The simple rule
Caffeine makes the most sense when your workout is early enough that it will not interfere with sleep. For many athletes, that means morning or early afternoon sessions.
Caffeine-free formulas are better for late training, second workouts, or days when you want pump, hydration, and performance support without extra stimulation.
Why timing matters
Caffeine can stay active for hours, so a strong pre-workout late in the day may make it harder to fall asleep or recover well. That is why Eclipse Hydration separates Sun and Moon into different routines.
Sun is built around morning energy. Moon is built around nighttime training support, hydration, and recovery without caffeine.
What to look for
A useful pre-workout should make the ingredient purpose obvious. Energy, pump, hydration, and recovery all serve different jobs. The best choice depends on when you train and what you need from the session.
If you train late, prioritize hydration, electrolytes, carbohydrates, and blood-flow support before reaching for another stimulant.