Pre-workout supplements are the most popular category in sports nutrition. They promise more energy, better pumps, sharper focus, and increased endurance. Some deliver on those promises. Others are glorified caffeine pills with proprietary blends designed to hide under-dosed ingredients.
This guide breaks down what actually works in a pre-workout, the dosages backed by research, when to take it, potential side effects, and who might want to skip it entirely.
I have spent more money on pre-workouts over the past decade than I would like to admit. I have tried everything from the basic stuff you grab at Walmart to limited-edition flavors from boutique brands that cost $55 a tub. Through all of that trial and error — and a few genuinely terrible experiences with under-dosed products that did nothing — I have learned to read labels like a detective. The single biggest lesson: if a pre-workout hides its doses behind a “proprietary blend,” it is almost always because the doses are not worth advertising. Every good pre-workout I have ever used printed its exact ingredient amounts right on the label.
TL;DR: A good pre-workout should contain caffeine (150-300mg), citrulline malate (6-8g), and beta-alanine (3.2g+) on a transparent label — skip anything with proprietary blends. Take 20-30 minutes before training, avoid within 6 hours of bedtime, and cycle off periodically to maintain caffeine sensitivity.
The Key Ingredients That Actually Work
Not all pre-workout ingredients are created equal. Here are the ones with strong scientific support, along with the clinically effective dosages you should look for on the label.
Caffeine
What it does: Increases alertness, reduces perceived effort during exercise, delays fatigue, and may enhance power output.
Effective dose: 3-6mg per kg of body weight, taken 30-60 minutes before training. For a 180-pound man, that’s roughly 150-300mg.
What to know: According to a position stand by the International Society of Sports Nutrition (ISSN), caffeine is the most proven performance-enhancing ingredient in existence, with decades of research supporting its ergogenic effects. It works for both strength and endurance activities. However, tolerance builds quickly — if you drink 3 cups of coffee daily, you’ll need a higher dose to feel the same effect. Consider cycling caffeine (2 weeks on, 1 week off) to maintain sensitivity.
Key finding: According to the ISSN position stand on caffeine and exercise performance (Guest et al., 2021), caffeine at 3-6mg/kg body weight is the most effective ergogenic dose, with higher doses providing no additional benefit and increasing side effect risk.
Citrulline Malate
What it does: Converts to arginine in the body, increasing nitric oxide production. This widens blood vessels, improving blood flow to working muscles — the mechanism behind the “pump.”
Effective dose: 6-8 grams of citrulline malate (or 3-4g of pure L-citrulline).
What to know: This is where many pre-workouts fall short. A clinical dose is 6-8g, but many products contain only 3-4g and hide it in a proprietary blend. If you see “citrulline” listed but no specific dose, or a dose under 6g, you’re likely getting an under-dosed product. A 2010 study by Perez-Guisado and Jakeman published in the Journal of Strength and Conditioning Research found that citrulline malate reduced muscle soreness by up to 40% after high-volume resistance exercise.
Beta-Alanine
What it does: Increases carnosine levels in muscle, which buffers acid buildup during high-intensity exercise. This means more reps before the burning sensation forces you to stop.
Effective dose: 3.2-6.4 grams daily (this is a saturation-based ingredient like creatine — it doesn’t need to be taken immediately before training, but most people take it as part of their pre-workout).
What to know: According to a meta-analysis published in Amino Acids by Hobson et al. (2012), beta-alanine is most effective for exercises lasting 1-4 minutes — think high-rep sets, supersets, and circuit training. It’s less impactful for pure strength work (sets of 1-5 reps). The tingling sensation (paresthesia) is harmless and temporary, though some people find it uncomfortable. It subsides as your body adapts.
Creatine Monohydrate
What it does: Replenishes ATP for short, explosive efforts. Increases strength, power, and muscle volume.
Effective dose: 3-5 grams daily.
What to know: Many pre-workouts include creatine, but often at sub-clinical doses (1-2g). Since creatine works on saturation, you can take it any time — it doesn’t need to be pre-workout specifically. If your pre-workout contains less than 3g, supplement separately. For a deeper dive, read our article on when to take creatine.
L-Theanine
What it does: An amino acid found in tea that promotes calm focus without sedation. Paired with caffeine, it smooths out the energy curve — reducing jitters and anxiety while maintaining alertness.
Effective dose: 100-200mg, typically in a 1:1 or 2:1 ratio with caffeine.
What to know: This is an underrated ingredient. If caffeine makes you anxious or gives you a harsh crash, adding L-theanine transforms the experience. Research published in Nutritional Neuroscience confirms that the combination of L-theanine and caffeine improves both speed and accuracy of attention, while reducing susceptibility to distracting information. Not all pre-workouts include it, but those that do tend to provide a cleaner, more focused energy.
Betaine (Trimethylglycine)
What it does: May enhance power output and support muscle protein synthesis.
Effective dose: 2.5 grams daily.
What to know: The evidence for betaine is moderate — some studies show small improvements in strength and body composition, while others show no effect. It’s a reasonable addition but not essential. You also get betaine from dietary sources like beets and spinach.
| Ingredient | Primary Effect | Clinical Dose | Evidence Rating | Common Under-dosing? |
|---|---|---|---|---|
| Caffeine | Energy + focus + performance | 150-300mg | Very Strong | Rarely |
| Citrulline Malate | Pumps + blood flow + recovery | 6-8g | Strong | Very common (3-4g typical) |
| Beta-Alanine | Endurance (acid buffering) | 3.2-6.4g daily | Strong | Sometimes (1.6g common) |
| Creatine Monohydrate | Strength + power + volume | 3-5g daily | Very Strong | Often (1-2g common) |
| L-Theanine | Calm focus (pairs with caffeine) | 100-200mg | Moderate-Strong | Often omitted entirely |
| Betaine | Power output + body comp | 2.5g daily | Moderate | Sometimes |
I want to talk about two ingredients I personally look for that do not get enough attention. The first is L-theanine, which I discovered by accident when I switched to a formula that included it. The difference in energy quality was immediate — instead of the jittery, heart-pounding rush I was used to from straight caffeine, the energy felt smooth and focused. I could actually concentrate on my mind-muscle connection during sets instead of just feeling amped up. The second is citrulline at a full 6-gram dose or higher. I ran a personal experiment where I tracked my pump and vascularity on arm days with and without adequate citrulline. The difference was obvious enough that my training partner noticed without me saying anything.
Ingredients to Be Skeptical About
- Arginine: Often included for nitric oxide production, but it has poor oral bioavailability. Citrulline is a far superior choice since it actually converts to arginine more efficiently once absorbed.
- BCAAs (in pre-workout): If you’re already consuming adequate protein, added BCAAs provide no additional benefit for muscle building. They’re redundant in a pre-workout.
- Proprietary blends: Any product that hides individual ingredient doses behind a “proprietary blend” label is a red flag. This practice exists to mask under-dosing. Always choose products with transparent labels.
- Deer antler velvet, “matrix” complexes, “explosion” blends: Marketing terms with no meaningful clinical significance.
When should you take pre-workout?
For most pre-workout formulas, the optimal window is 20-30 minutes before training. This allows caffeine to reach peak blood concentration, which occurs approximately 30-60 minutes after ingestion.
If your pre-workout contains citrulline, taking it 30-45 minutes before training gives it time to boost nitric oxide levels. Beta-alanine and creatine are saturation-based and don’t require specific timing, but there’s no harm in taking them as part of your pre-workout routine.
Training Time Considerations
- Morning training: Full dose is fine — caffeine will be cleared well before bedtime
- Afternoon training (before 3-4 PM): Full dose for most people, but be aware of your caffeine sensitivity
- Evening training (after 5 PM): Consider a stimulant-free pre-workout. Caffeine has a half-life of 5-6 hours, meaning half the dose is still active that many hours later. A 300mg dose at 6 PM means ~150mg still circulating at midnight.
Side Effects and Safety
Pre-workout supplements are generally safe for healthy adults, but there are side effects to be aware of:
- Jitters and anxiety: Usually from excessive caffeine. Start with a half dose to assess tolerance. If you’re also drinking coffee, account for total daily caffeine.
- Tingling (paresthesia): Caused by beta-alanine. Harmless but can be intense at higher doses. Spreading beta-alanine intake across the day reduces this effect.
- Digestive discomfort: Some people experience nausea or stomach cramps, often from magnesium-based ingredients or taking pre-workout on a completely empty stomach. A light snack 30-60 minutes before can help.
- Elevated heart rate and blood pressure: Caffeine and other stimulants will raise both. If you have cardiovascular issues, consult your doctor before using stimulant-based pre-workouts.
- Sleep disruption: The most common and most underestimated side effect. Poor sleep from late caffeine intake will destroy your recovery and negate any performance benefit the pre-workout provided.
- Dependency: Regular use can create psychological dependency — the feeling that you can’t train hard without it. Periodically training without pre-workout helps maintain perspective.
Key finding: A 2018 systematic review in the British Journal of Sports Medicine found that caffeine has a half-life of approximately 5 hours, meaning a 300mg dose taken at 4 PM still leaves ~150mg active at 9 PM — enough to significantly disrupt sleep quality and recovery.
Who should skip pre-workout supplements?
Pre-workout isn’t for everyone. Consider avoiding it if you:
- Have high blood pressure or cardiovascular conditions
- Are sensitive to caffeine or experience anxiety
- Train in the evening and struggle with sleep
- Are under 18 (developing bodies don’t need stimulant supplements)
- Are pregnant or nursing
- Take medications that interact with stimulants (MAOIs, certain blood pressure drugs)
A strong cup of black coffee (100-200mg caffeine) with a banana is a perfectly effective, inexpensive pre-workout alternative for many people.
How to Read a Pre-Workout Label
Use this checklist to evaluate any pre-workout product:
- Transparent label? Every ingredient dose should be listed individually. No proprietary blends.
- Caffeine dose listed? Should be clearly stated. 150-300mg is the effective range for most men.
- Citrulline at 6g+? Anything less is likely under-dosed.
- Beta-alanine at 3.2g+? Clinical dose for carnosine loading.
- Third-party tested? Look for NSF Certified for Sport, Informed Sport, or USP verification for assurance against banned substances.
One mistake I made for years: taking a full scoop of a new pre-workout without testing half first. I switched to Gorilla Mode after using C4 for months, took a full serving with 350 milligrams of caffeine on top of my morning coffee, and my heart rate was sitting at 110 BPM before I even touched a barbell. I felt jittery, nauseous, and my workout was actually worse than if I had taken nothing. Now I always start with half a scoop of any new product, no exceptions. It takes one bad experience to learn that lesson.
The Practical Takeaway
A good pre-workout supplement can genuinely enhance your training — providing more energy, better endurance, stronger pumps, and sharper focus. But “good” means clinically dosed ingredients on a transparent label, not the flashiest packaging or most aggressive marketing.
Look for products built around caffeine (150-300mg), citrulline malate (6-8g), and beta-alanine (3.2g+) as the foundation. Everything else is secondary. Take it 20-30 minutes before training, avoid it within 6 hours of bedtime, and cycle off periodically to maintain caffeine sensitivity.
Most importantly, remember that a pre-workout supplement enhances a solid training program — it doesn’t replace one. No scoop of powder compensates for inconsistent training, poor nutrition, or inadequate sleep. Get the fundamentals right first, then optimize with the right pre-workout supplement for your needs.
