Pre-Workout: Evidence-Based Ingredients and Fillers

The pre-workout market is one of the most confusing in supplementation — labels full of flashy ingredients, dosages hidden in “proprietary blends” and promises that are difficult to verify. This article separates real-evidence ingredients from filler ingredients and shows you what to look for when choosing or putting together your pre-workout.

What pre-workout should do

Direct answer: An effective pre-workout must provide, in proven doses, ingredients that improve acute performance (caffeine for alertness and reduction of perception of effort; citrulline for vasodilation and muscular endurance) and/or cumulative (beta-alanine for capacity for prolonged intense effort; creatine for strength and power). Secondary ingredients can contribute, but without the main ingredients in the right dose, the product has limited value.

Ingredients with strong evidence

Caffeine — the key ingredient

• Effective dose: 3 to 6 mg/kg body weight (200 to 600 mg in most cases)
• Mechanism: adenosine receptor antagonist; increases alertness, reduces perception of effort, mobilizes fat
• Best use: 30 to 45 minutes before training
• Evidence: Robust meta-analyses for strength, power, endurance and cognition

Important variables:

• Genetics (fast vs slow metabolizers)
• Acquired tolerance
• Time of day (caffeine at night can harm sleep)

Beta-alanine — for muscular endurance

• Effective dose: 3 to 5 g/day continuously (6 to 10 weeks to saturate)
• Mechanism: increases muscle carnosine; improves H+ buffering capacity
• Best in: efforts of 60 to 240 seconds (long series, circuits, medium duration modalities)
• Effect: improves performance by 2 to 4% in these ranges

Typical side effect: paresthesia (tingling) that passes in 15–30 min, harmless.

Citrulline malate — for multiple series

• Effective dose: 6 to 8 g of citrulline malate (or 4 to 6 g of pure L-citrulline)
• Mechanism: arginine precursor; increases NO (nitric oxide) and blood flow
• Effect: improves performance in multiple sets of the same exercise (more reps in final sets)
• Evidence: consistent in acute studies

Caution: many pre-workouts contain 2 to 3 g (underdose).

Creatine monohydrate — the basis of any supplementation

• Effective dose: 3 to 5 g/day continuously
• Can be in pre-workout or consumed separately
• Doesn’t depend on timing (pre, post, fasting — whatever)
• Evidence: the most robust among all ergogenic supplements

Ingredients with moderate evidence

Taurine

• Dose: 1 to 2 g
• Effect: antioxidant, possible improvement in resistance and hydration
• Evidence: moderate and mixed

Tyrosine

• Dose: 1 to 3 g
• Effect: dopamine/noradrenaline precursor; May improve cognition under stress
• Evidence: moderate, useful in specific situations (tactical sports, high cognitive demand)

Betaine

• Dose: 2.5 g/day (chronic)
• Effect: possible improvement in strength and power; inconsistent evidence
• Evidence: moderate to weak

Caffeine + L-theanine (combination)

• Dose: 200 mg caffeine + 100–200 mg theanine
• Effect: reduces caffeine jittery, keeping you alert
• Evidence: good for cognition; benefit in physical performance is secondary

Weak evidence or marketing ingredients

Arginine isolated

• It is usually “sold” for the same role as citrulline
• Bioavailability is lower; citrulline generates more arginine in plasma than direct oral arginine
• Typical pre-workout doses (2 to 3 g) are insufficient

AAKG (Arginine alpha-ketoglutarate)

• Weak evidence
• 2000s fashion

Yohimbine

• Some effects on fat mobilization
• Risk of anxiety, tachycardia
• Low benefit/risk ratio for general pre-workout

”Proprietary Blend”

• Total sum of ingredients listed without individual dose
• Opaque label by design
• Typically hides underdosing of main ingredients
• Avoid whenever possible

Low dose amino acids (BCAA/EAA 2–3 g)

• Subtherapeutic dose
• Label filling

How to read pre-workout label

1. Check specific dose per ingredient (not proprietary blend)
2. Compare with doses of evidence from the table above
3. Caffeine must be expressed in mg
4. Beta-alanine in 3 to 5 g; below that is underdose
5. Citrulline in 6 to 8 g; below that too
6. “Exotic” ingredients (plant extracts, mixtures) are often marketed

Homemade vs commercial pre-workout

Homemade (minimum functional)

• Caffeine: 1 cup of strong coffee (~150 mg) + 1 200 mg tablet for a person weighing 80 kg
• Beta-alanine: 3 g (sachet or powder)
• Creatine: 5 g (daily dose, can be pre-workout)

Cost: low. Efficacy: high. Disadvantage: less practical.

Commercial (well formulated)

Look for: caffeine ≥200 mg, beta-alanine 3–5 g, citrulline 6–8 g, possibly creatine 3–5 g.

Cost: intermediate to high. Efficacy: high if well formulated.

Dose and practical timing

Ingredient	Dose	Timing
Caffeine	3–6 mg/kg	30–45 min antes
Beta-Alanine	3–5 g/dia	Anytime; chronic
Citrulline	6–8 g	30–60 min antes
Creatine	3–5 g/dia	Anytime; continuous
Taurine	1–2 g	20–30 min antes

When NOT to take pre-workout

• At night (caffeine compromises sleep)
• On days without training (unnecessary)
• Pregnancy, lactation, uncontrolled hypertension (be careful with caffeine)
• Individual sensitivity to stimulants
• Before very short or light workouts (low return)

Strategy to maximize long-term effect

Cycle caffeine

• 8 weeks using, 2 weeks with reduced dose (or break)
• Maintains sensitivity
• Alternatively, “caffeine-free” days once a week

Continuous Beta-Alanine

• No need to cycle
• Effect persists as long as there is supplementation

Continuous creatine

• Always daily, does not cycle

Common mistakes

Buying pre-workout with expensive proprietary blend. Most of the price goes to marketing.

Caffeine every day in a high dose. Quick tolerance, effect drops.

Pre-workout shortly before training. Caffeine needs 30–45 min to peak.

Underdose of beta-alanine and citrulline. Ingredients only take effect in the right dose.

Expect acute effect of beta-alanine. Requires 6 to 10 weeks for saturation.

Ignore hydration. Pre-workout does not replace water.

Tips used by personal trainers

• For beginners: strong coffee + daily creatine is 90% of the benefit of any commercial pre-workout
• Those who train at night should avoid caffeine or reduce it a lot; theanine can help
• Ethical recommendation: transparent about dose and evidence of each ingredient; avoid selling “magic” pre-workout
• Deficit athlete may benefit more from caffeine due to its effect on alertness and effort capacity
• “If the pre-workout doesn’t have caffeine in dose and beta-alanine + citrulline, it’s filler” — useful initial filter

Key Takeaway Points

• Caffeine, beta-alanine, citrulline and creatine are the core ingredients with evidence
• Doses matter: caffeine 3–6 mg/kg, beta-alanine 3–5 g/day, citrulline 6–8 g
• Proprietary blend hides underdosage of the main ones; avoid
• Homemade pre-workout (coffee + beta-alanine + creatine) delivers maximum efficiency
• Cycling caffeine maintains sensitivity over time

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Additional reading:

• Pre-workout caffeine: dose per body weight
• Beta-alanine: dose and timing
• Creatine monohydrate: evidence-based guide
• Does thermogenic work? Evidence