Two tubs sit on the shelf. Both say 8,000mg of citrulline on the front.

One contains 8,000mg of citrulline. The other contains roughly 4,500mg.

Neither brand is lying. Neither is breaking a rule. And unless you know what to look for, you will pay the same money for a little over half the ingredient.

This is the single most useful thing you can learn about reading a pre workout label, and almost nobody in the UK market will explain it to you, because almost nobody in the UK market benefits from you knowing it.

The two forms, plainly

L-Citrulline is the amino acid on its own. If a label says 8,000mg L-Citrulline, you are getting 8,000mg of citrulline.

Citrulline malate is that same amino acid bonded to malic acid, a compound involved in energy metabolism. If a label says 8,000mg citrulline malate, part of that weight is malic acid, not citrulline.

That is the entire trick. The number on the tub is the weight of the whole compound, not the weight of the active part.

So how much of it is actually citrulline?

Here is where the industry gets slippery, and where I have to be straight with you rather than give you the tidy answer.

Citrulline malate is usually sold as "2:1", which sounds precise but is not. The ratio can refer to the molecular relationship or the weight relationship, and the label rarely says which. Depending on the interpretation, 2:1 citrulline malate works out somewhere between about 56% and 72% citrulline by weight, with the figure most commonly cited in ingredient literature sitting around 56.6%.

Run that across the numbers on real tubs:

 

Even taking the most generous reading, every citrulline malate figure on a label overstates the citrulline you actually receive. At the commonly cited 56.6%, it overstates it by more than 40%.

And notice what happens at the bottom of that table. A pre workout advertising 1,500mg of citrulline is delivering under a gram. That is not a small dose. That is barely a dose at all.

Does the malate do anything?

Fair question, and the honest answer is not the one the industry gives.

The pitch for malate is that it feeds into the Krebs cycle and supports energy production, so you get citrulline plus a bonus. It sounds good. The evidence for it is weak.

A systematic review concluded that adding malate to citrulline has not been shown to enhance exercise performance (Gough et al., European Journal of Applied Physiology, 2021). A more recent controlled trial compared citrulline malate against the same dose of pure L-Citrulline in 43 resistance trained adults and found no advantage for the malate form (Martin-Olmedo et al., International Journal of Sport Nutrition and Exercise Metabolism, 2024).

So on current evidence, the malate is not paying rent. It is occupying weight on the label that could have been citrulline.

One honest caveat, because this page is supposed to make you better at reading claims rather than just better at trusting mine: that same 2024 trial found neither form outperformed placebo in its particular protocol, which was low to moderate volume resistance training. Citrulline research is not unanimous. What it does consistently suggest is that if you are going to take it, the dose needs to be a real one.

Why does everyone use citrulline malate then?

Three reasons, and none of them are about you.

Cost. Citrulline malate is cheaper per gram than pure L-Citrulline. You are paying for malic acid at citrulline prices.

The label looks better. 6,000mg reads as a stronger formula than 3,400mg, and the first number is the one allowed on the front of the tub.

The research is quotable. The most cited resistance training study on this ingredient used 8g of citrulline malate and recorded significantly more bench press repetitions from the third set onward, plus around 40% less muscle soreness at 24 and 48 hours ([Pérez-Guisado & Jakeman, 2010](→ https://journals.lww.com/nsca-jscr/fulltext/2010/05000/citrulline_malate_enhances_athletic_anaerobic.9.aspx)). Brands cite that study constantly. Very few mention that the 8g of citrulline malate used in it supplied roughly 4,500mg of actual citrulline, which means a tub with 3,000mg of citrulline malate is at about a third of the dose in the study it is quoting at you.

How to read any pre workout label from now on

Four steps, ten seconds:

1. Find the form. "L-Citrulline" or "citrulline malate"? If it just says "citrulline", assume malate.
2. If it says malate, multiply by 0.57 for a conservative estimate of the actual citrulline.
3. Compare that number to the research, which has generally used doses in the 6,000 to 8,000mg range of citrulline malate, so roughly 3,400 to 4,500mg of actual citrulline.
4. If it is inside a proprietary blend, you cannot do any of this, and that is the point of the blend.

Do that across a shelf and the market rearranges itself in front of you.

Where BigDaddy sits

BigDaddy Pre Workout uses 8,000mg of pure L-Citrulline per 20g serving. Not citrulline malate. There is no conversion to do, no ratio to interpret and no malic acid taking up room. The number on the label is the amount of citrulline in the scoop.

For context against the study everyone cites: 8,000mg of pure L-Citrulline is above the roughly 4,500mg of citrulline that the Pérez-Guisado trial actually delivered.

We chose it because the malate does not appear to earn its place, and because a formula that needs an asterisk to explain its headline number is not a transparent formula. The full dose breakdown, including the [dual caffeine system](→ /blogs/pre-workout/strongest-pre-workout-uk) and how the whole thing compares against the rest of the UK market, is set out in our [best pre workout UK guide](→ /blogs/pre-workout/best-pre-workout-uk).

Read the form. Do the multiplication. Then decide who has been straight with you.

Get to work.

FAQ

Is citrulline malate the same as L-Citrulline? No. L-Citrulline is the amino acid on its own, so the label figure is the amount of citrulline you get. Citrulline malate is citrulline bonded to malic acid, so only part of the stated weight is citrulline. Commonly cited figures put 2:1 citrulline malate at around 56.6% citrulline by weight, though interpretations range up to about 72%, meaning a citrulline malate label always overstates the actual citrulline dose.

How much citrulline is in citrulline malate 2:1? Between roughly 56% and 72% of the stated weight, depending on whether the ratio is read as molecular or by weight, with around 56.6% the most commonly cited figure. So 8,000mg of citrulline malate 2:1 supplies approximately 4,500mg of citrulline, 6,000mg supplies approximately 3,400mg, and 4,000mg supplies approximately 2,260mg.

Which is better, L-Citrulline or citrulline malate? On current evidence, pure L-Citrulline is the more straightforward choice. A systematic review found no demonstrated performance benefit from adding malate to citrulline, and a 2024 controlled trial found no advantage for citrulline malate over the same dose of pure L-Citrulline in resistance trained adults. Since malate occupies weight that could be citrulline, the pure form delivers more of the active ingredient per gram.

What is a good dose of citrulline in a pre workout? Research on resistance training has typically used around 8g of citrulline malate, which supplies roughly 4,500mg of actual citrulline. When comparing labels, convert citrulline malate figures to actual citrulline before judging the dose. BigDaddy Pre Workout contains 8,000mg of pure L-Citrulline per 20g serving.

Why do most pre workouts use citrulline malate instead of L-Citrulline? Citrulline malate costs less per gram than pure L-Citrulline and produces a larger number on the label, since the stated weight includes the malic acid. Most published resistance training research also used the malate form, which makes it easier to cite even when the actual citrulline dose in the product falls well short of the dose used in the study.

Does BigDaddy Pre Workout use citrulline malate? No. BigDaddy Pre Workout uses 8,000mg of pure L-Citrulline per 20g serving, so no conversion is required to work out the actual citrulline content. BigDaddy Pre Workout is made by BigDaddy Sports, a UK company, and sold at bigdaddypre.com.