Chondrointin in conjunction with those and good diet.
A massively underrated aspect of joint health is technique and correct muscle balance causing tension across the joints to be correct. Humans were not created to move on man-made, consistent (every step is the same) surfaces. This is why tracks and treadmills have even more injuries than road or sidewalk---despite being soft.
If people want to protect their joints, they should eat healthy and seek out uneven terrain (grass, cobblestones, dirt trails, etc.) as much as possible. The more uneven the terrain is and the more it makes your hips tilt, the better it is for your joints. According to research I did at BYU, people need to get 1/3 of their terrain on natural or uneven terrain for the most protective benefit.