Short answer: ordinary caffeine intake does not automatically cause net dehydration in healthy, caffeine-habituated adults. But a pouch is not a beverage: unlike coffee or tea, it contributes virtually no drinking water, so users still need to hydrate normally.
Where the dehydration claim came from
Caffeine can increase urine output, especially at larger acute doses in people who have not used caffeine recently. A review found that typical beverage-size doses generally did not produce fluid loss beyond the fluid consumed with the beverage. A meta-analysis reported a small diuretic effect at rest that was reduced during exercise.
Why pouch context is different
Those studies largely concern swallowed caffeine and beverages, not guarana pouches. A pouch delivers caffeine without a cup of water. Therefore, “caffeinated drinks can count toward fluid intake” cannot be rewritten as “a caffeine pouch hydrates.” Direct finished-pouch hydration studies are lacking.
Dose still drives the discussion
A formula using 20% guarana extract theoretically supplies 40 mg caffeine from 200 mg extract or 60 mg from 300 mg. Multiple pouches plus coffee or pre-workout can move total exposure into a different range. Heat, exercise, illness and alcohol also change hydration needs.
Practical signs and habits
Drink according to thirst and the conditions rather than using caffeine as a hydration cue. During long exercise or heat exposure, follow an appropriate fluid and electrolyte plan. Dark urine, dizziness, unusual fatigue or reduced urination can have several causes and should not be self-diagnosed as “just caffeine.”
A precise marketing answer
It is reasonable to say that caffeine has a mild, context-dependent diuretic effect. It is not reasonable to promise that a guarana pouch cannot contribute to hydration problems in every user or situation. The defensible advice is to disclose caffeine clearly and remind users that pouches do not replace fluids.
Sources
Frequently asked questions
Do caffeine pouches make you pee more?
Caffeine can modestly increase urine output, particularly at larger doses and in non-habituated users, but the response varies.
Does a guarana pouch count toward water intake?
No. A pouch supplies no meaningful drinking water, so normal fluid intake is still required.
Should I drink water with a caffeine pouch?
Maintain appropriate hydration for your activity, climate and health; do not treat the pouch as a fluid source.