This study examined the effect of sustained-release caffeine capsules (SR-Caffeine) on memory, motivation, concentration, and attention, as well as the pharmacokinetic profile of the SR-Caffeine capsules.

Around the world, caffeine is one of the most widely ingested psychoactive ingredients/psychostimulants. It is found in beverages (coffee, tea, soda, and energy drinks), foods (chocolate and desserts), and drugs. 

Several factors affect how much caffeine adults consume, such as age, sex, social environment, nutrition, personality, culture, and habituation. However, approximately 80%–90% of adults consume caffeine daily, averaging 200–250 mg.

Several reasons for its popularity include its beneficial effects on mood, physiological, psychomotor, and cognitive functioning and its perceived immediate benefits.

It is believed that sustained-release (SR) formulations allow caffeine to be released at a controlled rate for extended periods, thus helping achieve a steady state of effective plasma concentration. This approach appears promising because it eliminates the need for repeated caffeine consumption, reducing the negative effects of caffeine crashes.

Additionally, the SR formulation reduces the amount of local and systemic side effects, reduces the fluctuations in circulating levels of active constituents, and increases compliance. CaffXtend® capsules contain long-acting beadlets containing 200 mg of natural caffeine, a novel SR formulation of caffeine.


The six-way crossover study was an open-label, randomized, single-dose, two-treatment, two-sequence, two-period, controlled trial wherein 15 healthy subjects were randomized (1:1) to receive SR-Caffeine (200 mg) or IR-Caffeine (200 mg).

In this study, blood samples were collected at various times. The primary outcome was to compare the relative bioavailability of SR-Caffeine 200 mg and IR-Caffeine 200 mg under fasting conditions. Additionally, caffeine research visual analogue scales (Caff-VAS) scores were assessed for relaxation, alertness, jitteriness, fatigue, tension, headache, overall mood, and mental fatigue.

However, overall exposure to SR-Caffeine and IR-Caffeine was similar. Caff-VAS results showed that the SR-Caffeine group scored significantly better for jitteriness, tiredness, alertness, and overall mood than the IR-Caffeine group for 8–12 hours.

No adverse events were reported. A significant improvement was observed in the scores for ”relaxed,” ”alertness,” and ”overall mood” from SR-Caffeine compared to IR-Caffeine after sustained caffeine release over 24 h. There was a significant reduction in scores for ”jittery” and ”tired” for extended periods of time.

Results of the Study

This study showed long and sustained caffeine release from SR-Caffeine, which took significantly longer to reach maximum concentration and had a longer half-life than IR-Caffeine. SR-Caffeine, which induced sustained plasma levels of caffeine for 8 to 12 hours, improves alertness and mood for longer.

In this study, SR-Caffeine was found to be safe and well tolerated. Hence, experts assume that a single daily dose of SR-Caffeine could provide an effective alternative to repeated daily doses of caffeine needed for sustained stimulant effects without causing a ”caffeine crash.”

To further validate the role of caffeine on cognitive performance and mental alertness and to evaluate whether the sustained release of caffeine will improve stimulation on long-term administration despite its tendency to induce strong habituation, long-term studies are necessary.

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