NutraBio | Intra Fuel

NutraBio Intra Fuel Leg Day is a transparent, performance-first intra-workout built around one simple idea: if your session is long, glycolytic, and demanding, your body needs more than stimulants and flavoring. This formula uses a fully disclosed label with no proprietary blends and combines fast gastric-emptying carbohydrate, essential amino acids, hydration minerals, and non-stimulant performance cofactors to keep output high after the easy sets are over. That is the right strategy for lower-body days, high-volume hypertrophy sessions, and conditioning work where force production and focus usually fall off hardest in the second half of training.

The backbone is 25g of Cluster Dextrin® highly branched cyclic dextrin, one of the most athlete-friendly carbohydrate forms in the category. Its low osmolality supports faster gastric emptying and easier tolerance during training than heavier carb sources, so you get usable fuel without the sloshy, bloated feeling many intra carbs create. In practical terms, this means more stable training energy and less drop-off in later sets. Supporting that is a substantial amino matrix: 2,500mg leucine, 1,250mg isoleucine, and 1,250mg valine deliver the classic 2:1:1 BCAA ratio, while lysine, threonine, histidine, methionine, phenylalanine, tryptophan, and ornithine broaden the formula beyond a simple BCAA drink. Leucine at 2.5g matters because that is the lower end of the clinical range commonly associated with triggering mTOR signaling and muscle protein synthesis. The remaining EAAs help make that signal more physiologically useful by providing additional building blocks that BCAAs alone cannot fully replace.

Hydration support is also intelligently layered. Taurine at 2,000mg is a serious dose for cellular hydration and osmotic balance, helping muscle cells hold water and supporting contractile performance. Pink Himalayan salt, CocoPure™ coconut water powder, Calci-K® calcium potassium phosphate citrate, and Albion® di-magnesium malate create a multi-electrolyte profile rather than a token sprinkle of sodium. Magnesium is only 50mg elemental here, below standalone clinical magnesium dosing, but still useful inside an intra-workout because magnesium acts as a cofactor in ATP production and muscle contraction. The phosphorus and phosphate components also fit the performance goal, given phosphorus’s central role in ATP structure and buffering.

What elevates this above a standard carb-and-EAA product is the patented performance matrix. elevATP® is included at the full studied 150mg dose, with human data showing improved lower-body strength, power output, and ATP availability. Senactiv® is also dosed at the full 50mg used in research, where it has been shown to support recovery through senescent cell clearance, glycogen replenishment, and muscle regeneration signaling. NeuroFactor® is present at the exact 100mg dose used in human work showing an increase in BDNF, a neurotrophic factor tied to focus, learning, and neuronal resilience. L-DOPA from Mucuna pruriens at 150mg adds a dopamine-precursor component for drive and training intent, though this is below the broader clinical range usually discussed for direct L-DOPA applications, so it should be viewed as a supporting focus ingredient rather than the main event. AstraGin® at 50mg rounds the system out by supporting intestinal absorption and nutrient uptake, which makes sense in a formula asking your body to process carbs, amino acids, and minerals during movement.

The synergy is clear: Cluster Dextrin® supplies fuel, electrolytes and taurine improve fluid balance and muscular function, leucine-led aminos protect performance and recovery, elevATP® and Senactiv® support ATP and output, NeuroFactor® sharpens the mind-muscle side, and AstraGin® improves delivery. Just as important, NutraBio does this with full disclosure. No proprietary blends, no buried dosages, no guessing.

What to expect: on day 1, the biggest differences are steadier energy through the session, easier hydration, and less mid-workout fade. Over 2-4 weeks of consistent use, the recovery side becomes more noticeable: better repeat-session quality, less flatness during long training blocks, and more reliable performance on the sessions that usually expose weak intra-workout formulas.

How to Use NutraBio | Intra Fuel Leg Day