Does the Omius headband really reduce the body temperature of Olympic athletes?

What is it, and how does it work? Fans of athletics, especially running, may have raised this question when they noticed something unusual at the 2024 Olympic marathon: several runners, including champion Eliud Kipchoge, were seen wearing strange-looking headbands.
These headbands, it turns out, are cooling devices. According to the Omius website, the cooling effect comes from water being absorbed by special elements (“graphite cubes” – Behind the News), which provide a surface area five times larger than normal for evaporation.
“As the water transforms from liquid to gas, it evaporates from the graphite, drawing heat away from the cooling parts in contact with the skin, lowering the skin’s temperature. Since the effect is caused solely by water evaporation, this cooling effect can last indefinitely as long as air continues to circulate,” the company’s website explains.
In fact, the concept works similarly to a car radiator. It’s a design developed by Gustavo Cadena, who began working on the product in 2013. The headband is priced at around $200.
But how effective is it in practice?
While the technology sounds promising, there is limited scientific data to back it up. We discovered one small study, conducted in August 2024 with just 10 participants, which attempted to assess the product’s effectiveness. Therefore, its results should be interpreted with caution.
The athletes wore the headbands during “a 70-minute submaximal run (when the heart rate reaches high levels for a specific age and gender – Behind the News), followed by a five-kilometre time trial in hot and humid conditions.”
The study’s findings suggest that the Omius headband does slightly lower forehead temperature, according to subjective feedback from the athletes (the participants were not blinded).
However, there was no significant difference in objective measures between the group wearing the Omius headband and those wearing a sham version.
”The “high-tech” headband did not lower core body temperature (as measured by the rectal method), did not affect heart rate, and did not improve performance in the 5-kilometre race. Essentially, the expensive “high-tech” cooling headband and its imitation had the same overall effect