Every thought costs energy. Your cells pay with ATP – adenosine triphosphate. Spending it leaves ADP and AMP, which the mitochondria recharge or the cell breaks down further. One of the breakdown products, adenosine, builds up in the brain the longer you are awake. It is a key signal of sleep pressure – and sleep clears it again .
What about energy drips? Intravenous NAD+ and similar infusions are marketed as energy boosters. Robust trials showing benefits for mood or fatigue in healthy people are lacking. The order that works: fuel, sleep, movement – then targeted support where a real gap has been measured.
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Caffeine blocks adenosine receptors . The tiredness signal goes quiet, but the energy debt behind it remains – and adenosine keeps accumulating. The effect lasts hours, not minutes: in a controlled study, 400 mg of caffeine taken 6 hours before bed still cut total sleep by more than one hour . Use coffee as a tool in the first half of the day, not as a replacement for breakfast.
Creatine
A backup battery, not a fuel
Phosphocreatine recharges ADP to ATP within seconds – a buffer for tissues with spiky energy demand such as muscle and brain . In a randomised trial, women with major depression who added 5 g of creatine a day to their antidepressant improved faster than with placebo . A 2025 meta-analysis of 11 trials, however, found only a small average effect with very low certainty of evidence . The standard intake is 3–5 g per day . Promising as an add-on – not a treatment.