Nootropic Pre-Workout Stack

01Caffeinehuman trials

the guide

the anchor of the category: caffeine was in 86 of the 100 top-selling pre-workouts in a 2019 count (Jagim 2019), and the International Society of Sports Nutrition (ISSN) position stand on energy drinks names it, with carbohydrate, as the main performance ingredient in those drinks (Jagim 2023).

evidence: an umbrella review of 21 meta-analyses found it improved aerobic endurance, strength, muscular endurance, power, jumping and speed, with moderate-quality evidence for four of those, bigger effects on aerobic than anaerobic work, and mostly young men in the underlying studies (Grgic 2020). the ISSN position stand on caffeine finds small to moderate gains in strength, speed, jumps and sport skills, the most consistent gains in aerobic endurance, and better attention and vigilance in most people (Guest 2021). daily use wears the gain down: in 11 active adults who took it every day for 20 days, it raised peak cycling power by about 4% for the first 15 days, with the biggest lift on day one (Lara 2019).

watch for: across 24 studies it cut total sleep by 45 minutes and deep sleep by about 11 (Gardiner 2023). the position stand ties person-to-person differences in its effects on sleep and anxiety partly to genes for how it is cleared (Guest 2021). fluvoxamine stretched its half-life from 5 to 31 hours in eight volunteers (Jeppesen 1996). the energy-drink stand warns that several servings a day, or servings on top of other caffeinated drinks and foods, may lead to adverse effects (Jagim 2023). WADA's 2026 Monitoring Program lists it in competition only, and the 2026 Prohibited List says monitored substances are not prohibited.

02L-Theaninesmall human trials

the guide

the tea amino acid, paired with caffeine to soften it. taken alone it is no stimulant: in a four-arm trial of 48 adults it changed no alertness or jitteriness rating and slowed reaction time, and it blunted caffeine's rise in blood pressure (Rogers 2008).

evidence: the sport trials test the pairing, and they split. in 12 elite wrestlers, theanine alone moved no test against placebo, caffeine alone raised state anxiety, and the pair beat placebo on all five physical tests and on Stroop speed and accuracy after a wrestling-specific test (Razazan 2025); in 22 elite curlers the pair beat placebo on all three shot types, and each alone beat placebo on the take-out shot only (Yilmaz 2023). in 20 trained athletes, the pair added nothing on strength, endurance or eye-hand coordination, caffeine alone beat placebo on no strength test, and theanine alone lowered leg and back strength (Tuncer 2026). in the lab, a meta-analysis of 11 trials of tea compounds found moderate effects of the pair on alertness and attention switching in the first two hours, with caffeine's dose tending to matter more (Camfield 2014).

watch for: lab results run both ways too: at tea-like amounts in 24 people, adding theanine erased caffeine's effects on cognition and mood (Dodd 2015), and in the 48-adult trial it did not lower caffeine's jitteriness (Rogers 2008). in the wrestlers, 92% reported a racing heart on caffeine alone against 17% on the pair (Razazan 2025). the athlete results are single trials of 12 to 22 people.

03Alpha-GPCsmall human trials

the guide

a choline compound sold for power and focus, used as a prescription drug, choline alfoscerate, in some countries and as a supplement in others (Che 2025; Lee 2021). in 8 resting men, one dose raised blood choline and, at one hour, growth hormone (Kawamura 2012).

evidence: the performance trials we found of it alone are four small ones: three in men, two of them from one university group, and one in women. six days of it raised mid-thigh pull peak force against placebo in 13 college men, while an upper-body gain missed significance (Bellar 2015). in 48 college men split into four arms of 12, seven days of either dose changed no strength or vigilance score against placebo, though the lower dose gave the largest gains in jump velocity and power (Marcus 2017). one dose in 20 trained men improved Stroop scores, with no group difference in jumps, bench throws or growth hormone after exercise (Kerksick 2024). in 12 overweight or obese women, one dose raised peak and mean power over two 30-second cycling sprints, a side result of a study on heart rate variability (Barzanjeh 2022).

watch for: in the 48-man trial, serum TSH, the pituitary hormone that drives the thyroid, was lower on the higher dose than in the other groups, in blood drawn one and two hours after the first dose (Marcus 2017). in a South Korean insurance cohort of 12 million adults aged 50 and older, people prescribed it had a 43% higher ten-year stroke risk than matched nonusers, rising with longer use, an association that cannot show cause (Lee 2021). in mice with high blood lipids it promoted atherosclerosis, and it can be turned into TMAO, a metabolite tied to atherosclerosis (Wang 2021).

04L-Tyrosinesmall human trials, little gain in exercise

the guide

the amino acid the body makes dopamine and noradrenaline from (Jongkees 2015), sold in pre-workouts for focus under strain: 63 of the 100 top-selling pre-workouts listed it (Jagim 2019).

evidence: a 2024 meta-analysis of 10 comparisons from 8 studies found no effect on time to exhaustion or time trials, with moderate-quality evidence (Solon-Junior 2024). in the heat, one trial found 8 men cycled to exhaustion for longer, 80 against 69 minutes at 30 degrees C (Tumilty 2011), while five others, each in 7 or 8 people, found no physical gain (Watson 2012; Tumilty 2014; Tumilty 2020; Coull 2016; Donnan 2025). without heat it did not help a time trial after 90 minutes of cycling in 9 cyclists (Chinevere 2002), or a loaded treadmill march and the strength and power tests after it in 20 men (Sutton 2005). the meta-analysis group's own 2026 trial found 12 cyclists rode to exhaustion 16% longer after a 60-minute mental-fatigue task (Solon-Junior 2026), and in 8 soccer players over a 90-minute simulation at 25 degrees C it raised vigilance hits and cut misses, with no physical change (Coull 2015).

watch for: a review of its cognitive and behavioral studies sees little for exercise and a cognitive benefit only when stress or demand has drawn down dopamine or noradrenaline (Jongkees 2015). in a five-arm trial of 76 men kept awake about 40 hours it raised prolactin against placebo (Waters 2003), and under mock interrogation in 78 military trainees it raised anger ratings and changed no other mood score, cortisol or heart rate (Lieberman 2014).

05Taurinesmall human trials

the guide

taurine was listed in 51 of the 100 top-selling pre-workouts in a 2019 count (Jagim 2019), and it is a usual energy-drink partner for caffeine (Jagim 2023).

evidence: a 2018 meta-analysis of 10 studies found an improvement in endurance performance (effect size 0.40), with single doses doing as well as courses of up to two weeks (Waldron 2018); a 2021 review of 19 studies called the findings too limited and varied for firm conclusions (Kurtz 2021). at a dose its authors call low, taurine alone moved no test in 32 trained men (Kose 2026). with caffeine, a 2025 network meta-analysis of 12 studies ranked the pair above either alone for anaerobic capacity and reaction time, though the pair's edge over caffeine alone was uncertain on both, as was its edge over taurine alone on anaerobic capacity (Deng 2025), while in 10 people cycling in 35 degrees C heat the pair did not lengthen time to exhaustion and raised oxygen use and heat production (Aggett 2025).

watch for: a week of it left muscle taurine unchanged in 8 men, though two doses in one day raised blood taurine about 13-fold in 7 volunteers (Galloway 2008). in 48 caffeine users kept off caffeine for a day, it slowed choice reaction time and sped working-memory responses, and the authors judge caffeine, not taurine, the likely cause of energy drinks' effects on thinking (Giles 2012). in isolated rabbit hearts it shortened repolarization and brought on more ventricular arrhythmias (Ellermann 2022), an animal-heart result, not a human one.

06L-Citrullinesmall human trials

the guide

the blood-flow ingredient, sold as L-citrulline or citrulline malate and listed in 71 of the 100 top-selling pre-workouts (Jagim 2019). the body turns part of it into arginine: in 20 volunteers, a week of it raised blood arginine more than arginine itself did, and the highest dose raised urinary nitrate and cGMP, markers of nitric oxide signaling (Schwedhelm 2008).

evidence: blood flow is the selling point, and single doses and longer use gave different results. after a single dose, a meta-analysis found no change in flow-mediated dilation, an ultrasound test of how well an artery widens (Smeets 2021), though one trial it included, in 24 young adults, found flow-mediated dilation up 34% after citrulline malate against a 2% fall on placebo (Rogers 2020), and neither of two doses of citrulline malate changed it over two hours in 12 young men (Grannes 2026). over longer use, the same meta-analysis found flow-mediated dilation up 0.9 percentage points (Smeets 2021), pooling just two trials: 15 days in 30 people with coronary artery disease, and a week in the 20-volunteer trial, which on its own found no gain over baseline (Schwedhelm 2008). in older adults, 14 days raised leg blood flow during exercise by 11% in men but not in women, a gain that lost significance after adjusting for baseline diastolic blood pressure (Gonzales 2017). on performance, a 2026 meta-analysis of 30 trials of citrulline malate found a small overall gain (effect size 0.16) at low to very low certainty (Wang 2026), a 2019 meta-analysis of 12 studies found a small strength and power gain with every single study's confidence interval crossing zero (Trexler 2019), and a 2023 meta-analysis of 9 studies found no endurance effect (Harnden 2023).

watch for: a 2010 trial in 41 men reported 52.9% more bench-press repetitions in the last set, with stomach discomfort in 14.6% (Perez-Guisado 2010), while a 2023 trial in 18 trained men and women found no gain in force, repetitions or muscle oxygenation (Gonzalez 2023). in a dose-ranging study of 8 men, no load caused side effects, and at the highest loads blood arginine rose less than expected (Moinard 2008). in one 2018 trial, the researchers' own lab analysis found the citrulline malate they gave, and three of the four other products they tested, off the makers' stated ratio of citrulline to malate (Chappell 2018), and the 2026 meta-analysis asks for trials that verify what the supplement holds (Wang 2026).

07Creatinehuman trials

the guide

creatine is stored in muscle, and the store builds over days: in 31 men, muscle creatine rose about 20% after a six-day load, and by the same amount over 28 days on a smaller daily amount (Hultman 1996). the ISSN stand says that rise may help explain creatine's gains in high-intensity exercise (Kreider 2017). 49 of the 100 top-selling pre-workouts listed it (Jagim 2019).

evidence: the ISSN position stand counts over 1,000 creatine studies since the early 1990s (Kreider 2017). a 2026 network meta-analysis of 52 randomized trials of creatine, beta-alanine or both, each two weeks or longer, found creatine improved sprint, jump, repeated sprints and upper-body muscular endurance against placebo (Bai 2026). the timing trials are small: in 34 athletes, taking it before or after training made no difference over 8 weeks, and neither beat placebo (Dinan 2022), while a 2021 review reads the early evidence as leaning toward after training, without a solid conclusion (Ribeiro 2021). in 24 men split between creatine and placebo, an 8-day load added 0.9 kg of body mass against 0.1 kg and no power on a 30-second cycling sprint, while caffeine raised peak power in both groups (Marinho 2024).

watch for: caffeine is the clash on record: taken daily through a six-day load, caffeine wiped out creatine's 10 to 23% gain in knee-extensor torque in 9 men (Vandenberghe 1996), and a 2022 systematic review of 10 studies found interference in two of six studies that gave both daily, while in three of four a load did not blunt a single caffeine dose taken afterwards (Elosegui 2022). it raises serum creatinine, a routine kidney blood test: over five days in 54 men it rose in all three creatine groups and not on placebo (Trexler 2016). the position stand names weight gain as the only consistently reported side effect and reports use of up to five years as safe and well tolerated in healthy people (Kreider 2017).

the Nootropic Pre-Workout Stack lines up what trials measured on focus, power, fatigue and blood flow for seven ingredients sold in pre-workouts. no trial we found gave caffeine, L-theanine, alpha-GPC, L-tyrosine, taurine, L-citrulline and creatine all together. the Nootropic Pre-Workout Stack lists trial sizes and results for each of its seven ingredients, with no amounts. the Nootropic Pre-Workout Stack covers 7 compounds: Caffeine, L-Theanine, Alpha-GPC, L-Tyrosine, Taurine, L-Citrulline, Creatine.