Total Nitric Oxide is a pre-workout blend built around L-citrulline and beetroot, two of the most researched natural compounds for supporting nitric oxide production during exercise. Nitric oxide is the molecule that signals blood vessels to relax and widen, improving blood flow and oxygen delivery to working muscles. One scoop before training; the 236g tub is a 20-serving supply.

Better Pumps. More Oxygen. Faster Recovery. Nitric Oxide Does All Three.

Your muscles need oxygen, nutrients, and blood flow delivered at the right time - and nitric oxide is the molecule that makes it happen. A natural vasodilator produced by the body, nitric oxide signals blood vessels to relax and widen, improving circulation to working muscles during exercise. Total Nitric Oxide from Onnit is formulated to support your body's own NO production, using a research-backed combination of L-Citrulline, Beet Root, and supporting compounds.

Athletic Performance and Sexual Health. Same Pathway.

Beyond athletic performance, nitric oxide plays a well-documented role in sexual health. The same vasodilation mechanism that improves blood flow to muscles also supports erectile function - nitric oxide is the primary signalling molecule responsible for smooth muscle relaxation in penile tissue, a mechanism that underpins how most prescription ED medications work at a physiological level (PMID: 17143052). For men looking to support both gym performance and sexual health through the same pathway, Total Nitric Oxide addresses both simultaneously.

Four Research-Backed Ingredients

L-Citrulline is converted to L-Arginine in the kidneys, which then serves as the direct precursor to nitric oxide synthesis. Supplementing with citrulline has been shown to be more effective at raising plasma arginine levels than arginine supplementation itself, supporting both aerobic and anaerobic performance (PMID: 20386132).

Beetroot (Beta vulgaris) is naturally rich in dietary nitrates, which the body converts to nitric oxide via the nitrate-nitrite-NO pathway. Research shows beetroot supplementation can reduce the oxygen cost of exercise and improve time-to-exhaustion (PMID: 19661447).

L-Arginine AKG (Alpha-Ketoglutarate) provides a further substrate for nitric oxide production while also supporting energy metabolism during high-intensity training (PMID: 16923826).

Vitamin C plays a supporting role in protecting nitric oxide from oxidative breakdown, helping to maintain bioavailable NO levels during and after exercise (PMID: 12527670).

Frequently Asked Questions

What does Total Nitric Oxide do?
It supports the body's own nitric oxide production, the molecule responsible for widening blood vessels and improving blood flow to working muscles during exercise.

What is L-citrulline and why is it included?
L-citrulline converts to L-arginine in the kidneys, the direct precursor to nitric oxide. Research shows citrulline raises plasma arginine levels more effectively than arginine supplementation itself.

What does beetroot do?
Beetroot is naturally rich in dietary nitrates, which the body converts to nitric oxide via a separate pathway. Research shows it can reduce the oxygen cost of exercise and improve time to exhaustion.

How do you take it?
One scoop mixed with water, taken before training. The 236g tub provides 20 servings.

Who should check before taking it?
Consult your doctor before use if you're pregnant, nursing, taking medication - particularly blood pressure medication - or have a pre-existing medical condition.

Supply and delivery

236g tub, 20 servings. Mix one scoop with water and take before training. Stocked and shipped from Dublin - order before 4pm for same-day dispatch.