The back of a pre-workout tub can look like a chemistry exam. Strange names, precise measurements in milligrams, and promises of incredible effects. But behind the marketing, these are real compounds with real effects on your body. Understanding what you're consuming helps you make better choices and get better results.
This comprehensive guide breaks down the most common pre-workout ingredients, explaining what each one does, how much you actually need, and which ones are worth your money.
Stimulants: The Energy Drivers
Caffeine Anhydrous
Caffeine is the backbone of most pre-workout supplements and the most thoroughly researched ergogenic aid available. It works by blocking adenosine receptors in your brain—adenosine normally makes you feel sleepy, so blocking it keeps you alert and energised.
Beyond just waking you up, caffeine has genuine performance benefits. Research consistently shows it can improve endurance performance by 2-4%, enhance strength output, reduce perceived exertion (making hard efforts feel easier), and improve focus and reaction time.
3-6mg per kilogram of body weight, taken 30-60 minutes before exercise. For an 80kg person, that's 240-480mg. Most pre-workouts contain 150-350mg per serving.
Other Stimulants
Many pre-workouts include additional stimulants beyond caffeine:
- Theobromine: Found in cocoa, provides milder, longer-lasting energy than caffeine
- TeaCrine® (Theacrine): Similar to caffeine but with less tolerance buildup
- Dynamine® (Methylliberine): Fast-acting stimulant for quick energy onset
- Synephrine: Derived from bitter orange, can raise heart rate and blood pressure
Pump Enhancers: Blood Flow and Muscle Fullness
L-Citrulline
L-Citrulline is an amino acid that converts to L-arginine in your kidneys, which then produces nitric oxide. Nitric oxide relaxes blood vessels, improving blood flow to working muscles. This creates the "pump" sensation bodybuilders love and may improve nutrient and oxygen delivery to muscles during training.
Research supports citrulline for reducing muscle soreness, improving high-intensity exercise performance, and enhancing the subjective feeling of a workout. It's one of the most reliably effective pump ingredients available.
6-8 grams of L-Citrulline or 8-10 grams of Citrulline Malate (a 2:1 ratio of citrulline to malic acid). Many products underdose this ingredient significantly.
L-Arginine
While arginine is the direct precursor to nitric oxide, it's actually less effective than citrulline when taken orally. Much of it gets broken down in the digestive system before reaching your bloodstream. Citrulline bypasses this issue, making it the superior choice for pump enhancement.
Glycerol
Glycerol draws water into muscle cells, creating a fuller, more hydrated appearance. It can help with heat tolerance during exercise and may enhance pumps. Look for it listed as GlycerPump®, GlycerSize®, or HydroMax®.
Nitrosigine®
This patented form of arginine bonded to silicon is designed for better absorption than standard arginine. Studies show it can improve blood flow, cognitive function, and muscle pumps. It works well even at lower doses (1.5g).
Endurance and Performance Compounds
Beta-Alanine
Beta-alanine is one of the most recognisable pre-workout ingredients because of its distinctive side effect: paresthesia, or the tingling sensation that typically affects your face, ears, and hands. While the tingles might be memorable, they're not actually related to the ingredient's effectiveness.
Beta-alanine works by increasing carnosine levels in your muscles. Carnosine acts as a buffer against lactic acid, potentially allowing you to maintain high-intensity efforts for longer before fatigue sets in. Research supports its use for exercises lasting 1-4 minutes—think high-rep sets, HIIT intervals, or middle-distance cardio efforts.
- Effective dose: 3.2-6.4g daily (can be split throughout day)
- Requires loading: Takes 2-4 weeks of consistent use to saturate muscles
- Timing doesn't matter: Effects come from accumulated use, not pre-workout timing
- Tingles are harmless but don't indicate effectiveness
Creatine Monohydrate
Creatine is arguably the most researched and effective sports supplement ever studied. It works by increasing your muscles' stores of phosphocreatine, which helps regenerate ATP (your cells' energy currency) during high-intensity efforts.
While creatine is excellent, there's debate about whether pre-workout is the best time to take it. Creatine requires consistent daily dosing to work—the timing is less important than regular consumption. Taking it in your pre-workout is convenient but no more effective than any other time.
Whether you take creatine pre-workout, post-workout, or with breakfast, consistency matters most. 3-5 grams daily is the standard effective dose. If your pre-workout includes it, you may not need additional supplementation.
Focus and Cognitive Enhancers
L-Tyrosine
L-Tyrosine is an amino acid precursor to dopamine, norepinephrine, and epinephrine—neurotransmitters involved in focus, motivation, and stress response. Supplementing tyrosine may help maintain cognitive performance under stress, which includes intense physical training.
Effective doses range from 500mg to 2g, with benefits most noticeable during challenging or stressful situations.
Alpha-GPC
Alpha-GPC is a choline compound that can cross the blood-brain barrier, potentially supporting acetylcholine production. Acetylcholine is involved in muscle contraction and cognitive function. Some research suggests Alpha-GPC may enhance power output and growth hormone secretion.
Effective doses are typically 300-600mg, though some studies use higher amounts.
Huperzine A
This compound inhibits the enzyme that breaks down acetylcholine, potentially prolonging the effects of other cholinergic compounds. It's often included in small amounts (50-200mcg) to support focus and mental clarity.
Other Common Ingredients
Betaine (Trimethylglycine)
Betaine may support power output and muscle endurance. Research results are mixed, but some studies show benefits for strength and body composition. Effective doses are around 2.5g daily.
Taurine
Despite its presence in energy drinks, taurine is actually an amino acid with calming effects. It may improve blood flow, support hydration, and reduce muscle damage. Doses of 1-3g are common.
B-Vitamins
Many pre-workouts include B-vitamins (B6, B12, niacin) for energy metabolism. While important for overall health, extra B-vitamins won't boost energy unless you're deficient. The bright yellow urine after taking pre-workout? That's usually excess B2 (riboflavin) being excreted.
Electrolytes
Sodium, potassium, and magnesium support hydration and muscle function. Their inclusion in pre-workout can help offset losses from sweating, particularly during longer or more intense sessions.
Red Flags: What to Avoid
Some products list ingredients under a "proprietary blend" that shows the total weight but not individual amounts. This often hides underdosed ingredients. Quality products disclose exactly how much of each ingredient they contain.
Beyond proprietary blends, watch out for:
- DMAA/DMHA: Banned stimulants with serious cardiovascular risks
- Undisclosed ingredients: "Energy blend" or "focus matrix" without specifics
- Excessive stimulants: Products with 400mg+ caffeine plus additional stimulants
- Unrealistic claims: No supplement will add 50lbs to your bench press
Building Your Ideal Stack
The "perfect" pre-workout depends on your goals:
- For energy and focus: Caffeine (200-300mg), L-Tyrosine (1-2g), Alpha-GPC (300mg)
- For pumps: L-Citrulline (6-8g), Glycerol (2-3g)
- For endurance: Beta-Alanine (3.2g), Citrulline (6g), Caffeine (200mg)
- For strength: Creatine (5g), Caffeine (200-300mg), Betaine (2.5g)
Many quality pre-workouts combine these ingredients effectively. Look for products that hit the clinical doses for ingredients that matter most to your goals.
The Bottom Line
Understanding pre-workout ingredients empowers you to make better choices. Not every ingredient needs to be clinically dosed for a product to be effective—but the main active ingredients should be. Caffeine, citrulline, and beta-alanine are the workhorses of most formulas; everything else is supporting cast.
When evaluating a pre-workout, check that it contains effective doses of the ingredients that matter for your goals. Don't be swayed by long ingredient lists with underdosed compounds. Quality beats quantity every time.
For more on using these products safely, check out our safety guide or learn about optimising your caffeine intake.