When I hit 40 yr old, why did my energy drop so much? Should I spend some money to buy health supplements? If yes, what supplements are essential?

Quite normal lah, after 40, body slow down a bit. Could be sleep, stress, or diet issue. Supplements can help, but don’t overdo. Maybe just basics like multivitamin, omega-3, or vitamin D. Still, fix sleep, eat well, and exercise first, that’s the real energy booster.

Ginseng?