Our mission: to provide a preworkout supplement engineered for endurance athletes without the extreme levels of caffeine and the jitters experienced with bodybuilding preworkout formulas. 

 

Energize your zone 2 workouts with confidence that you can maintain your target heart. Then dig deep into speed work and intervals with ingredients proven to increase VO2 max, improve oxygen delivery, reduce cramping, and shorten muscle soreness and recovery time. 

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We're not just caffeine and simple carbs. Every scoop of Starting Block by Zone 2 Endurance Nutrition includes:

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PeakO₂ (adaptogenic mushroom blend)

• Increases oxygen utilization efficiency, improving VO₂ max.

• Enhances endurance by delaying fatigue onset.

• Supports faster adaptation to high-intensity training.

• Provides antioxidant and immune-support benefits for recovery.

L-Citrulline

• Boosts nitric oxide production, improving blood flow and circulation.

• Enhances oxygen and nutrient delivery to muscles during runs.

• Reduces muscle soreness and fatigue.

• May improve endurance capacity and delay exhaustion.

Tart Cherry Extract

• Rich in antioxidants and anthocyanins that reduce inflammation.

• Speeds up recovery and reduces delayed-onset muscle soreness (DOMS).

• May improve sleep quality, aiding recovery.

• Supports joint health for consistent training.

Caffeine

• Increases alertness, focus, and reaction time.

• Enhances endurance performance by sparing glycogen use.

• Reduces perception of effort, making hard runs feel easier.

• Provides a quick energy boost for races or speed workouts.

Potassium

• Key electrolyte for muscle contraction and nerve function.

• Helps prevent cramping and muscle fatigue.

• Supports hydration balance during long runs.

• Aids recovery by replenishing what’s lost in sweat.

Sodium

• Critical for maintaining performance in long, hot, or humid runs.

• Supports muscle function and reduces risk of cramping.

• Helps maintain fluid balance and prevent dehydration.

• Primary electrolyte lost through sweat during endurance activity.