Both L-citrulline and L-arginine help increase nitric oxide levels in the body. Nitric oxide relaxes blood vessels (vasodilation), which can:

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  Improve overall circulation
  
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  Support cardiovascular health
  
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  Help deliver oxygen and nutrients more efficiently
  

By improving oxygen delivery and waste removal (like ammonia), this combination can:

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  Help sustain energy levels during physical activity
  
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  Reduce muscle soreness post-exercise
  
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  Support overall physical performance and stamina
  

This stack is popular in fitness because it may:

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  Increase endurance and reduce fatigue
  
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  Improve muscle “pump” during workouts
  
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  Support faster recovery by improving blood flow to muscles
  

L-citrulline, in particular, is often considered more effective than arginine alone because it converts into arginine in the body and stays active longer.