Nutrabio - PRE Workout Stim-Free

NutraBio PRE Stim-Free is the 2025-reformulated, max-strength all-in-one pre-workout built without a single stimulant. Not a watered-down pump product. Not a handful of ingredients at half doses wearing the stim-free label. The same architecture as the award-winning NutraBio PRE — 16g Pump Matrix, 8.3g Strength Matrix, 2.9g Nootropic and Focus Matrix, and Electrolyte and Hydration support — with caffeine and all stimulants completely removed and the nootropic stack rebuilt around non-stimulant cognitive drivers. Zero caffeine. Zero synephrine. Zero anything that elevates heart rate or requires a recovery window before sleep. Fully transparent label. No proprietary blends. 20 servings. California Prop 65 Warning applies.†

Supplement Facts — NutraBio PRE Stim-Free (Per 1 Scoop Serving)

Pump Matrix — 16g

• L-Citrulline — 10,000mg
• Arginine Nitrate (as NO3-T) — 1,650mg
• Betaine Nitrate (as NO3-T) — 1,600mg
• L-Arginine Alpha-Ketoglutarate 2:1 (AAKG) — 1,500mg
• L-Arginine — 1,250mg

Strength, Endurance and Performance Matrix — 8.3g

• CarnoSyn Beta-Alanine — 3,200mg
• Betaine Anhydrous — 2,500mg (1.5g anhydrous + 1g from Betaine Nitrate NO3-T)
• Taurine — 2,000mg

Nootropic and Focus Matrix — 2.9g

• L-Tyrosine — 1,500mg
• Alpha GPC — 600mg
• Vitacholine (Choline Bitartrate) — included in nootropic matrix
• Velvet Bean Extract (Mucuna pruriens, seed) — 250mg
• Vincamine — 20mg
• AstraGin — included as absorption enhancer

Electrolyte and Hydration Matrix — 714mg

• Calci-K (Calcium Potassium Phosphate Citrate)
• Sodium Phosphate

• Zero caffeine. Zero stimulants. No artificial colors. Fully transparent label. No proprietary blends.
• Non-GMO. Gluten-free. Third-party tested. Made in USA in NutraBio's FDA-inspected, GMP-certified facility.
• 20 servings. California Prop 65 Warning applies.

What's Inside NutraBio PRE Stim-Free — Four Matrix Breakdown

The Case for Stim-Free at This Dose Level

Most stim-free pre-workouts on the market are essentially pump products — they contain citrulline, maybe some glycerol, and call it a day. They work for blood flow but leave performance, endurance, and focus entirely to the user. NutraBio PRE Stim-Free was built on a different premise: if you remove caffeine, you replace what caffeine was doing rather than leaving a gap. That means a full-dose endurance matrix (CarnoSyn Beta-Alanine at 3.2g, Betaine at 2.5g, Taurine at 2g) for physical performance without adrenergic support, and a complete nootropic focus matrix (L-Tyrosine, Alpha GPC, Velvet Bean, Vincamine) that drives cognitive performance and mind-muscle connection through dopaminergic and cholinergic mechanisms rather than through CNS stimulation. The pump matrix is meanwhile the most aggressive in the NutraBio lineup, anchored by 10g of L-Citrulline plus 3.25g of combined NO3-T nitrates for a vasodilation intensity that competes with any stimulant pre-workout on shelves.†

Pump Matrix — 16g Total

L-Citrulline — 10,000mg. At 10g, the citrulline dose in PRE Stim-Free is at the very top of what any commercially available pre-workout delivers. L-Citrulline converts to L-Arginine in the kidneys, which in turn serves as the substrate for nitric oxide synthase (NOS) enzymes that produce nitric oxide — the vasodilatory signaling molecule responsible for smooth muscle relaxation in blood vessel walls and the resulting increase in blood flow. The superiority of citrulline over direct arginine supplementation is well-established: oral arginine is heavily degraded by intestinal and hepatic arginase before reaching the kidneys, making its contribution to plasma arginine modest. Citrulline bypasses the gut and liver intact, producing significantly larger and more sustained increases in plasma arginine and consequently nitric oxide than arginine supplementation at equivalent doses. At 10g, the citrulline dose is 2-4x what most pre-workouts include, and the resulting increase in nitric oxide production, blood flow, and muscle pump intensity is proportionally greater.†

Arginine Nitrate (as NO3-T) — 1,650mg and Betaine Nitrate (as NO3-T) — 1,600mg. Combined, these two NO3-T nitrate compounds deliver 3,250mg of dual-source dietary nitrate to the Pump Matrix — on top of the 10g citrulline, not instead of it. NO3-T is the patented, pharmaceutical-grade nitrate from Thermolife — the most studied and highest-purity dietary nitrate form in sports nutrition. Dietary nitrates are reduced to nitrite and then to nitric oxide through the enterosalivary nitrate-nitrite-nitric oxide pathway — an entirely separate NO production mechanism from the NOS-dependent pathway that citrulline supports. By activating both the NOS pathway (via citrulline/arginine) and the nitrate-nitrite-NO pathway (via NO3-T nitrates) simultaneously, PRE Stim-Free produces more total nitric oxide from more pathways than any single-mechanism approach allows. The result is more sustained, more intense vasodilation — the kind that keeps muscles visibly fuller and more vascular not just during the workout but well after.†

L-Arginine AKG 2:1 (AAKG) — 1,500mg and L-Arginine — 1,250mg. While direct arginine supplementation is less bioavailable than citrulline for NO production, the inclusion of AAKG and free-form arginine alongside 10g citrulline and 3.25g NO3-T nitrates provides additional substrate redundancy — ensuring every possible route to elevated plasma arginine and nitric oxide is saturated. AAKG's alpha-ketoglutarate component also enters the Krebs cycle as an energy substrate, contributing a mild metabolic energy support component on top of the vascular effect.†

Strength, Endurance and Performance Matrix — 8.3g

CarnoSyn Beta-Alanine — 3,200mg. CarnoSyn is the patented, sustained-release beta-alanine from Natural Alternatives International — the only form of beta-alanine with peer-reviewed human clinical research attached to its specific production process. Beta-alanine is the rate-limiting precursor to muscle carnosine — a dipeptide stored in skeletal muscle that acts as a physiological buffer against hydrogen ion accumulation during high-intensity exercise. As exercise intensity increases, hydrogen ions accumulate faster than they can be cleared, dropping intramuscular pH and impairing muscle contractile function — the mechanism behind the "burn" and the performance drop that follows. Elevating muscle carnosine through consistent beta-alanine supplementation increases the buffering capacity of muscle against this acid accumulation, extending the duration at which high-intensity performance can be sustained before fatigue-induced decline occurs. At 3.2g, PRE Stim-Free provides the minimum dose established in research as effective for elevating muscle carnosine stores — the research-threshold dose, not a cosmetic amount.†

Betaine Anhydrous — 2,500mg. Betaine (trimethylglycine) is a metabolic compound derived from beets that functions through two distinct performance mechanisms. First, it is a methyl donor in the methionine cycle, contributing to creatine biosynthesis from homocysteine — supporting the body's own creatine production capacity. Second, betaine functions as an osmolyte, drawing water into muscle cells (similar to creatine) and protecting cells against dehydration-induced cellular stress during exercise. Human research on betaine supplementation at 2.5g daily over multiple weeks has documented significant improvements in bench press power, back squat power, and total training volume in resistance-trained subjects. At the research-validated 2.5g dose, betaine is one of the most underrated performance ingredients in pre-workout formulation.†

Taurine — 2,000mg. Taurine is a conditionally essential sulfur-containing amino acid that serves as both an osmolyte (pulling water into cells for intracellular hydration) and a direct performance enhancer through multiple mechanisms. It reduces exercise-induced oxidative stress, supports mitochondrial function, modulates intracellular calcium to improve excitation-contraction coupling in muscle cells, and has been documented to extend time to exhaustion during sustained exercise at doses of 1-3g. At 2g, PRE Stim-Free provides the research-effective taurine dose for both the cellular hydration and the direct performance effects.†

Nootropic and Focus Matrix — 2.9g

This is where PRE Stim-Free differentiates itself from every other stim-free pre-workout in the NutraBio lineup and from the vast majority of competing products. Rather than leaving a cognitive vacuum where caffeine used to be, this matrix rebuilds focus through three distinct non-stimulant pathways: dopaminergic precursor supply, cholinergic neurotransmission enhancement, and cerebrovascular blood flow support.†

L-Tyrosine — 1,500mg. Tyrosine is the amino acid precursor to dopamine, norepinephrine, and adrenaline — the catecholamine neurotransmitters that govern motivation, drive, attention, and the acute stress response to physical training. During demanding exercise, catecholamine depletion is one of the mechanisms by which mental fatigue and reduced training drive occur. Supplemental tyrosine replenishes the precursor pool, supporting the brain's capacity to maintain catecholamine synthesis under the metabolic demands of intense training. At 1.5g, the dose matches the research protocols showing meaningful improvements in cognitive performance, working memory, and stress resilience during demanding conditions.†

Alpha GPC — 600mg. Alpha-glycerylphosphorylcholine is the premier cholinergic nootropic — the most bioavailable form of choline for brain uptake, with the highest documented impact on acetylcholine synthesis of any choline source. Acetylcholine is the primary neurotransmitter for motor neuron signaling, including the neuromuscular junction signals that initiate muscle contraction. In the performance context, elevated acetylcholine availability supports a stronger mind-muscle connection, more precise motor unit recruitment, and sustained neuromuscular output as training volume accumulates. At 600mg — double the dose in many competing formulas — PRE Stim-Free provides a genuinely impactful Alpha GPC dose.†

Velvet Bean Extract (Mucuna pruriens) — 250mg. Velvet Bean seed extract is standardized for L-DOPA (levodopa) — the direct biochemical precursor to dopamine that crosses the blood-brain barrier for conversion to dopamine in the central nervous system. While L-Tyrosine feeds dopamine synthesis from the amino acid stage, Mucuna's L-DOPA enters the pathway one step closer to dopamine itself, complementing tyrosine's precursor support with a more direct route. The combination of tyrosine and Mucuna extract provides comprehensive dopamine precursor availability through two different entry points in the synthesis pathway. The result is better mood, stronger drive, and more sustained motivation through training sessions — without the stimulant mechanism that caffeine uses.†

Vincamine — 20mg. Vincamine is a minor alkaloid extracted from the periwinkle plant (Vinca minor) that increases cerebral blood flow through vasodilatory effects in the brain's vasculature. More blood flow to the brain means more oxygen and glucose delivery to neural tissue during high cognitive demand — translating to sharper focus, faster reaction time, and reduced cognitive fatigue during extended training sessions. Vincamine is one of the more rarely seen ingredients in pre-workout formulation, and its inclusion at a meaningful dose reflects NutraBio's willingness to use the best available ingredients rather than the most commonly sourced ones.†

AstraGin. AstraGin is NutraBio's bioavailability enhancer of choice for this formula — a patented blend of Astragalus and Panax notoginseng extracts from NuLife Sciences, shown to upregulate intestinal transport proteins that improve the absorption of amino acids, creatine, and other active compounds. Its inclusion ensures the full 16g+ of active ingredients in PRE Stim-Free reach the bloodstream efficiently rather than being partially degraded during absorption.†

Electrolyte and Hydration Matrix — 714mg

Calci-K (Calcium Potassium Phosphate Citrate) and Sodium Phosphate provide the three primary electrolytes lost in sweat during intense training: sodium, potassium, and calcium. These minerals are required for maintaining muscle contractile function, nerve impulse transmission, and intracellular fluid balance throughout a training session. Electrolyte depletion mid-workout is a primary driver of strength decline, cramping, and reduced neuromuscular output in the later stages of long sessions — particularly relevant for anyone training in warm environments or high-intensity formats.†

Frequently Asked Questions About NutraBio PRE Stim-Free

1. Will I actually feel something without caffeine?
   Yes — and in ways that are meaningfully different from stimulant pre-workouts. The most immediately noticeable effect for most users is the beta-alanine paresthesia (the tingling sensation in the skin, particularly on the face, ears, and hands) within 10-15 minutes of taking the formula — a sign that CarnoSyn is active and muscle carnosine loading is proceeding. The pump and vascularity effects from 10g citrulline and 3.25g NO3-T nitrates are subjectively as strong or stronger than most stimulant pre-workouts, because the pump matrix is genuinely one of the most aggressive ever put in a stim-free product. The focus from Alpha GPC, Tyrosine, Mucuna, and Vincamine produces a calm, sustained mental clarity rather than the sharp, jittery alertness of caffeine — a cleaner cognitive state that many athletes find more conducive to technique-focused training. What you will not feel is the acute heart rate elevation, pre-workout anxiety, or post-workout crash that stimulants produce.†
2. Can I stack PRE Stim-Free with NutraBio Creatine Monohydrate?
   Yes — and this is one of the most practical stacks available. PRE Stim-Free does not include creatine in its formula (unlike the older version), so adding 5g of NutraBio Creatine Monohydrate directly into your PRE Stim-Free scoop adds creatine without any ingredient conflicts. The electrolyte matrix and taurine in PRE Stim-Free also support creatine uptake by maintaining the cellular hydration environment where creatine is stored. For athletes who want a complete daily performance stack, PRE Stim-Free plus creatine covers pump, endurance, focus, strength, and muscle saturation in one pre-workout drink.†
3. Who specifically benefits most from PRE Stim-Free over PRE?
   Evening and late-night trainees who cannot take caffeine within 6+ hours of sleep. Athletes who have built a caffeine tolerance and want to cycle off stimulants while maintaining training performance. Anyone sensitive to the cardiovascular effects of caffeine — elevated heart rate, anxiety, blood pressure spikes. People who stack multiple supplements and want full control over their total stimulant intake. And athletes who train twice per day and need a pre-workout for a second session where an additional 350mg caffeine would create problems. PRE Stim-Free also stacks cleanly with a fat burner or thermogenic that already contains caffeine — you get the fat loss support without compounding stimulant load.†
4. How does the new 2025 formula compare to the older PRE Stim-Free?
   Significantly upgraded. The previous formula had 6g citrulline; the 2025 version delivers 10g — a 67% increase in the anchor pump ingredient. The previous version used Agmatine and Nitrosigine for secondary pump support; the new formula replaces them with 3.25g combined NO3-T nitrates (Arginine Nitrate + Betaine Nitrate) — a more studied, more potent nitric oxide production pathway. The nootropic matrix has been expanded with Velvet Bean extract (L-DOPA source) and Vincamine (cerebrovascular blood flow) joining Alpha GPC and Tyrosine. AstraGin was added for bioavailability optimization. The new formula is more comprehensive in every matrix simultaneously.†

How to Take NutraBio PRE Stim-Free

Mix 1 scoop with 10-12oz of cold water and consume 20-30 minutes before training. New users may start with a half scoop to assess tolerance for the beta-alanine tingling sensation — this is a normal, harmless physiological response that typically diminishes with consistent daily use as muscle carnosine stores saturate. Do not exceed 1 scoop in any 24-hour period. Stacks cleanly with NutraBio Creatine Monohydrate, Base Aminos, and Magnesium Glycinate. Because it contains no stimulants, it can be taken any time of day without sleep disruption concerns.†

Why Buy at Get Yok'd

• Real-time inventory across all five Southern California stores
• Available in Burbank, Glendale, Glendale Galleria, Pasadena, and North Hollywood
• Authorized retailer of NutraBio
• One of the best loyalty programs in the supplement industry — earn rewards on every purchase
• Owned and operated by fitness enthusiasts who actually use what we sell

Who Should Not Take NutraBio PRE Stim-Free

• Not intended for use by persons under 18
• Not for pregnant or nursing women
• Consult a physician before use if you have cardiovascular disease, hypertension, or any heart condition — the NO3-T nitrates and vasodilatory ingredients meaningfully reduce blood pressure and may interact with cardiovascular medications
• Consult a physician before use if taking blood pressure medications or nitrate-based medications (nitroglycerin, PDE5 inhibitors) — dietary nitrates can potentiate the effects of these drugs
• Consult a physician before use if you have kidney or liver disease
• Consult a physician before use if taking any prescription medications
• Some individuals may experience skin tingling (paresthesia) from beta-alanine — this is harmless and normal; begin with a half scoop if concerned
• Do not exceed 1 scoop in a 24-hour period
• Drink plenty of water during use
• California Residents: This product can expose you to chemicals including Lead, known to the State of California to cause cancer. Visit P65Warnings.ca.gov/food for more information
• Keep out of reach of children

†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.