Caffeine

All Supplements

Evidence summary

Caffeine has very strong evidence in this guide. The reference dose is 100-400mg, with timing listed as 30-60 minutes before training. Supplements should support a sound diet and training plan, not replace them.

• Increased alertness and focus
• Enhanced endurance performance

What Is Caffeine?

Caffeine is a natural stimulant found in coffee, tea, cocoa, and many sports supplements. It is the most widely consumed psychoactive substance in the world and one of the most well-researched ergogenic aids in sports science. Whether you get it from a cup of coffee or a caffeine tablet, the performance benefits are real and well-documented.

How It Works

Caffeine works primarily by blocking adenosine receptors in your brain. Adenosine is a neurotransmitter that builds up throughout the day and makes you feel tired. By blocking it, caffeine keeps you alert and reduces the perception of effort during exercise. It also stimulates adrenaline release and may increase fat oxidation during endurance activities.

The Half-Life Problem

Caffeine has a half-life of approximately 5 hours — meaning if you consume 200mg at 4pm, you still have roughly 100mg in your system at 9pm. This is why timing matters. If you train in the evening, consider lower doses or caffeine-free alternatives to protect your sleep. Poor sleep undermines recovery far more than caffeine improves performance.

What the Research Says

Caffeine is one of the few supplements with unanimous support from sports science. Meta-analyses show it improves endurance performance by 2-4%, increases strength and power output, enhances focus, and reduces perceived exertion. The effective dose for performance is typically 3-6mg per kg of bodyweight, though many people benefit from lower amounts.

Tolerance and Cycling

Your body adapts to caffeine over time, reducing its stimulatory effects. If you find your morning coffee no longer wakes you up, your tolerance is high. Consider cycling off caffeine for 7-14 days every couple of months to reset sensitivity. Expect withdrawal headaches for the first 2-3 days — they pass quickly.

Coffee Counts

You do not need caffeine tablets or pre-workout to get the benefits. A standard cup of coffee contains roughly 80-100mg of caffeine. Two cups before training puts you in the effective range for most people. Caffeine tablets simply offer more precise dosing and zero calories.

Who Should Take It

Anyone looking for a safe, cheap, and proven performance boost. It is particularly effective for early-morning sessions, endurance training, and high-volume lifting days. Start with a lower dose (100-150mg) to assess your tolerance.

Who Should Avoid It

People with anxiety disorders, heart arrhythmias, or high blood pressure should be cautious. Pregnant individuals should limit intake to under 200mg daily. If you are caffeine-sensitive, even small doses may cause jitters — listen to your body.

Vegan?

Caffeine is vegan-friendly. Whether sourced naturally from plants or produced synthetically, it contains no animal products. Coffee, tea, and caffeine supplements are all suitable for vegans.

Where to Buy

• Myprotein Caffeine Tablets — from £4.99
• Bulk Caffeine Capsules — from £3.99
• Amazon — ProPlus Caffeine Tablets — from £3.49

Caffeine: common questions

What is caffeine used for?

Caffeine is commonly considered for increased alertness and focus, enhanced endurance performance, improved strength output, reduces perceived exertion, cheap and widely available. The evidence rating in this guide is very strong.

When should I take caffeine?

The practical timing used in this guide is 30-60 minutes before training. Consistency and the total daily dose are often more important than a narrow timing window.

How much caffeine should I take?

The reference dosage in this guide is 100-400mg. Individual needs vary, so check the product label and speak to a qualified healthcare professional if you have a medical condition, take medication, are pregnant, or are unsure.

Is caffeine vegan friendly?

This form of caffeine can be vegan friendly, but check the capsule, flavouring, and manufacturing details on the specific product.

Shop smarter

Supplement picks

Products that fit this supplement guide. Swap in tracked affiliate URLs once your accounts are approved.

Popular pre-workout

Applied Nutrition ABE Pre-Workout

Lifters who want a caffeinated pre-workout with a familiar UK retail footprint.

Merchant

Amazon UK

Around £20-£28

Price checked 5 Jul 2026

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