Herbalife Niteworks®: Night-time Nitric Oxide Support — UK Guide
Herbalife Niteworks® is a night-time powder supplement built around L-arginine and L-citrulline, two amino acids the body uses to produce nitric oxide (NO) — a signalling molecule involved in blood vessel function. It was originally developed with input from Dr. Louis Ignarro, who shared the 1998 Nobel Prize in Physiology or Medicine for nitric oxide research. This guide covers what’s actually in it, what the evidence says, and — importantly — who should check with a doctor before using it, since its main ingredient does interact with certain medications.
Quick Summary
- What it is: A 10g powder serving containing 5.16g L-arginine, 0.21g L-citrulline, 0.30g L-taurine, plus vitamin C, vitamin E and folic acid.
- How to use: Mix 2 scoops (10g) with 250ml cold water and drink before bed. 15 servings per 150g canister.
- Important: Not intended for children, pregnant or breastfeeding women. If you take medication or have a medical condition — especially heart medication, blood pressure medication, or erectile dysfunction medication — consult a healthcare professional before use.
- Science link: Developed with input from Nobel Laureate Dr. Louis Ignarro, a paid member of Herbalife’s Nutrition Advisory Board.
- Where to buy: Available on myherbastore.co.uk.
On this page
What Is Niteworks®?
Niteworks® is a lemon-flavoured powder mixed with cold water and taken before bed. Its main active ingredients are L-arginine and L-citrulline — amino acids that serve as building blocks for the body’s own nitric oxide production — alongside L-taurine, vitamin C, vitamin E and folic acid. It’s suitable for vegetarians and vegans and is flavoured with lemon balm extract rather than artificial flavouring.
The Ignarro Connection, Honestly Explained
Dr. Louis Ignarro shared the 1998 Nobel Prize in Physiology or Medicine, alongside Robert F. Furchgott and Ferid Murad, for discovering that nitric oxide acts as a signalling molecule in the cardiovascular system. Since 2003, Ignarro has worked with Herbalife as a paid member of its Nutrition Advisory Board and helped develop the formulation of Niteworks® and the wider Herbalife cardiovascular product line.
In the interest of transparency: this is a commercial consulting relationship, not an independent scientific endorsement. Herbalife’s own advisory board materials include the disclosure that “the Nobel Foundation has no affiliation with Herbalife and does not review, approve or endorse Herbalife products.” Ignarro’s Nobel Prize recognises his foundational research into nitric oxide biology generally — it does not constitute a clinical endorsement of Niteworks® specifically.
The Science: L-arginine, L-citrulline & Nitric Oxide
L-arginine is a conditionally essential amino acid and a direct precursor to nitric oxide, which relaxes and widens blood vessels. L-citrulline is converted to L-arginine in the kidneys, providing a second route to the same pathway. According to the NIH Office of Dietary Supplements, typical dietary arginine intake from food is around 4–5g/day, and research on supplemental arginine for athletic performance specifically has shown mixed, generally modest results — this is a nutrient with real physiological relevance, but not a guaranteed performance or health outcome from supplementation alone.
The rationale for night-time timing reflects the idea that supporting the nitric oxide pathway before sleep — when the body is naturally at rest and blood pressure typically dips — may complement the body’s overnight vascular recovery processes, though this specific claim about Niteworks® as a combined formula has not been independently, publicly validated through peer-reviewed clinical trials that we can point to.
Nutritional Data
Per 10g serving (2 scoops), as listed on the official UK product label:
| Nutrient | Per serving | % RI |
|---|---|---|
| Vitamin E | 20mg α-TE | 167% |
| Vitamin C | 100mg | 125% |
| Folic acid | 200µg | 100% |
| L-arginine | 5.16g | — |
| L-taurine | 0.30g | — |
| L-citrulline | 0.21g | — |
Safety & Who Should Avoid It
This is the most important section on this page. L-arginine works through the same nitric oxide pathway as several common cardiovascular medications, and combining them can cause blood pressure to drop to unsafe levels. Do not start Niteworks® without speaking to a doctor first if any of the following apply to you:
- You take nitrate medication for angina or chest pain (e.g. nitroglycerin, isosorbide mononitrate/dinitrate)
- You take erectile dysfunction medication, including sildenafil (Viagra), tadalafil (Cialis) or vardenafil (Levitra) — combining these with L-arginine can cause blood pressure to fall too low
- You take blood pressure medication of any kind (ACE inhibitors, beta-blockers, calcium-channel blockers) — L-arginine can amplify their blood-pressure-lowering effect
- You take potassium-sparing diuretics (e.g. spironolactone, amiloride) — combining with L-arginine may raise blood potassium to unsafe levels
- You have low blood pressure, a history of heart attack, or any other cardiovascular condition
- You are pregnant, breastfeeding, or under 18 — the official product label states Niteworks® is not intended for these groups
If none of the above applies to you, Niteworks® is formulated for general adult use, but as with any supplement affecting blood vessel function, it’s still worth mentioning to your GP if you’re on any regular medication.
Herbalife Niteworks® — 150 g
Night-time L-arginine, L-citrulline and L-taurine powder with vitamin C, E and folic acid. Lemon flavour, vegan and vegetarian friendly. 15 servings.
- 5.16g L-arginine
- 15 servings
- Vegan & vegetarian
How to Use It
- Shake the canister gently before each use.
- Measure two scoops (10g) into 250ml of cold water, sparkling water, or juice.
- Stir until fully dissolved.
- Drink before bedtime as part of your evening routine.
- Do not exceed the recommended one serving per day.
Related Reading
Frequently Asked Questions
What is Herbalife Niteworks® used for?
It’s used to support the body’s own nitric oxide production, mainly via L-arginine and L-citrulline, taken as an evening routine before bed.
Is Niteworks® safe to take with blood pressure or heart medication?
Not without medical advice. L-arginine can have an additive effect with nitrates, PDE5 inhibitors (like Viagra or Cialis), and blood pressure medications, potentially causing blood pressure to drop too low. Speak to your doctor before combining Niteworks® with any of these.
Who is Dr. Louis Ignarro?
He is a pharmacologist who shared the 1998 Nobel Prize in Physiology or Medicine for discovering nitric oxide’s signalling role in the cardiovascular system. He has worked as a paid consultant and Nutrition Advisory Board member for Herbalife since 2003, helping formulate Niteworks® and other cardio products. The Nobel Foundation itself has no affiliation with, and does not endorse, Herbalife products.
When is the best time to take Niteworks®?
Before bedtime, as directed on the label — this is when the formula is intended to be used, mixed with 250ml of cold water.
Is Niteworks® suitable for vegans?
Yes, it’s formulated to be suitable for both vegetarians and vegans.
Can pregnant or breastfeeding women take it?
No — the official product label states Niteworks® is not intended for use by children, or by pregnant or breastfeeding women.
Sources & References
- Mayo Clinic. L-arginine — Drug interactions. mayoclinic.org
- NIH Office of Dietary Supplements. Dietary Supplement Fact Sheets. ods.od.nih.gov
- Britannica. Louis Ignarro — Biography, Nobel Prize & Facts. britannica.com
- Herbalife Nutrition Advisory Boards. Lou Ignarro. hnadvisoryboards.com
- Nutritional and usage data as disclosed on the official Niteworks 150g product page.
