Finnegan's on Omega Alpha GlucosaPet as a preventative. Look for natural supplements with glucosamine, chondroitin and MSM.
If you're not sure what it all does: Glucosamine sulfate can help rebuild joint cartilage and prevent further loss of it, chondroitin is used in conjunction with MSM for anti-inflammatory properties, and some studies show MSM is also an effective pain reliever.
Can you get NaturVet pet supplements near you? Our customer dogs have had amazing results on their joint formulas, they're all natural, and they guarantee their products 100%. I like the joint formulas because they're time-release tablets.
Their Arthrisoothe (Stage 3 joint formula) is the best for older dogs starting to show more severe movement limitations. I like that it also includes a small dosage of Hyaluronic Acid, which has shown in some studies to be even better for cartilage than glucosamine. I've seen some very senior, slow dogs get a LOT of their freedom of movement back using this or similar joint formulas. This is their ingredient panel and amounts (I've bolded the most important ones, though the extra herbals help as well), so maybe you can find something similar if not the same:
Glucosamine HCI (Shellfish Source) - 500 mg
Methylsulfonylmethane (MSM) - 500 mg
Chondroitin Sulfate (Bovine Source) - 200 mg
Green Lipped Mussel (Perna Canaliculus) - 200 mg
Boswellia Serrata - 90 mg
Yucca Schidigera - 90 mg
Vitamin C (Calcium Ascorbate) - 60 mg
Type II Collagen (from Kolla2) - 32 mg
Zinc - 7 mg
Hyaluronic Acid (from Kolla2) - 5 mg
dl-Alpha Tocopheryl (Vitamin E) - 60 IU