Most citrulline products on the market are in fact citrulline malate, a mix of citrulline and malic acid, usually in a 2 to 1 ratio. In 5 g of citrulline malate, only about 3.3 g is citrulline; the rest is malic acid, a much cheaper molecule. Labels show the total weight, rarely the actual citrulline content.

Here there is no malate at all: every gram is L-citrulline. Gram for gram, this powder therefore provides about one and a half times as much citrulline as a 2 to 1 citrulline malate: that is the figure to look at when comparing labels.

Citrulline is a non-essential amino acid found notably in watermelon, which gave it its name, Citrullus. Once absorbed, it is converted into arginine by the kidneys. Arginine is the direct precursor of nitric oxide, a molecule involved in the dilation of blood vessels, and therefore in blood flow to the muscles during exercise.

Why not take arginine directly? Because ingested arginine is largely broken down in the gut and liver before it reaches the bloodstream. Citrulline bypasses this step and, paradoxically, raises arginine levels better than arginine itself.

Kyowa Quality® is a Japanese standard for producing amino acids by fermentation. The process is neither chemical nor animal-based: it relies on micro-organisms grown on a plant substrate.

This has two consequences: very high purity, with an impurity profile checked batch by batch, and a product suitable for vegetarians and vegans, which is not the case for every amino acid on the market. The same standard is used for the citrulline in the brand’s Pure Workout, which gives the range its consistency.

Pure powder allows free dosing, which is its advantage over capsules. Commonly used amounts are 3 to 6 g about thirty minutes before training; Nutripure itself indicates 7 g a day, one and a half scoops (scoop included), so the 220 g bag gives around thirty servings. It dissolves easily in a large glass of water and has a pleasant, slightly tangy taste.

It is a product for athletes, mainly used in weight training and endurance sports, for the feeling of muscle pump and for repeated efforts. A satisfaction survey by Nutripure among its customers reports longer or better sustained efforts: these are self-reported data, not clinical measurements. Citrulline does not replace progression, sleep or diet.

Nutripure’s Pure Workout already contains citrulline alongside other actives: taking both would simply double the dose. Pure powder suits people who build their own mix; the complete formula suits those who want a single step. Browse our citrulline and amino acids sections to compare.

Herba Barona has been a food supplement shop at 10 rue Théophile Roussel, Paris 12th, since 2006: open Tuesday to Saturday, 9.30 am to 6.30 pm, near Ledru-Rollin and Bastille metro stations.