8 Best Supplements to Boost Gym Performance & Nitric Oxide

Last updated: April 22, 2026

Key Takeaways: How These 8 Ingredients Support Your Training

• L-Citrulline supports nitric oxide and gym performance through kidney conversion, with research using 6–8g doses before training.¹
• Citrulline Malate pairs L-Citrulline with malic acid to support muscle pumps and energy production during high-volume training.¹
• Nitrosigine delivers rapid vasodilation at 1.5g and can pair well with citrulline in pre-workout stacks.¹
• Beetroot extract supplies natural nitrates for sustained nitric oxide support through the nitrate–nitrite pathway, which can help endurance work.¹
• Bucked Up provides research-backed L-Citrulline dosing for performance; shop research-backed doses.¹

1. L-Citrulline: Core Nitric Oxide Support for Gym Performance

L-Citrulline supports nitric oxide production through a kidney-based conversion pathway. Unlike arginine, which undergoes significant first-pass metabolism in the gut and liver, L-Citrulline bypasses these organs and converts to arginine in the kidneys. This pathway helps maintain elevated plasma arginine and nitric oxide levels over several hours.

Research demonstrates that 8g of Citrulline Malate can increase repetitions to failure by 53% during resistance training.¹ Acute citrulline supplementation does not significantly improve endurance performance measures TTE or TTC in young healthy adults¹, so the main benefits concentrate in higher-intensity lifting rather than long-duration cardio.¹ For this style of training, an effective protocol uses 6–8g L-Citrulline taken 30–60 minutes before lifting sessions.

These research-backed doses guide Bucked Up’s formulation strategy. Bucked Up’s foundational pre-workout features 6g of Citrulline Malate, while Mother Bucker contains 4g of pure L-Citrulline stacked with Nitrosigine for more advanced athletes who want both immediate and sustained nitric oxide support.¹

2. Citrulline Malate: Pump and Endurance Support in One Ingredient

Citrulline Malate combines L-Citrulline with malic acid in a 2:1 ratio, so it supports both nitric oxide production and energy metabolism. The malic acid component participates in the Krebs cycle, which can help ATP production and reduce exercise-related fatigue.¹ This dual action makes Citrulline Malate useful for high-volume resistance training and repeated sets.

The 2:1 ratio supports good bioavailability and can reduce gastrointestinal distress that sometimes appears with very high single doses of pure L-Citrulline. Because of this ratio, the 6–8g doses used in studies actually deliver about 3.4–4.5g of pure L-Citrulline, yet performance still improves across different training styles and experience levels.¹ This pattern suggests the malic acid contributes meaningful value beyond simply carrying citrulline.

3. Nitrosigine: Fast-Acting Partner for Citrulline Stacks

Nitrosigine fills the gap when sustained nitric oxide from L-Citrulline needs a faster onset. This patented complex of arginine and silicon shows enhanced bioavailability compared with standard arginine supplements. It helps bypass some of the first-pass metabolism issues that limit arginine effectiveness, leading to noticeable nitric oxide increases within about 30 minutes.¹

The typical effective dose ranges from 1.5–3g, so it fits easily into pre-workout formulas without inflating serving size. This low dose requirement allows Bucked Up to include Nitrosigine in Mother Bucker alongside a full 4g serving of pure L-Citrulline. The combination targets multiple nitric oxide pathways: Nitrosigine supports rapid vasodilation, while L-Citrulline maintains elevated levels for 4–6 hours, covering both early-session pump and ongoing performance.¹

4. Beetroot Extract: Nitrate Support for Longer Sessions

Beetroot extract supplies dietary nitrates that convert to nitric oxide through a pathway distinct from arginine and citrulline. This nitrate–nitrite–nitric oxide route offers an alternative way to support exercise performance, especially during endurance or longer-duration efforts. Effective servings typically provide about 300–600mg of dietary nitrates.

This nitrate loading translates into measurable performance outcomes. Research indicates beetroot supplementation can improve oxygen efficiency and exercise tolerance.¹ Unlike citrulline’s relatively rapid kidney conversion, beetroot’s natural nitrate content provides a more gradual, sustained release of nitric oxide precursors over several hours. This extended window makes beetroot extract particularly useful for training sessions that last beyond 90 minutes or for endurance-focused activities where maintaining performance matters more than a short-term pump.

5. Beta-Alanine: Carnosine Support for Extra Reps

Beta-alanine supports intramuscular carnosine levels, which buffer acid buildup and can delay muscular fatigue during high-intensity exercise.¹ It does not directly raise nitric oxide, yet it pairs well with citrulline because it targets a different performance limiter. Multi-ingredient formulations containing both compounds have demonstrated superior performance benefits compared to single-ingredient approaches.¹

The standard effective dose ranges from 3.2–6.4g daily, often split into smaller servings to reduce the familiar tingling sensation. Bucked Up’s formulations account for this tolerance factor. Their foundational pre-workout uses a more moderate approach, while Mother Bucker delivers the full 6.4g dose for experienced users who prioritize endurance and do not mind the tingling as much.

6. Creatine: Everyday Strength and Power Base

Creatine monohydrate supports ATP regeneration during short, intense efforts, giving a reliable energy base that pairs well with nitric oxide support. Creatine and nitric oxide boosters act through different mechanisms, so together they address both energy supply and nutrient delivery to working muscles.

The standard protocol uses 3–5g daily, with an optional loading phase for faster saturation. Research on multi-ingredient supplements demonstrates that combining creatine with nitric oxide precursors produces additive performance benefits.¹ The energy production from creatine and the circulation support from nitric oxide work in parallel rather than competing.

7. Agmatine: Support Ingredient for Bigger Pumps

Agmatine sulfate acts as a nitric oxide synthase cofactor and may enhance the impact of other nitric oxide boosters. Doses of 1,300–2,670mg daily have been studied for neuropathic pain, and sports supplements often include lower amounts in pre-workout blends. Agmatine supports the enzymatic conversion of arginine to nitric oxide and may help extend the duration of pump effects.¹

This compound works best as a supporting player alongside citrulline and other nitric oxide precursors. Many lifters treat it as an amplifier rather than a primary driver of performance.

8. Pre-Workout Blends: Putting the Ingredients Together

Multi-ingredient pre-workout supplements bring these compounds together in one serving. Well-designed blends can combine nitric oxide boosters with creatine, beta-alanine, and focus ingredients to support several aspects of performance at once. Research indicates that well-formulated multi-ingredient supplements produce superior results compared to single-ingredient approaches.¹

Bucked Up uses transparent labeling so you can see exact doses, including 6g of Citrulline Malate in the foundational pre-workout. This clarity helps you match products to your goals and stack them confidently with standalone ingredients like pure L-Citrulline.

Building Your Nitric Oxide Game Plan

Your nitric oxide strategy should match your training style and comfort with stacking ingredients. For most lifters, L-Citrulline or Citrulline Malate at research-backed doses forms a solid foundation, since L-Citrulline’s pharmacokinetics make it roughly twice as effective as arginine for raising plasma arginine levels.

Lifters who want faster onset can add Nitrosigine for a dual-pathway approach that supports both immediate and sustained nitric oxide production. Endurance-focused athletes can layer beetroot extract on top of citrulline to extend benefits during longer sessions. Bucked Up offers dosing of science-backed ingredients, including Citrulline Malate and pure L-Citrulline; compare Citrulline Malate vs. pure L-Citrulline options.

Safety and Stacking Considerations

L-Citrulline shows an excellent safety profile at recommended doses, with mild gastrointestinal effects sometimes appearing above 10g.¹ Individuals with low blood pressure or those scheduled for surgery should use caution because of potential vasodilatory effects.¹ Within these boundaries, multi-ingredient formulations have shown enhanced benefits when combining citrulline with beta-alanine and creatine, indicating these ingredients can be stacked safely when each stays within its own tolerance range.

Bucked Up incorporates Astragin in select formulations to support absorption and bioavailability of key ingredients. This approach helps each serving deliver its intended effect while staying inside established safety margins. These statements have not been evaluated by the FDA.

Frequently Asked Questions

L-Citrulline vs. Arginine for Gym Performance

L-Citrulline generally outperforms arginine for gym performance because of its different metabolic route. Arginine experiences significant breakdown in the gut and liver, while L-Citrulline bypasses these organs and converts to arginine in the kidneys. This process produces higher and more sustained plasma arginine levels, which supports nitric oxide production and exercise performance.

Best Dose Range for Muscle Pumps

For noticeable muscle pumps, research supports 6–8g of Citrulline Malate or 3–6g of pure L-Citrulline taken 30–60 minutes before training. As covered earlier, these doses provide enough substrate for nitric oxide production while keeping gastrointestinal effects manageable for most healthy users. Bucked Up’s pre-workout formulations align with these research-backed ranges.

Daily L-Citrulline Supplementation Safety

Daily L-Citrulline intake at 3–6g appears safe for healthy individuals. Studies report minimal side effects, usually limited to mild digestive discomfort at higher intakes. People with low blood pressure or kidney disorders should consult a healthcare professional before starting regular supplementation.

Good Bucked Up Starting Point for Beginners

The foundational Bucked Up Pre-Workout offers a practical starting option. It provides 6g of Citrulline Malate, 200mg caffeine, and supporting ingredients such as beta-alanine and Alpha-GPC. This balance supports performance without extremely high stimulant content.

How Nitric Oxide Supplements Affect Athletic Performance

Nitric oxide supplements can improve athletic performance, although the impact depends on training type.¹ For resistance training, proper L-Citrulline use can increase repetitions to failure by over 50 percent, driven by better oxygen delivery and nutrient transport to working muscles.¹ The main benefits appear in high-intensity, shorter-duration efforts rather than long, steady-state endurance work.

Conclusion: Turning Research into Your Routine

L-Citrulline, Citrulline Malate, Nitrosigine, beetroot extract, creatine, beta-alanine, and agmatine each play a specific role in performance support.¹

Bucked Up’s transparent formulations deliver the research-backed doses discussed throughout this guide. Start with science-backed L-Citrulline and build your stack from there based on how you train.

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