L-Citrulline is a non-essential amino acid, first isolated from watermelon (its name comes from citrullus, Latin for watermelon). Unlike most amino acids, its job isn't to build muscle tissue directly. Its job is to act as a precursor to L-arginine, which is itself the direct building block for nitric oxide, the molecule responsible for relaxing and widening blood vessels. More nitric oxide means more blood flow to working muscle, which shows up as the "pump" during a set and better delivery of oxygen and nutrients while you train.
How L-Citrulline Works
Eating arginine directly is a surprisingly inefficient way to raise blood arginine levels, most of it gets broken down in the gut and liver before it ever reaches circulation, a process called first-pass metabolism. Citrulline sidesteps this problem entirely. It's absorbed intact, converted into arginine primarily in the kidneys, and research suggests it may also inhibit arginase, the enzyme responsible for breaking arginine down, giving it a real edge over supplementing with arginine on its own. A study found that combining oral L-citrulline with L-arginine raised plasma arginine levels more effectively in the first hour than L-arginine alone, evidence for exactly this mechanism.1
Why PUMP Uses The Pure Form
Most pre-workouts on the market use citrulline malate, citrulline bound to malic acid, usually in roughly a 2:1 ratio, rather than pure L-Citrulline. The practical difference is dosing. A scoop of citrulline malate contains meaningfully less actual citrulline than the same weight of the pure form, because part of that weight is the malate. PUMP takes the other approach: 8g of straight L-Citrulline, so the full stated amount is active ingredient, not diluted by a binding compound, one of the highest citrulline doses in any pre-workout on the market.
How Much Do You Actually Need?
Effective doses in citrulline and exercise research typically sit in the 6-8g range, taken as a single dose around 30-60 minutes before training. Below that, particularly under 3g, studies tend to struggle to show a meaningful effect, there simply isn't enough substrate to move the needle on arginine and nitric oxide production. PUMP's 8g dose sits at the upper end of what's actually been studied, and because it's the pure form, that's 8g of citrulline itself.
L-Citrulline FAQs
Eddie's take: "I wanted a pre-workout that didn't rely on a stimulant to feel like it was doing something. PUMP's citrulline dose is honest, no hiding behind a proprietary blend, you know exactly what you're getting and how much."
Maximum pump. Zero stimulants.
Beast Pharm PUMP is built around 8g of pure L-Citrulline per serving, the premium form of citrulline for maximum nitric oxide production and one of the highest doses in any pre-workout on the market.† Alongside Betaine Anhydrous, Taurine, Epicatechin, CellFlo6™, Pine Bark Extract, and AstraGin® for absorption.
No caffeine. No crash. No compromise on the pump.
Most stim-free pre-workouts are just underdosed citrulline and a prayer. PUMP is the real thing: built for evening training, stimulant-free days, or anyone who knows the pump is driven by blood flow, not caffeine.
Developed and approved by Eddie Hall, World's Strongest Man.
†L-Citrulline at 8g per serving supports nitric oxide production and blood flow to working muscles.
Directions
Mix 1 scoop (15g) with 250ml to 350ml ofwater.
Consume approximately 20-30 minutes prior to workout.
Do not consume more one serving in any 24 hour period.
Ingredients
L-Citrulline, Betaine Anhydrous, Taurine, Epicatechin, Green Tea Leaf Extract (Camellia sinesis) (as CellFlo6™), Pine Bark Extract, Astragalus membranaceus Extract (root) & Panax notoginseng Extract (root) (as AstraGin®), Flavouring, Citric Acid, Anti-caking agent (Aerosil®, Sipernat®), Sweetener (Sucralose).
NET WT. 450g. No artificial colours.
Warnings
Please consult your physician prior to use (especially if you have a medical condition). Not recommended for anyone under the age of 18. Do not take this product if you are pregnant or breast feeding. If you are taking any medication consult your doctor before taking this product. Do not exceed the suggested use. Keep out of the reach of children. This product is not intended to diagnose, treat, cure, or prevent any disease or illness. Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle.
Allergens
Manufactured in a facility that processes celery/celeriac, crustaceans, fish, milk, mustard, peanuts, soya, gluten, egg, lupin, molluscs, nuts, sesame and sulphur dioxide.
Delivery
All UK orders are shipped using a 1-2 working day service.
Free Tracked 24 shipping is available on all orders over £25, for orders under £25 shipping is charged at £4.99
Orders placed before 1pm on weekdays are shipped the same day.
Orders placed at weekends and bank holidays will be processed on the next working day.
Europe - Please allow 5 - 10 business days for delivery. Orders under 150 EUR - including shipping costs - will not incur any customs or VAT charges.
Rest of the World - Please allow 7 - 14 business days for delivery.
DHL EXPRESS WORLDWIDE - 1 - 3 business days.
All orders are shipped tracked - a tracking link will be provided in your shipping confirmation email.
Additional Charges
Customers may incur VAT charges and Customs Duty specific to their country. The buyer assumes responsibility for any importation costs. If customs and duty fees imposed by your country are not paid, we cannot accept responsibility for the items. It is essential to familiarize yourself with your country's regulations regarding the importation of goods. If an item is confiscated due to regulations, we are not liable, and any resulting charges will be the customer's responsibility. For information regarding return shipping costs, please refer to our Refund Policy.
Suzuki, T., Morita, M., Hayashi, T., & Kamimura, A. (2017). The effects on plasma L-arginine levels of combined oral L-citrulline and L-arginine supplementation in healthy males. Bioscience, Biotechnology, and Biochemistry, 81(2), 372-375. https://doi.org/10.1080/09168451.2016.1230007
This article is for informational purposes and is not medical advice. Consult a healthcare professional before starting any new supplement, particularly if you have an existing health condition, are pregnant or breastfeeding, are under 18, or are sensitive to stimulants.
