The Bottom Line
- Don’t experiment in exam week. Run a ‘trial’ caffeine plan in training weeks.
- Caffeine can improve alertness but can also impair sleep — sleep loss harms memory.
- Avoid high-dose supplements; treat caffeine like a controlled tool.
Safety anchor (adults)
UK and European safety guidance commonly references that daily caffeine intakes up to ~400mg in healthy adults are unlikely to cause adverse effects, with lower limits advised in pregnancy and for those sensitive to caffeine.
The exam-week mistake
New caffeine routines (or high-dose caffeinated supplements) during exam week are a common self-sabotage: jitteriness, anxiety, and sleep disruption. Practise your routine weeks in advance so you know your response.
1
Step 1 — Choose your ‘minimum effective dose’
Start smaller than you think. The goal is alertness without tremor/anxiety. If you need ever-increasing doses, your sleep and baseline fatigue are the real problems.
2
Step 2 — Time it to protect sleep
Set a caffeine cut-off that preserves sleep onset and quality. If your sleep suffers, your long-term retention and next-day performance typically suffer too.
3
Step 3 — Build an exam-day plan you’ve rehearsed
Use the same dose and timing you used in practice mocks. Add water + food. Avoid stacking energy drinks and unknown supplements.
1
2
3
4
SourceUK Food Standards Agency — caffeine guidance (incl. 400mg/day reference)
Open Link SourceEFSA — caffeine safety overview (incl. 400mg/day reference)
Open Link