Does L-Arginine Increase Size? Why L-Citrulline Works Better

Last updated: April 22, 2026

Key Takeaways

• L-Arginine does not meaningfully increase muscle size, height, or penis size. Meta-analyses link this to poor bioavailability and no confirmed hypertrophy effects.
• L-Citrulline raises plasma arginine levels about twice as effectively as L-Arginine, which supports stronger nitric oxide production, pumps, and performance.¹
• Studies using 6–8 grams of Citrulline Malate report up to 53% more repetitions and about 40% less soreness, without L-Arginine’s common GI side effects.¹
• Bucked Up products such as Bucked Up Pre-Workout provide 6 grams of Citrulline Malate with AstraGin to support absorption and consistent results.¹
• Switch to Bucked Up L-Citrulline to experience the bioavailability advantage and performance benefits described in this guide.¹

Why L-Arginine Fails: The Real Costs to Your Training

Poor nitric oxide production limits muscle pumps, which caps your repetitions and the training intensity you can sustain. Early fatigue during workouts slows progress in the gym and makes progressive overload harder to achieve. Athletes feel this as premature exhaustion, while people chasing height or erectile improvements often end up disappointed. Dr. Layne Norton’s comprehensive review reports that L-Arginine supplementation consistently fails to build muscle or enhance strength in resistance-trained individuals. Extensive gut and liver breakdown, mixed growth hormone study results, and no measurable hypertrophy effects sit at the core of these failures.

The Science Behind L-Arginine’s Limits and L-Citrulline’s Advantages

These failures are not just gym rumors. Multiple meta-analyses document L-Arginine’s lack of effect across several growth-related outcomes. For muscle development, systematic reviews show no hypertrophy or strength improvements in trained adults. Height changes after puberty remain minimal, and L-Arginine mainly appears in pediatric settings as a diagnostic tool for growth hormone testing, not as a growth treatment.

Research on erectile function and size tells a similar story. Clinical trials suggest L-Arginine can support erectile dysfunction through nitric oxide pathways¹, yet they show no permanent size increases. Growth hormone data often misleads people. L-Arginine can raise GH levels on paper, but it also blunts the normal exercise-induced GH response and does not create measurable growth in real-world settings.

L-Citrulline offers a different path through its kidney-based conversion into arginine. Research shows L-Citrulline raises plasma arginine levels about twice as effectively as direct arginine supplementation. In that same work, 8 grams of Citrulline Malate supported 53% more repetitions, better endurance, and roughly 40% less delayed onset muscle soreness.¹

Bucked Up focuses on clinically studied ingredients, including Citrulline Malate and pure L-Citrulline. Compare our L-Citrulline options to find the formulation that matches your training style.

L-Citrulline vs. L-Arginine: How Bucked Up Formulas Use the Science

Aspect	L-Arginine	L-Citrulline	Bucked Up Products
Absorption	L-Arginine has an oral bioavailability of approximately 70% (68±9%)	Kidney conversion that supports about 2x higher plasma arginine PMID:32708306	Includes AstraGin to support uptake1
NO/Pump	Inconsistent	Improved performance and pump outcomes (see rep and soreness data above) PMID:32708306	6 g Citrulline Malate (Bucked Up / Woke AF); 4 g pure L-Citrulline plus Nitrosigine (Mother Bucker)
Side Effects	GI issues, headaches	Generally mild and less frequent	Transparent labels, GMP-certified manufacturing

L-Citrulline works alongside a solid diet and training plan by supporting blood flow and nutrient delivery.¹ Bucked Up formulations use 6 grams of Citrulline Malate in a 2:1 ratio, which supports nitric oxide production and the Krebs cycle through the malate component.¹ The Bucked Up Pre-Workout label confirms 6 grams of Citrulline Malate per serving.

How to Use L-Citrulline: Practical Dosing, Timing, and Product Checklist

This simple checklist helps you apply the research in your own routine.

• Take 6–8 grams of Citrulline Malate about 60 minutes before weight training sessions to align peak arginine levels with your workout.¹
• Use 3–6 grams of pure L-Citrulline daily for steady endurance and cardiovascular support, especially on non-lifting or lighter training days.¹
• Choose products with full ingredient disclosure and absorption aids such as AstraGin, and avoid proprietary blends so you can verify your actual dose.
• Track changes in repetitions, pump quality, and post-workout soreness to see how your body responds and adjust your dose within the supported range.

Most people tolerate L-Citrulline well, although some experience mild gastrointestinal discomfort or interactions with blood pressure medications.¹ Bucked Up Pre-Workout provides 6 grams of Citrulline Malate plus AstraGin for strong bioavailability.¹ See the full ingredient panel to confirm the dosing described here.

Busting Myths, Managing Risks, and Respecting Supplement Limits

L-Arginine myths continue despite clear scientific pushback. No over-the-counter supplement directly increases height, penis size, or muscle size in a way that bypasses normal physiology, and growth hormone spikes from L-Arginine do not reliably create hypertrophy. For adolescents, any potential growth effects remain unproven and should be evaluated with a medical professional. L-Arginine can bring headaches and digestive issues, while L-Citrulline generally shows a more favorable safety profile, although individual responses still vary.

Supplements work as amplifiers for smart training and nutrition, not as replacements. Consistent resistance training, enough daily protein, and progressive overload remain the main drivers of muscle development, with nitric oxide support playing a supporting role.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Real Scenarios: Matching Bucked Up Citrulline to Your Goals

Different Bucked Up formulas fit different experience levels, caffeine needs, and pump preferences.

• Beginners: Start with Bucked Up Pre-Workout (6 g Citrulline Malate, 200 mg caffeine) to gauge your response to both the pump ingredients and a moderate stimulant dose.¹
• High caffeine tolerance: If 200 mg feels light, Woke AF offers the same 6 g Citrulline Malate with 333 mg caffeine for a stronger energy boost.¹
• Advanced athletes: Mother Bucker uses 4 g pure L-Citrulline plus Nitrosigine, which targets nitric oxide through a slightly different pathway that some experienced users prefer for pump intensity.¹
• Stimulant-sensitive: Non-Stim Pre-Workout supplies the full 6 g Citrulline Malate with zero caffeine, so you can focus on pumps without jitters.¹

Choose products with clear labels and ingredient transparency so you can match the formula to your training style and stimulant comfort level.

FAQ

Does L-Arginine increase height at 17?

L-Arginine provides little to no height increase after puberty because growth plates usually close during adolescence. In pediatric medicine, L-Arginine mainly appears in diagnostic testing for growth hormone deficiency, not as a treatment to extend height. Genetics, nutrition, sleep quality, and overall hormonal balance play a much larger role in determining final adult height.

What’s the best Citrulline dose for muscle pumps?

As noted in the dosing checklist above, research supports 6–8 grams of Citrulline Malate taken about 60 minutes before resistance training.¹ That dose usually provides around 3.4–4.5 grams of pure L-Citrulline when using a standard 2:1 ratio formulation, although responses can vary with body weight in lbs, training intensity, and baseline nitric oxide levels.

L-Arginine vs Citrulline: Which is better?

L-Citrulline generally delivers stronger bioavailability and performance support than L-Arginine.¹ L-Arginine undergoes significant breakdown in the gut and liver, while L-Citrulline bypasses much of this through kidney conversion. This process creates higher plasma arginine levels and more consistent nitric oxide production. Studies, including PMID:32708306, report greater exercise performance improvements with L-Citrulline supplementation.¹

Does L-Arginine increase penis size permanently?

L-Arginine does not create permanent penis size increases. It may support erectile function by improving nitric oxide production and blood flow, yet these changes relate to vascular function, not structural growth. Any size-related effects fade when supplementation stops because they depend on ongoing nitric oxide support.

Is daily L-Citrulline supplementation safe?

Daily L-Citrulline intake in the 3–6 gram range appears safe for most healthy adults, with few reported side effects. People with low blood pressure, kidney issues, or those using blood pressure medications should talk with a healthcare provider before starting. Pregnant and breastfeeding women should avoid L-Citrulline due to limited safety data.

How much L-Citrulline is in Bucked Up products?

Bucked Up pre-workouts contain 6 grams of Citrulline Malate in a standard 2:1 ratio, which yields about 3.4 grams of pure L-Citrulline per serving. Label confirmation. Mother Bucker includes 4 grams of pure L-Citrulline plus additional nitric oxide support from Nitrosigine. Label confirmation. All of these formulations use AstraGin to support absorption and bioavailability.¹

When should I take L-Arginine for growth?

L-Arginine supplementation does not perform well for growth-focused goals because of poor bioavailability and a lack of measurable hypertrophy effects. A more evidence-based approach uses L-Citrulline about 60 minutes before training to support nitric oxide production and exercise performance. For general health support, consistent L-Citrulline intake with meals or as directed on product labels works better than chasing timing around L-Arginine.

Conclusion: Move Past L-Arginine and Use Evidence-Based Citrulline

Current research shows that L-Arginine falls short for meaningful changes in muscle size, height, and other growth-related outcomes. L-Citrulline’s stronger bioavailability and documented performance benefits position it as a more evidence-based option for nitric oxide support.¹ Bucked Up focuses on science-backed dosing of Citrulline Malate and pure L-Citrulline. Make the switch from L-Arginine today and see how evidence-based supplementation can support your training.

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