I'm 29 I gym 4 to 6 times per week for the pass 10 years, I need to take sum type of supplements to help maintain strength, size and for joint pain?

Natural health. If you have a healthy diet that replaces the protein, carbs, fats used during your workouts and normal activity, you do not need to take supplements. Older adults do lose muscle mass, but are still able to maintain healthy muscle definition by continuing to work out (even if with smaller weight) and eating a well-balanced diet. If you have food restrictions, you may need to look into supplements.
Balanced Diet. As long as you eat a well balanced diet you should be fine. If your joints are paining make you you stretch adequately pre and post workouts; and lighten your load in the gym. Glucosamin chondroitin is great for joint issues; but best to discuss this with your primary care doc to make sure it will fit with your overall health plan.