Cooling products for hot flashes: what works and what is marketing

What cooling can and cannot do

Hot flashes happen because the thermoneutral zone has narrowed, so small rises in core temperature cross a threshold. Cooling does not widen that zone. It keeps you further from the edge of it.

That distinction sets realistic expectations: cooling reduces how often you cross the threshold and makes crossing it more bearable. It does not stop the mechanism, and a product claiming to do so is overstating.

Where the body actually loses heat

Glabrous skin — the hairless skin of the palms, soles and face — contains specialised blood vessels called arteriovenous anastomoses that act as radiators, allowing large volumes of blood to be cooled quickly.

This is why holding something cold in the hands, or putting the feet out of the bedcovers, is disproportionately effective compared with cooling the torso. It is also the physiological basis for cooling devices used by athletes.

Practically: a cold drink held in the hands, running wrists under cold water, or keeping feet uncovered at night are low-cost interventions grounded in how heat exchange actually works.

What helps at night

• A cool room, which the evidence favours over heavy bedding kicked off during a flash
• Layered bedding rather than one duvet, so the amount can be adjusted without fully uncovering
• Natural or moisture-wicking nightwear, which reduces the chill phase by not holding sweat against skin
• A spare set of nightwear within reach, so a night sweat does not require becoming fully awake
• A fan, which works by increasing evaporative loss and is more effective on exposed skin than through bedding
• Cooling pillow inserts and mattress toppers, which have a reasonable physical basis but little trial evidence

What the evidence does not support

There is very little randomised trial evidence for cooling products specifically, which is worth stating plainly in a market this large. The rationale is physiological rather than demonstrated.

Claims that a garment, spray or supplement reduces hot flash frequency should be treated sceptically, particularly given that the placebo response for hot flashes in trials is consistently large — large enough that almost anything produces convincing personal accounts of improvement.

Cooling is a comfort measure. Where flashes are frequent enough to disrupt sleep or work, it is worth having the treatment conversation as well rather than instead.

When to see someone

If you are managing with cooling alone because you believe there are no other options, it is worth knowing that both hormonal and non-hormonal prescription treatments exist, including for women who cannot take hormones.

See someone for flushing accompanied by weight loss, diarrhoea or palpitations, and for drenching night sweats with fever or a persistent cough, which belong to a different category.