Caffeine Dosing for Strength and Power: 3-6 mg/kg and When to Take It

The caffeine dosage for strength that research supports is 3-6 mg per kg of body weight, taken about 60 minutes before you train. For a 70 kg lifter that works out to roughly 210-420 mg. Going higher does not reliably help and tends to bring jitters, a racing heart and wrecked sleep.

That is the short answer. This article is the practical version: how to turn mg/kg into a number you can actually swallow, when to take it, why more is not better, and how to handle evening sessions. (For how caffeine fits next to creatine and protein, see our complete guide to creatine, protein powders and caffeine.)

How much caffeine should you take before a workout?

Start with your body weight in kilograms and multiply by 3 and by 6. That is your studied range.

The International Society of Sports Nutrition (ISSN) position stand states that caffeine has consistently improved exercise performance at 3-6 mg/kg, that the minimal effective dose may be as low as 2 mg/kg, and that very high doses (such as 9 mg/kg) are linked to a high rate of side effects without seeming necessary (Guest et al., 2021). Note that the position stand’s authors disclose several ties to supplement companies, which is standard for this field but worth knowing.

Here is what that looks like on the scale.

Body weight	3 mg/kg	6 mg/kg
50 kg	150 mg	300 mg
60 kg	180 mg	360 mg
70 kg	210 mg	420 mg
80 kg	240 mg	480 mg
90 kg	270 mg	540 mg

Want your own number? Use the caffeine dosage calculator, which also caps the top of the range at 400 mg.

What does caffeine actually do for strength and power?

Less than the marketing suggests, but it is real.

A 2018 systematic review and meta-analysis of 10 strength studies and 10 power studies found caffeine improved both maximal strength (standardized mean difference, SMD, 0.20) and power measured by vertical jump (SMD 0.17) (Grgic et al., 2018). Subgroup analysis suggested the strength effect was clearer for upper body (SMD 0.21) than lower body (SMD 0.15, which was not statistically significant). The authors also asked for more data in women and for better control of blinding, because people often guess correctly whether they got caffeine.

An SMD of 0.2 is small. Think “a slightly better day,” not “a different lifter.”

More recent data point the same way for bar speed. A 2025 meta-analysis of 12 studies (230 participants) found caffeine improved mean bar velocity (SMD 0.42) and mean power output (SMD 0.21) during resistance exercise, with no significant difference across loads (Xiao et al., 2025). Heterogeneity for velocity was high, so the exact size is uncertain. Benefits were larger in males and in people who normally consumed less than 3 mg/kg of caffeine a day.

Why not take more than 6 mg/kg?

Because the extra benefit is unreliable and the cost is not.

In a randomized, double-blind crossover trial, 13 resistance-trained men did squat and bench press tests after placebo, 3, 6 or 9 mg/kg of caffeine. At light loads (25-50% of 1RM), all three doses increased bar velocity by roughly 5-8%. At 75% of 1RM, 3 mg/kg did not improve squat or bench power. Only 9 mg/kg improved bench velocity and squat power at 90% of 1RM, and 9 mg/kg also sharply increased side effects (15-62%) (Pallares et al., 2013).

So a case can be made for a higher dose when the load is very heavy. But that is one small trial of 13 men.

Then there is the opposite finding. A 2024 crossover trial in 16 female team-sport athletes (average age about 17) who were mild caffeine consumers compared the same three doses. Sprint, agility and repeated-sprint results were better at 6 and 9 mg/kg than at 3 mg/kg, with no significant difference between 6 and 9 mg/kg, and side effects were most frequent at 9 mg/kg. The authors recommended 6 mg/kg over 3 or 9 (Bougrine et al., 2024).

Why might the two trials differ? Different sexes and ages, different tests (heavy 1RM-percentage lifts versus sprints and jumps), different sample sizes, and different habitual caffeine intakes. Neither trial settles it.

A cautious takeaway: most lifters get the bulk of the benefit between 3 and 6 mg/kg. If your top set is a near-max single and you tolerate caffeine well, you could test the upper end of that range. There is little reason to go beyond it.

When should you take caffeine before lifting?

About 60 minutes before your first heavy set is a good default.

The ISSN position stand notes that 60 minutes pre-exercise is the most commonly used timing, and that the best timing likely depends on the source of caffeine. Gum, for example, may need a shorter wait (Guest et al., 2021).

A timing trial gives some support. In 29 resistance-trained people (18 men, 11 women), 6 mg/kg of caffeine was given 2 hours, 1 hour or 30 minutes before testing. Taking it 1 hour before gave the most consistent benefit, particularly compared with 2 hours, and the effects were more consistent in males than females (Harty et al., 2020). The study was small, so treat the exact windows as a guide.

Chewing gum is the exception. A 2026 meta-analysis of 21 studies found a small ergogenic effect of caffeinated gum on strength (SMD 0.21) and jump height (SMD 0.16) when it was chewed about 5-25 minutes before exercise, with no clear effect on muscular endurance (Varovic and Grgic, 2026).

In practice: if you train at 6 am in a rush, a capsule taken on waking will not hit its stride until you are well into your warm-up. Gum fills that gap. If you train after work, take your usual dose on the way to the gym.

Can you take caffeine before an evening workout?

Sometimes, but you pay for it in sleep if you overdo the dose.

A 2025 randomized crossover trial gave 23 young men placebo, 100 mg or 400 mg of caffeine 12, 8 or 4 hours before bedtime. The 100 mg dose had no significant effect on objective or subjective sleep, even 4 hours before bed. The 400 mg dose delayed sleep onset and changed sleep architecture within 12 hours of bedtime, caused more fragmentation within 8 hours, and reduced perceived sleep quality at 4 hours (Gardiner et al., 2025). The participants were all men with moderate habitual intake, so it may not apply to everyone, and the trial used flat doses rather than mg/kg.

Put plainly, you probably do not need 6 mg/kg for a 7 pm session. For late training:

• Aim for the low end of the range, or 2-3 mg/kg.
• Skip caffeine on lighter or technique-focused days.
• Notice how you sleep. People can misjudge how caffeine affects them, and the same trial showed that the objective and subjective picture did not always match.

Who should be careful with caffeine for lifting?

Anyone with a heart rhythm problem, uncontrolled high blood pressure, an anxiety disorder, or who is pregnant should speak to a doctor before using performance doses. Caffeine raises alertness and blood pressure and can trigger palpitations in sensitive people. Teenagers should not use performance doses without guidance from a doctor or qualified coach.

For context, the European Food Safety Authority considers habitual intakes up to 400 mg a day safe for healthy non-pregnant adults, and up to 200 mg a day in pregnancy. Heavier lifters whose 6 mg/kg figure passes 400 mg should treat 400 mg as a practical ceiling for the whole day, coffee and tea included.

Also stop and get medical advice if you get chest pain, palpitations that do not settle, fainting, or severe headaches after caffeine. This article is general information, not a diagnosis.

A simple protocol for your next heavy session

Keep it boring.

1. Work out 3 mg/kg for your weight and use that for 2-3 sessions.
2. Take it about 60 minutes before lifting (or gum about 5-25 minutes before).
3. Track your top-set weight and how fast the bar moves.
4. If it helps and you feel fine, move up toward 4-5 mg/kg. Do not exceed 6 mg/kg.
5. For evening sessions, drop to 2-3 mg/kg or skip it.

If tolerance is creeping in, our guide on caffeine tolerance and cycling covers how to reset. If caffeine makes you jittery, read pre-workout side effects and fixes. And if you want to know why one person feels wired on 100 mg and another feels nothing, see caffeine sensitivity and CYP1A2 genetics.

Dose depends on the form too: anhydrous versus natural caffeine affects how fast it peaks. For the broader picture of what is actually in a tub, see what clinical pre-workout doses look like and, for sleep, the afternoon caffeine cutoff.