What each ingredient does, and at what dose: the pre-workout ingredients that actually work.
Does Pre-Workout Give You a Better Pump?
Not reliably, and that includes the pump formulas. Citrulline is the ingredient built for blood flow, yet the two trials that measured the pump directly found no extra effect. In a 2018 study, 12 trained men took 8 g of citrulline malate or a placebo before five sets of bench press. Their triceps swelled after the sets either way; the supplement did not add to it.
A 2023 study gave 18 trained men and women 8 g of L-citrulline or a placebo an hour before testing. It found no change in muscle oxygenation, reps or strength, and no change in how pumped people said they felt.
So where does the pump in the ads come from? The training. In 2018 the swelling came from five sets of up to 15 reps with 2 minutes of rest, supplement or not. That is the paint job: the sets put it on. A stimulant pre-workout is not designed for the pump at all; it is designed to get you through those sets with more drive.
Do Pump Pre-Workouts Actually Work?
Yes, for performance, by a small margin. In the 2021 meta-analysis of 8 double-blind studies, citrulline malate raised total reps to failure by 6.4% on average; split by upper and lower body, neither result was significant on its own. Small, not magic.
The most useful study for this exact question came from Texas Tech in 2022. Twenty-four resistance-trained men and women took a caffeinated pre-workout, an otherwise identical caffeine-free version, or a placebo, in turn.
- What both bought: more peak force on an isometric squat than placebo, by a similar margin.
- What neither bought: better bench press, leg press or isokinetic squat numbers in the lab.
- What only the caffeine bought: higher energy ratings.
Arginine silicate, sold as Nitrosigine, has a smaller record. In a 2015 trial, 10 healthy men took 1500 mg a day: blood arginine rose within 30 minutes of the first dose, and after 14 days a saliva marker of nitric oxide had risen in six of the ten. It measured blood and saliva, not the pump or the bar: a clue, not a result.
Is Pump or Stim Better for Muscle Gain?
Neither builds muscle; the training does, and the better pre-workout is the one that gets more good sets out of you. The 2026 American College of Sports Medicine position stand, built on 137 systematic reviews and more than 30,000 people, found growth was enhanced by higher volume (10 or more sets a week) and eccentric overload, while training to failure and time under tension did not consistently change the outcome.
If caffeine gets you through the door at 6 AM and through the last two sets, it is helping your gains. If caffeine at 7 PM costs you the night, it is not: sleep trouble is a caffeine side effect the ISSN names, along with feeling on edge. If a stimulant scoop leaves you wired, read why pre-workout makes you jittery and how to stop it.
Pump or Stim: Which One Should You Pick?
Pick by your schedule and your caffeine tolerance, not by the label art.
- Pick a stimulant pre-workout if: you train early or after a long day and need the drive, you handle caffeine well, and your session ends many hours before bed.
- Pick a pump pre-workout if: you train in the evening, you are caffeine sensitive, you already had your coffee quota, or you train twice a day and the first scoop was the caffeinated one.
Still torn between Ninja’s four tubs? We lined them up by label: which pre-workout is right for you.
Can You Take a Pump and a Stimulant Pre-Workout Together?
You can, but read both labels first. A full scoop of Ninja Up plus a full scoop of Ninja Swole means 13,000 mg of citrulline malate and 6400 mg of beta-alanine in one sitting, well above the 6 to 8 g of citrulline malate the studies used.
The simpler move is to rotate: the caffeinated tub for mornings and low-energy days, the pump tub for evenings and second sessions. Count every milligram of caffeine against the FDA’s 400 mg a day for most adults, coffee included.
Coach’s Corner: The Pump Session (Upper Body)
- Scoop and warm up: take a pump scoop 40 to 60 minutes before your first working set, then 5 minutes easy on the bike or rower.
- Incline dumbbell press: 3 x 10 to 12, 90 seconds rest. Elbows about 45 degrees from your sides, two counts on the way down.
- Chest-supported dumbbell row: 3 x 10 to 12, 90 seconds rest. Pull to your lower ribs and pause for one second at the top.
- Dumbbell lateral raise: 3 x 12 to 15, 60 seconds rest. Lead with the elbows and stop at shoulder height.
- Cable curl and rope pushdown superset: 2 x 12 to 15 each, 60 seconds rest after the pair. Elbows pinned to your sides, no swinging.
Healthy adults: if you have an injury, pain, a heart condition, or you are new to training, check with your doctor before you start. Stop if it hurts.
The Fuel Plan
| 80 kg lifter | 100 kg lifter | |
|---|---|---|
| Protein a day (1.4 to 2.0 g per kg, ISSN) | 112 to 160 g | 140 to 200 g |
| Protein per meal (about 0.25 g per kg, ISSN) | about 20 g | about 25 g |
| Caffeine range in the studies (3 to 6 mg per kg) | 240 to 480 mg | 300 to 600 mg |
| FDA figure for most adults, every source counted | 400 mg a day | 400 mg a day |
| A pump scoop (Ninja Swole) | 40 to 60 min before training | 40 to 60 min before training |
Where the two caffeine rows disagree, the lower number wins. Ninja Swole adds no protein: spread food protein across meals every 3 to 4 hours (ISSN). These are general numbers for healthy adults. With kidney disease, diabetes or any medical diet, ask your doctor or a registered dietitian.
Where Ninja Swole Fits
If the pump column is the one you want, check the dose first. Ninja Swole is our stim-free pre-workout (that is the name on the label and the store): 7000 mg of L-citrulline malate 2:1 a scoop, inside the 6 to 8 g the citrulline studies used, plus 1500 mg of Nitrosigine, the same daily amount as the 2015 arginine trial. The label carries no caffeine row, which means no caffeine math for a 7 PM session. If you lift after work and you are done with caffeine for the day, this is the tub.
Who it’s for: lifters who want a stim-free pump: evening training, a second session, the caffeine sensitive, or anyone already past their coffee for the day. Who it’s not for: anyone who wants a stimulant kick they can feel; that is Ninja Up’s job.
Ninja Swole: The Doses This Article Is About
Per serving, straight from the label. The full label is on the product page.
| L-Citrulline Malate 2:1 | 7000 mg |
| Nitrosigine® as Inositol-Stabilized Arginine Silicate | 1500 mg |
| VasoDrive-AP® (Hydrolysed Casein Tripeptides) | 254 mg |
| Beta Alanine | 3200 mg |
| Betaine Anhydrous | 2500mg |
| Alpha GPC (50% Alpha Glycerylphosphorylcholine) | 600 mg |
The numbers: $49.99 for 25 servings is $2.00 a scoop, or $1.70 a scoop with Subscribe and Save at 15% off. Flavours on sale: Bomb Pop, Rainbow Candy and Watermelon.
The product Ninja Swole buyers add most often is Ninja Up: a stim tub for the mornings, a pump tub for the nights.
I have tried many pre workouts on the market This is hands down my favorite. I have tried and used all three lines of Ninja pre workouts for years and ALL of them are great! Flavors are spot on and I like the Non-Stim for more of a daily use vs. high stem or regular, but rotate all of them. Easily the best supplement line on the market. . . . .
The longer I worked out the tighter my shirt got which tells me 2 things. One, the pump was as advertised and more and two, the focus and endurance was on point giving the length of my workout. 5 stars all the way
This is the best non Stim Preworkout I’ve ever had. I never ran out of a tub quicker than before. This really does give you amazing endurance!
If you take prescription medication, check with your doctor first.
Frequently Asked Questions
How much bigger does a pump make you?
A pump is temporary swelling from blood and fluid in the worked muscle, and it fades after the session. In a 2018 trial, triceps thickness rose after bench press sets whether the men took 8 g of citrulline malate or a placebo. Lasting size comes from weeks of training volume, not from the pump.
What does a pump pre-workout do?
A pump pre-workout supplies nitric oxide precursors such as citrulline, usually with no caffeine; the body uses them to make nitric oxide, which relaxes blood vessels. In a 2021 meta-analysis, 6 to 8 g of citrulline malate added about 3 reps in total across sets taken to failure. It will not give you a stimulant’s kick.
Is a stim-free pre-workout worth it?
Yes, if you train late, react badly to caffeine or already drink plenty of coffee. In a 2022 trial of 24 trained adults, a caffeine-free pre-workout raised isometric squat force over placebo about as much as the caffeinated version; only the caffeinated one raised energy ratings.
Does Ninja make a pump pre-workout?
Yes. Ninja Swole is Ninja Supplements’ stim-free pre-workout, with 7000 mg of L-citrulline malate 2:1, 1500 mg of Nitrosigine and 3200 mg of beta-alanine a scoop, and no caffeine row on its label. It costs $2.00 a scoop, or $1.70 with Subscribe and Save.
Next on the mission: when to take your pre-workout, down to the minute. And if the pump is the plan, Ninja Swole is the tub.
Sources
- Guest NS, et al. International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 2021 (several authors advise supplement companies).
- Vårvik FT, Bjørnsen T, Gonzalez AM. Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis. International Journal of Sport Nutrition and Exercise Metabolism, 2021.
- Stratton MT, et al. The influence of caffeinated and non-caffeinated multi-ingredient pre-workout supplements on resistance exercise performance and subjective outcomes. Journal of the International Society of Sports Nutrition, 2022.
- Gonzalez AM, et al. Acute Effect of Citrulline Malate Supplementation on Upper-Body Resistance Exercise Performance in Recreationally Resistance-Trained Men. Journal of Strength and Conditioning Research, 2018.
- Gonzalez AM, et al. Acute Effect of L-Citrulline Supplementation on Resistance Exercise Performance and Muscle Oxygenation in Recreationally Resistance Trained Men and Women. Journal of Functional Morphology and Kinesiology, 2023 (the lead author advises a supplement maker).
- Kalman DS, et al. A clinical evaluation to determine the safety, pharmacokinetics, and pharmacodynamics of an inositol-stabilized arginine silicate dietary supplement in healthy adult males. Clinical Pharmacology: Advances and Applications, 2015.
- Currier BS, et al. American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine and Science in Sports and Exercise, 2026.
- Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 2017.
- US Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much?
How we wrote this: we rewrote this page because “does pre-workout give you a better pump” is the search Google sends to it most (search volume from Google Ads Keyword Planner), read the position stands, the meta-analysis and the trials above, and checked every Ninja Swole and Ninja Up dose against the product labels and every price against the store on the day of writing. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
