7 best pre-workout ingredients backed by science
Most pre-workout tubs hide a handful of proven ingredients behind a long list of filler. Once you know which ones earn their place, you can read any label in ten seconds and tell whether it's worth your money.
Here are the 7 best pre-workout ingredients backed by science, with the dose the research points to and what each one actually does. Use it as a checklist next time you're comparing products.
1. Caffeine
The most reliable performance ingredient there is. Caffeine improves endurance, raises power output, and lowers how hard a given effort feels, which is why it shows up in almost every serious formula.
Dose: 3 to 6mg per kilogram of bodyweight, around 45 to 60 minutes before you train (ISSN position stand, Guest et al., 2021). For a 75kg athlete that's roughly 225 to 450mg. Start low if you're sensitive. Our guide on caffeine timing covers when to take it for training versus racing.
2. Dietary nitrate (beetroot)
Nitrate from beetroot raises nitric oxide, which improves blood flow and makes your muscles use oxygen more efficiently. The effect is strongest for endurance and repeated high-intensity work, which describes Hyrox almost exactly.
Dose: roughly 300 to 600mg of nitrate (about 5 to 9mmol), taken 2 to 3 hours before you start, since it works on a slower clock than caffeine (nitrate and performance research, PubMed). We broke down the evidence in beetroot extract for endurance.
3. Citrulline
L-citrulline supports nitric oxide production and can reduce muscle soreness and the feeling of fatigue during training. It's the ingredient behind the "pump," but the useful part for athletes is the work-capacity angle, not the look.
Dose: studies tend to use 6 to 8g of citrulline malate before training (citrulline research, PubMed). Watch for products that include it at a token dose just to list it on the label.
4. Creatine
Creatine is the most researched supplement in sport. It supports the energy system you lean on for short, hard efforts, and it's a strong fit for the sleds, burpees, and wall balls in a Hyrox.
Dose: 3 to 5g per day, taken consistently, with no need to load (ISSN position stand, Kreider et al., 2017). It works through daily saturation rather than a pre-workout hit, so timing matters less than consistency. More detail in creatine for Hyrox.
5. Beta-alanine
Beta-alanine buffers the acid that builds up during hard efforts, which helps most in the 1 to 4 minute range where Hyrox stations live. The tingling skin sensation it causes is harmless, though some people find it off-putting.
Dose: 4 to 6g per day, taken consistently over weeks rather than as a single pre-workout dose (ISSN position stand, Trexler et al., 2015). We covered the event-specific case in beta-alanine for Hyrox.
6. L-theanine
L-theanine is an amino acid that takes the edge off caffeine. Paired with it, you get the focus and alertness without as much of the jitter and anxiety, which is why the two are often dosed together.
Dose: commonly 100 to 200mg alongside caffeine, often at roughly a 1:1 to 2:1 ratio of theanine to caffeine. If a pre-workout leaves you wired and anxious, a formula with theanine is worth trying.
7. Sodium and electrolytes
Easy to overlook in a pre-workout conversation, but starting a session topped up with sodium helps you hold pace and avoid cramps, especially in long or hot efforts. Sodium is the electrolyte you lose in performance-relevant amounts.
Dose: aim for 300 to 700mg of sodium per serving around training, scaled up if you're a heavy sweater (ACSM position stand, Sawka et al., 2007). See best electrolytes for Hyrox for how to choose one.
How to read a pre-workout label in 10 seconds
Flip to the ingredients panel and look for the actives above, each with a number next to it. A good label tells you exactly how many milligrams or grams of caffeine, citrulline, and the rest you're getting per serving.
If the doses are listed and they land in the ranges above, the product is doing its job. If the key ingredients are buried inside a single "blend" figure, you can't tell whether you're getting a clinical dose or a sprinkle, and the safe assumption is a sprinkle. Price per serving, not price per tub, is the honest way to compare once you've checked the doses.
What to skip
Proprietary blends that hide individual doses, mega-dose stimulant stacks built for a short-term buzz, and the long tail of unproven "performance" actives rarely justify the cost. If a label won't tell you how much of each ingredient you're getting, assume the doses are too low to matter.
How Interval approaches it
We built Pre-Shot around the proven actives at sensible doses, ready to drink, with no artificial sweeteners and no itch or crash. It's £9.99 for a 6-pack. Whatever you choose, ours included, run it against this list: clear doses, evidence behind each ingredient, and nothing hidden in a blend.
Common questions
What is the most important pre-workout ingredient? Caffeine, by a distance. It has the deepest evidence base and the most consistent effect on performance.
Which ingredients need daily use rather than a single dose? Creatine and beta-alanine both work through saturation over time, so take them every day rather than only before training.
Are natural pre-workout ingredients better? The source matters less than the dose and the evidence. Caffeine, nitrate, citrulline, creatine, and beta-alanine are all well studied at the doses above.
Keep the list short and the doses honest. Five proven ingredients at the right amounts beat a tub with twenty names and not enough of any of them.