My husband, who has sleep apnea, uses 5-hour energy to help him stay awake during the day. Will Customs confiscate his 5-hour energy bottles if packed loose inside his luggage? Should he leave the bottles inside the sealed box?
Check the Customs website, but even a "sealed" box won't protect larger than 4 oz bottles if they challenge you. Only they can say if it is or is not a "medicine" for which there may be greater allowances.
Why would you think they would be confiscated? This is not considered a medication, so would be subject to the regular liquids restriction for carry on luggage.
Energy drinks like Red Bull and their local brands are sold over there, so I doubt you’d have any problem. I’m sure a local will have an definitive answer.
To clarify, if he means to take them in his carryon, then it's a security issue, not a Customs issue. Follow the TSA rules for liquids.
Checked bag or carry on bag?
Each bottle looks to be ~2.oz.
If in your carry on then its a matter of how many fit in the quart bag.
Check your luggage and there shouldn’t be any problem.