SteelFit Steel Fuel: A Fully Disclosed Pre-Workout With Flexible Dosing

One scoop for 150mg caffeine, two scoops for 300mg and the full label. SteelFit built Steel Fuel so your pre-workout scales with the session instead of locking you into one number. Stevia sweetened, naturally colored, fully disclosed.

SteelFit is back on our radar with Steel Fuel, a new pre-workout dropping next month that replaces Steel Pump as the brand's flagship pump-and-energy formula. SteelFit built its name on Steel Whey, Steel Pump, and Steel Burn, and founder Rob Kaufman tells us the brand today runs on the idea of "Still Fit. Through Every Season of Life." Anyone can take their products, but their core is 30 and up: people who still train hard but whose schedules, careers, and families have changed how and when they get that training in.

Steel Fuel is Now the SteelFit Pre-Workout

One naming note before we get into the formula: Steel Fuel used to be the name of SteelFit's BCAA supplement. That product has been retired, and Steel Fuel is now SteelFit's pre-workout instead. It takes over the slot that "Steel Pump" held when we first covered it back in 2019. But don't worry, despite the name change, this formula still has tons of pump:

Clinically-Dosed Peak ATP, Nitrosigine, Citrulline, Betaine, and More!

The formula leans on two branded pump ingredients we haven't seen a ton of recently, PEAK ATP and Nitrosigine, stacked alongside a full 9 grams of citrulline malate. SteelFit also built in a flexible dosing system: 1 scoop delivers 150mg of caffeine for lighter or everyday training, while 2 scoops bring the full 300mg caffeine dose and the complete ingredient panel. Every ingredient and amount is disclosed on the label at both serving sizes.

Steel Fuel launches in two flavors, Cherry Slush and Tropical Punch, both naturally flavored, naturally colored, and sweetened with stevia only. We'll have Kaufman on the podcast to talk through the formula soon. Today, let's get into the formula:

SteelFit Steel Fuel Ingredients

The amounts below reflect the full 2-scoop serving. If you're caffeine sensitive, consider one scoop and cut these doses in half:

• L-Citrulline DL-Malate 2:1 - 9,000mg

  L-Citrulline is a non-essential amino acid that the body converts into L-arginine, the substrate for nitric oxide production. Citrulline supplementation raises arginine levels more reliably than arginine itself, since it largely avoids the gut and liver breakdown that limits oral arginine's effectiveness. Steel Fuel uses the DL-malate form at a labeled 2:1 ratio, meaning roughly two parts citrulline to one part malate.

  On performance, a systematic review and meta-analysis focused specifically on perceived exertion, muscle soreness, and blood lactate after exercise found favorable trends for citrulline across these measures.^[1] At the individual study level, one trial in resistance-trained women found citrulline malate significantly increased completed repetitions in both upper-body and lower-body exercise compared to placebo, with a 21% increase in total lower-body reps.^[2]

  Compare to 6g pure citrulline research

  With the 2:1 ratio, 9g of citrulline malate provides roughly 6g of L-citrulline. That's a dose with direct human performance data behind it. In a randomized crossover trial, 6g of pure L-citrulline daily for seven days improved severe-intensity cycling tolerance from 589 to 661 seconds, accelerated oxygen-uptake kinetics, and modestly increased total work compared to placebo.^[3]

  Higher-dose citrulline malate has also been studied. A 2025 trial gave resistance-trained men either 8g of pure L-citrulline or 12g of a verified 2:1 L-citrulline DL-malate material daily for six weeks. The 12g citrulline malate dose supplied 8.4g of actual L-citrulline, so a bit more than we have here. Both citrulline groups significantly improved total upper-body repetitions to failure compared to placebo, while the citrulline malate group also had significantly greater post-exercise nitric oxide metabolites than placebo.^[4]

  The latter study used chronic daily supplementation rather than a single pre-workout dose, so it doesn't establish that more citrulline malate is acutely better, but more over time definitely seems like a winner. Still, Steel Fuel's 9g dose puts the amount of L-citrulline right at a 6g dose that's already produced known performance gains in humans.

  Great start, and we're not at all done with blood flow yet:

• Nitrosigine® Inositol-Stabilized Arginine Silicate - 1,500mg

  

  Nitrosigine pairs arginine with silicon and inositol in a stabilized complex, and it's one of the two branded ingredients we're glad to see SteelFit bring back into rotation. A pharmacokinetic study found that Nitrosigine produced a greater than 70% increase in plasma arginine exposure compared to an equivalent dose of arginine hydrochloride, with less variability between subjects,^[5] and an earlier safety and pharmacokinetic trial established that a 1,500mg daily dose raises arginine, silicon, and nitric oxide markers without safety concerns.^[6]

  Since Steel Fuel pairs Nitrosigine with citrulline malate in the same Performance & Blood Flow Complex, it's worth noting that researchers have tested this exact combination directly: a study comparing Nitrosigine (1.5g) and citrulline malate (8g) found both separately improved flow-mediated vasodilation compared to placebo.^[7] So why not combine them?

  Another crossover trial using the same 1,500mg dose found reduced markers of exercise-induced muscle damage (creatine kinase and myoglobin) along with increased blood flow and perceived energy over a 4-day supplementation period.^[8]

  Nitrosigine also has a cognitive angle: in one crossover study, 1,500mg improved complex reasoning task completion times by 28% to 35% compared to baseline and placebo.^[9]

  We haven't seen as much Nitrosigine in new formulas lately, as the market has shifted back to citrulline, but it's great to see them both together. To close off the trifecta, we have one last mechanism:

• PEAK ATP® Adenosine 5'-Triphosphate Disodium - 450mg

  PEAK ATP is the second branded ingredient here that we're excited about, and Steel Fuel's 450mg dose sits above the 400mg used in most of the published research. A review of oral ATP supplementation summarized its ergogenic potential as reducing fatigue and increasing strength, power, and blood flow across the available trials.^[10]

  

  In one placebo-controlled trial, 2 weeks of 400mg daily dosing increased post-exercise ATP levels and improved measures of muscle excitability and power output following a repeated sprint bout.^[11] Even a single acute dose improved performance and physiological response during lower-body resistance training in one trial of recreationally trained men.^[12]

  Muscle Growth Gains, Too!

  ATP's potential isn't limited to acute workout performance. In a 12-week double-blind trial of resistance-trained men, 400mg of ATP daily alongside a periodized lifting program produced greater gains in lean body mass (4.0kg vs. 2.1kg), quadriceps muscle thickness (9.4% vs. 4.9%), and total strength (55.3kg vs. 22.4kg) compared to placebo.^[13] That makes Steel Fuel's 450mg dose especially interesting for athletes using the product consistently, since it exceeds the dose used in this longer-term resistance-training study.

  Note that most of the strongest ATP research uses a loading protocol of 1 to 2 weeks of daily dosing rather than measuring a single first-time dose, so the biggest benefits likely show up with consistent use rather than a one-off pre-workout use.

• Beta-Alanine - 3,200mg

  Tingle time:

  Beta-alanine is the rate-limiting building block for muscle carnosine, which helps buffer the accumulation of hydrogen ions during hard exercise. Unlike many pre-workout ingredients, beta-alanine isn't really about what happens from today's dose. Its benefits build as repeated supplementation raises muscle carnosine over several weeks.

  Steel Fuel provides 3.2g at the full two-scoop serving, putting it squarely within the dosing range used throughout the foundational beta-alanine literature. An early meta-analysis covering 15 studies and 360 participants found that beta-alanine supplementation improved exercise outcomes overall, with the clearest benefits during efforts lasting roughly 60 to 240 seconds, where muscular acid accumulation becomes especially relevant.^[14] A much larger follow-up meta-analysis incorporating 40 studies and 1,461 participants likewise found a significant overall ergogenic effect from chronic beta-alanine supplementation.^[15]

  

  There's direct precedent around this dose as well. In one 28-day study, subjects transitioned to 3.2g of beta-alanine daily for the final 22 days of supplementation, and the beta-alanine group significantly improved its physical working capacity at the neuromuscular fatigue threshold compared to placebo.^[16]

  The familiar beta-alanine "tingles", or paresthesia, are temporary and dose-dependent rather than a sign that the ingredient is suddenly working. The real goal is consistent daily intake and gradual carnosine loading, making Steel Fuel's full 3.2g serving a well-supported place to be.

• Betaine Anhydrous - 2,500mg

  Betaine, also known as trimethylglycine, is an osmolyte the body uses to help cells manage water balance under stress, including the metabolic stress of training. Like beta-alanine, betaine's research base is built on chronic daily use rather than single-dose effects.

  A 2024 systematic review and meta-analysis of chronic betaine supplementation on exercise performance found favorable effects across the pooled trials.^[17]

  For instance, a six-week study in experienced resistance-trained men used exactly 2.5g of betaine per day alongside a periodized lifting program. Compared with placebo, betaine increased bench press training volume, improved body composition, and significantly increased arm cross-sectional area, with the authors concluding that chronic supplementation improved work capacity and several measures related to muscular adaptation.^[18,19] Cholewa's group later tested the same 2.5g daily dose during resistance training in young women, where betaine produced significantly greater reductions in body-fat percentage and fat mass than placebo, while training volume also showed a favorable trend.^[20] Steel Fuel therefore lands directly on one of the most repeatedly studied daily betaine doses rather than merely including a token amount.

  A pharmacokinetic study of a 14-day betaine loading protocol found that serum betaine levels rise steadily with daily dosing and stay elevated during that loading window,^[21] reinforcing that daily, ongoing use is what the research actually supports rather than a single pre-workout serving.

• Taurine - 1,000mg

  

  Taurine is a sulfur-containing amino acid concentrated in muscle, heart, and brain tissue, where it supports cell volume regulation and antioxidant defense. Unlike beta-alanine and betaine, taurine's exercise research does include acute, single-dose data.

  A 2025 meta-analysis pooling 23 randomized trials on single-dose taurine found small-to-moderate improvements in exercise performance overall, with the clearest benefits in aerobic endurance, strength and power, and agility tasks, and no significant dose-response relationship within the 1 to 6 gram range commonly studied.^[22] Steel Fuel's 1,000mg falls within that studied range. This is sometimes used to take a bit of the "edge" off the caffeine too, but there's additional support for that later.

• Alpha-GPC 50% Alpha-Glyceryl Phosphorylcholine - 300mg

  Alpha-GPC is a choline-delivery compound that crosses into the brain and is a precursor for acetylcholine, the neurotransmitter tied to focus and mind-muscle communication, with this form providing roughly 40% choline by weight.^[23] An acute supplementation trial found Alpha-GPC improved cognitive performance measures in healthy men.^[24]

  The evidence for direct physical performance benefits is more mixed at this dose range. One trial comparing 250mg and 500mg doses over a week found elevated serum choline in both groups, but no significant difference from placebo in isometric strength or psychomotor vigilance.^[25] The cognitive and focus case for Alpha-GPC is better supported at these amounts than a direct strength or power claim, which is fine -- we have plenty of ingredients (above) for power and strength, this is here for focus.

• Caffeine Anhydrous - 300mg (150mg per 1-scoop serving)

  Caffeine works primarily by blocking adenosine receptors in the brain and body, which otherwise build up during exercise and promote fatigue. The International Society of Sports Nutrition's position stand on caffeine and exercise performance concludes that caffeine can acutely enhance many aspects of performance, with small-to-moderate benefits appearing across most but not all studies.^[26] A 2024 umbrella meta-analysis of meta-analyses similarly found caffeine supports both muscular strength and endurance, though the size of that effect varies by study and population.^[27]

  

  This is exactly where Steel Fuel's 1-scoop and 2-scoop options do real work. Individual caffeine response varies widely, and having a 150mg option lets someone dial in a lighter dose for an easy session or a caffeine-sensitive day, while 2 scoops deliver a fuller 300mg dose more in line with harder training.

• Ashwagandha (Withania somnifera) Root Extract 5% Withanolides - 300mg

  Ashwagandha is one of the better-studied adaptogenic herbs, with research spanning stress management, recovery, and exercise performance. In Steel Fuel, the 300mg dose makes the most sense as a chronic stress-support ingredient to help ease the effects of the caffeine hit.

  This dose also sits at the lower end of a range with clinical support for stress management. A 2022 systematic review and meta-analysis of randomized controlled trials found that ashwagandha significantly reduced both stress and anxiety compared with placebo, with its dose-response analysis identifying favorable effects on stress in the 300 to 600mg/day range.^[28] As with several other ingredients in Steel Fuel, this is a benefit that makes more sense with consistent use than from judging a single pre-workout dose.

  There's also an interesting performance side to ashwagandha, although the best resistance-training research has generally used more than Steel Fuel provides. In an eight-week randomized trial, resistance-training men took 300mg of a 5% withanolide root extract twice daily, for 600mg/day total. Compared with placebo, the ashwagandha group gained significantly more bench-press strength, leg-extension strength, arm and chest muscle size, while also showing greater improvements in body-fat percentage and testosterone.^[29] Steel Fuel provides half that daily amount, so we'd view its 300mg more conservatively as a solid adaptogenic dose with potential performance upside rather than equating it directly with the 600mg training studies.

• L-Theanine - 200mg

  L-Theanine is an amino acid found in tea leaves that's commonly paired with caffeine to smooth out the jittery edge of stimulants. A systematic review of L-theanine's effects on stress and anxiety management found support for its calming effects when taken as an isolated supplement.^[30]

  

  More importantly for Steel Fuel, there's actual research behind combining theanine with caffeine. A systematic review and meta-analysis of acute human trials found moderate effects in favor of the caffeine-theanine combination during the first two hours after dosing, particularly for alertness and attentional-switching accuracy.^[31]

  That makes the 200mg theanine here a logical counterbalance to Steel Fuel's stimulant load, supporting focused stimulation rather than simply piling more intensity onto the formula.

• Coconut Water Powder - 500mg

  Coconut Water Powder is a natural, potassium-dominant electrolyte source that rounds out Steel Fuel's Hydration Support blend. A recent comparison of rehydration strategies after exercise-induced fluid loss found coconut water performs comparably to other common rehydration options.^[32] At 500mg, this is a small fraction of what a full serving of coconut water provides, so its role here is more of a natural-ingredient nod than a significant hydration dose on its own.

• Pink Himalayan Salt - 100mg

  Pink Himalayan Salt is a part of the Hydration Support blend that provides sodium shown in the nutrient area up top. It's primarily sodium chloride with trace amounts of other minerals, and its inclusion supports the electrolyte and hydration angle of the formula alongside the coconut water powder.

• BioPerine® Black Pepper (Piper nigrum) Fruit Extract - 5mg

  BioPerine is a standardized black pepper extract used across the supplement industry as an absorption enhancer, and 5mg is the standard dose for that purpose. The classic research behind this use comes from a human and animal study showing that piperine, black pepper's active compound, increased the bioavailability of co-administered curcumin by up to 2000% in humans.^[33] That research was done with curcumin specifically, not with the actives in Steel Fuel, so it demonstrates the general mechanism rather than a tested effect on this formula's other ingredients.

• Electrolytes: Calcium, Magnesium, Sodium, and Potassium

  

  Steel Fuel rounds out its electrolyte profile with small amounts of calcium (as calcium citrate, 10mg), magnesium (as magnesium glycinate, 10mg), sodium (as sodium citrate and pink Himalayan salt, 98mg), and potassium (as potassium citrate, 57mg). Each of these sits at 4% of the daily value or less, so this isn't meant as a significant source of any single mineral. These four all play basic, well-established roles in muscle contraction, nerve signaling, and fluid balance, and their presence here is best understood as filling out the hydration and electrolyte theme already established by the coconut water powder and pink Himalayan salt rather than as a standalone selling point.

• Natural Flavors, Stevia, and Beet Root Powder

  Steel Fuel's Other Ingredients list is short by design: natural flavors, stevia extract, beet root powder for color, and silicon dioxide as a standard anti-caking agent. SteelFit's own marketing leans into this, positioning the stevia-only sweetener system (no sucralose, no Ace-K) and the natural coloring from beet root powder as part of a "clean formula" pitch aimed at avoiding the artificial-sweetener taste some stimulant products carry. We can't verify taste from a spec sheet, but the ingredient choices themselves are consistent with that positioning.

Flavors Available

Steel Fuel launches in two flavors, Cherry Slush and Tropical Punch, both built on the same natural-flavor, stevia-only sweetener system described above.

Here's an up-to-date list of all flavors of SteelFit Steel Fuel:

SteelFit's own consumer testing rates Cherry Slush at 3 out of 5 for sweetness, 3 out of 5 for tartness, and 4 out of 5 for fruitiness.

How to Use

• When to take it: SteelFit designed Steel Fuel's dosing around when and how hard you're training, whether that's an early morning session, a lunch-break workout, or a harder training day that calls for the full serving.
• Assess: Start with 1 scoop (150mg caffeine) if you're assessing your tolerance or training lighter, and move up to 2 scoops (300mg caffeine) for harder sessions once you know how you respond.

Who It's For

• The 30-and-up lifter balancing training with a full life: SteelFit built Steel Fuel around the customer who still trains seriously but whose career, kids, or schedule now shape when and how they can get to the gym.
• Anyone who wants control over their caffeine intake: The 1-scoop and 2-scoop options give caffeine-sensitive users and heavy trainers alike a way to dial in their dose without needing two different products.

Conclusion: A Fully Disclosed Comeback

Steel Fuel marks a real changeover for SteelFit's pre-workout lineup, not just a new flavor or a label refresh. The brand retired the Steel Fuel name from its BCAA lineup and handed it to this new formula, which now takes over the role Steel Pump played in the catalog. The formula backs that up with a legit upgrade: a full 9g of citrulline malate, a return to two branded pump ingredients in Nitrosigine and PEAK ATP, and a flexible 1-scoop or 2-scoop dosing system that lets caffeine intake scale with the session instead of locking everyone into one number.

The fully-disclosed ingredient blend is supported by an all-natural flavor, sweetener, and color system that rounds out a formula showing a serious upgrade rather than a repackaging exercise or minor update.

It's been a few years since we last covered SteelFit in depth, and it's good to see the brand back with something worth digging into. We're excited to have Rob on the podcast to tell his story (there was some work with "Fungies" along the way). Sign up for SteelFit brand alerts on PricePlow to know the moment Steel Fuel is available, and check the price comparison below once it's live.