Herbalife Niteworks: The Real Nobel Prize Science Behind It

By Dogus Dilan, Herbalife Independent Wellness Coach  ·  Last updated 12 August 2026

Niteworks combines L-arginine and L-citrulline, the two amino acids central to Louis Ignarro’s 1998 Nobel Prize-winning discovery of nitric oxide as a cardiovascular signalling molecule. When the product launched, some scientists questioned why citrulline was included alongside arginine — but subsequent pharmacokinetic research has actually shown citrulline raises blood arginine levels roughly twice as effectively as arginine itself, since it bypasses the gut metabolism that breaks arginine down. The formally authorised claims on this specific product are for Vitamin C, Vitamin E and Folic acid; the broader nitric oxide research is genuine, fascinating science, presented here as ingredient context.

The Discovery That Won a Nobel Prize

In 1998, pharmacologist Louis Ignarro shared the Nobel Prize in Physiology or Medicine with Robert Furchgott and Ferid Murad for discovering that nitric oxide (NO) — a simple, short-lived gas — acts as a signalling molecule that relaxes and widens blood vessels. This uncovered an entirely new mechanism in cardiovascular biology, and Ignarro specifically identified nitric oxide as the “endothelium-derived relaxing factor” that had puzzled researchers for decades. It’s genuinely one of the most significant discoveries in 20th-century vascular biology.

Since 2003, Ignarro has served on Herbalife’s Scientific Advisory Board, where he worked directly on formulating Niteworks — a dietary supplement built around the amino acids that feed the body’s own nitric oxide production pathway.

Why Both L-Arginine and L-Citrulline — Not Just One

L-arginine is the direct raw material your body’s nitric oxide synthase enzyme uses to produce NO. The problem, discovered in later research, is that a large portion of oral arginine gets broken down by an enzyme called arginase in the gut wall before it ever reaches the bloodstream — this is called first-pass metabolism.

L-citrulline sidesteps this problem entirely. It isn’t broken down the same way in the gut, and the body converts it back into L-arginine through the kidneys. A 2008 pharmacokinetic study published in the British Journal of Clinical Pharmacology directly tested this: oral L-citrulline raised plasma L-arginine levels in a dose-dependent way, and a later review in Nutrients concluded citrulline is roughly twice as effective as arginine itself at raising blood arginine, specifically because of that lower first-pass loss.

This is worth mentioning because when Niteworks first launched, some in the scientific community — including Ferid Murad, who shared Ignarro’s own Nobel Prize — publicly questioned whether the citrulline addition was scientifically necessary. The pharmacokinetic research that followed actually supports the combination on genuine biochemical grounds, rather than settling the question either way at the time.

What the Broader Research Shows — And What’s an Authorised Claim

A 2019 review in Nutrients looking at oral arginine and citrulline’s effects on blood pressure found real, measurable effects in the reviewed trials — arginine supplementation was associated with blood pressure reductions of around 5.4/2.7 mmHg, comparable in size to what’s typically seen from diet and exercise changes, while citrulline’s effect was described as “more questionable” but in a similar range.

It’s important to be precise here: this is real, peer-reviewed research on the ingredients as a category, not a formally authorised EU health claim for this specific product. The claims that do appear on Niteworks’ own UK label are for Vitamin C, Vitamin E and Folic acid — genuine, EFSA-authorised claims in their own right, covered below.

What’s Actually an Authorised Claim on This Product

The Role of L-Taurine and Lemon Balm

L-taurine is an amino acid found throughout the body’s tissues, and lemon balm (Melissa officinalis) provides the citrus flavour here — both are genuine formulation choices, though it’s worth noting neither carries a specific authorised EU health claim on this product’s label.

Ingredients

L-arginine, flavour enhancer (citric acid), maltodextrin, flavouring, L-taurine, L-citrulline, calcium-L-ascorbate, DL-alpha tocopheryl acetate, sweetener (sucralose), lemon balm extract (Melissa officinalis L., 0.4%), pteroylmonoglutamic acid, anti-caking agent (silicon dioxide).

How to Use It

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Niteworks

150g · 15 servings · Suitable for vegetarians and vegans · Citrus flavour from lemon balm extract.

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Sources & References

• Britannica — “Louis Ignarro: Biography, Nobel Prize, & Facts.”
• Schwedhelm, E. et al. (2008). “Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism.” British Journal of Clinical Pharmacology, 65(1), 51-59. PubMed
• Bahri, S. et al. (2019). “The Effects of Oral L-Arginine and L-Citrulline Supplementation on Blood Pressure.” Nutrients, 11(7), 1679. MDPI
• Herbalife Nutrition Advisory Boards — “Lou Ignarro.”
• Herbalife Nutrition — official UK product label and nutritional information.

This is a food supplement, not a medicine. Not intended for use by children, pregnant or breastfeeding women. If you take medication, particularly for blood pressure or heart conditions, or have a medical condition, consult a healthcare professional before use.