Norepinephrine isn’t a fuel — it’s a regulator
Norepinephrine is usually introduced as the “alertness” or “fight-or-flight” chemical. That is true but incomplete. Norepinephrine is better understood as a regulator — a signal that adjusts how other systems behave — and it has at least four jobs that matter for ME/CFS.
1. It sets arousal and sleep-state transitions. Noradrenergic neurons in the locus coeruleus are active during wakefulness and quiet during sleep, and their activity sets the substates of non-REM sleep (Osorio-Forero et al. (2021)). Noradrenergic “microarousals” also sit at the centre of restorative sleep function (Lüthi and Nedergaard (2025)).
2. It drives the pumping that clears the brain. During sleep, norepinephrine drives slow waves of blood-vessel movement (vasomotion) that are thought to push cerebrospinal fluid through the brain and clear metabolic waste — shown in mice and reviewed, not measured in ME/CFS (Hauglund et al. (2025); Nedergaard (2026)).
3. It gates pain. Descending pathways from the brainstem release norepinephrine in the spinal cord to damp pain signals (Hayashida and Obata (2019)), which is why noradrenergic drugs are used for chronic pain. In the ME/CFS CSF study, though, the norepinephrine pathway did not correlate with pain — so this role is established in other contexts, not demonstrated in ME/CFS (Aregawi et al. (2026)).
4. It helps supply fuel. Norepinephrine stimulates astrocytes — support cells — to break down glycogen and release lactate, the fuel neurons burn (Hertz et al. (2015); Killeen, Russell, and Sergeant (2013)).
Why this framing matters: if the problem is mainly a shortage of fuel, you treat it by adding fuel; if the problem is more a regulator, its failure shows up as disturbed sleep, poor clearance, and effort intolerance, and the fix may be different. A molecule can be both, so this is a matter of emphasis.
A caveat: this is a useful reframing, not proof. The added roles come from animal and general studies; they have not been measured in ME/CFS.