Caffeine sensitivity is different from a caffeine allergy, which is rare and involves an immune response. Sensitivity instead relates to how the body metabolises caffeine, with differences linked to individual biology.
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Caffeine continues to be the world’s most widely used stimulant, found in coffee, tea, chocolate, energy drinks and some medications. However, experts say its effects vary widely from person to person, leading some consumers to experience side effects such as jitters, headaches, anxiety and sleep disruption.
Caffeine sensitivity is different from a caffeine allergy, which is rare and involves an immune response. Sensitivity instead relates to how the body metabolises caffeine, with differences linked to individual biology.
Research shows around 40% of people are fast metabolisers, breaking down caffeine quickly, while about 50% are intermediate metabolisers. The remaining 10% are slow metabolisers, meaning caffeine stays in their system longer and may trigger stronger effects such as restlessness, nausea or insomnia.
Because caffeine affects the central nervous system, its impact on physical and mental wellbeing can vary significantly. Sensitivity may also increase during perimenopause and menopause due to hormonal changes, with studies cited by the Mayo Clinic linking caffeine intake to worsened symptoms such as hot flushes and night sweats. Age-related changes can also slow metabolism and affect sleep quality, increasing sensitivity further.
The timing of caffeine intake is also gaining attention, particularly in relation to sleep. “Caffeine blocks adenosine, a chemical that helps the body wind down for sleep, keeping the brain alert when it should be preparing for rest,” explains Adele du Toit.
She adds that greater awareness is driving behaviour change, with many consumers opting for caffeinated drinks earlier in the day and switching to caffeine-free alternatives later on.
Global beverage trend research from Euromonitor International and Mintel shows growing demand for herbal and caffeine-free teas, driven in part by interest in relaxation and improved sleep.
Du Toit notes that many people underestimate their total caffeine intake due to its presence in a wide range of products. She says small adjustments, such as avoiding caffeine later in the day, can make a meaningful difference.
Health authorities generally consider up to 400 mg of caffeine per day safe for most adults, though tolerance varies individually.
The shift has also contributed to the rise of evening wellness rituals, with caffeine-free options such as rooibos becoming popular substitutes for late-day drinks. South African Rooibos Council highlights rooibos as a naturally caffeine-free option increasingly used to support evening relaxation routines.
Some emerging research has explored rooibos’ potential role in stress response, including possible effects on cortisol regulation, although individual experiences differ.
Experts say the trend reflects a broader focus on sleep health, as poor sleep is linked to reduced cognitive performance, higher stress and long-term health risks. As a result, reducing caffeine intake later in the day is increasingly seen as a simple step toward better sleep.
Du Toit says the shift is less about eliminating caffeine entirely and more about balance, with consumers becoming more intentional about when they consume it and how they unwind in the evening.
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