Yes, many pre-workout supplements contain nitrates, which are included as performance aids for athletes and fitness enthusiasts. These supplements provide concentrated nitrates to enhance physical performance during exercise. Nitrates are naturally occurring compounds found in various vegetables. Their primary inclusion reason is to leverage the body’s natural conversion of nitrate into a powerful molecule that influences blood flow and muscle efficiency.
The Performance Mechanism of Nitrates
Nitrates function as an ergogenic aid by leveraging an alternative pathway for producing nitric oxide (NO). Once ingested, nitrate (\(NO_3\)) is absorbed and concentrated in the saliva. Bacteria on the tongue reduce the nitrate into nitrite (\(NO_2\)) via the enterosalivary circulation. This nitrite is then swallowed and converted into nitric oxide within the acidic environment of the stomach and the bloodstream. NO acts as a potent signaling molecule, causing the smooth muscle lining blood vessel walls to relax, a process known as vasodilation.
This widening increases blood flow, enhancing the transport of oxygen and nutrients to working muscles. Improved blood flow reduces the oxygen cost of exercise, leading to better endurance and reduced time to exhaustion, particularly during high-intensity exercise. The increased blood flow also contributes to the temporary sensation of a “muscle pump.”
Common Sources Found in Pre-Workout Formulas
Nitrates are listed on supplement labels in both natural and synthesized forms. The most common natural source is Beetroot Extract or Beetroot Powder, derived from the root vegetable Beta vulgaris. While foods like spinach, arugula, and celery are high in nitrates, beetroot is the most widely utilized concentrated form.
Synthetic forms provide a precise, standardized dose and often appear as specific nitrate salts, such as Sodium Nitrate or Potassium Nitrate. Some formulas also include L-Citrulline, an amino acid precursor to nitric oxide that works alongside the nitrate pathway to maximize NO availability. Patented ingredients, such as Betaine Nitrate, combine nitrate salts with other compounds for enhanced effects.
Differentiating Nitrates, Nitrites, and Nitrosamines
It is important to understand the chemical differences between nitrates, nitrites, and nitrosamines, as this is a common source of confusion regarding safety. Nitrate (\(NO_3\)) is the stable, relatively non-reactive compound found in supplements and vegetables. Nitrite (\(NO_2\)) is the intermediate molecule formed when bacteria in the body reduce the ingested nitrate.
Nitrites are more chemically active and can convert into either beneficial nitric oxide or potentially harmful nitrosamines. Nitrosamines are compounds that can form when nitrites react with amines, especially under specific conditions like high-heat cooking of cured meats preserved with nitrites. The conversion of nitrate from vegetables or supplements into nitric oxide is a natural, beneficial physiological process that is distinct from the formation of carcinogenic nitrosamines. Plant-based nitrates are often accompanied by antioxidants, which help prevent the formation of nitrosamines.
Safety Profile and Recommended Dosing
Nitrate consumption from supplements is generally well-tolerated when kept within recommended guidelines. The Acceptable Daily Intake (ADI) for nitrate, as set by health organizations, is approximately 3.7 milligrams per kilogram of body weight per day. For an average adult, effective doses for performance enhancement typically range between 300 to 1,000 milligrams of nitrate, often taken as a single bolus dose.
Common side effects are infrequent but can include mild gastrointestinal upset or headaches, which are likely due to the vasodilation effect. Timing is important, with the best results often seen when the nitrate-containing pre-workout is consumed approximately 60 to 90 minutes before exercise. Consumers should adhere strictly to the label instructions and avoid excessive use, as supplements are regulated in the US under the Dietary Supplement Health and Education Act (DSHEA).