IngredientStudied forEvidence in shortUsual form
Boswellia serrata Joint comfort, stiffness and function in short trials Small short trials and a meta-analysis of 7 studies show improvement vs placebo; larger studies needed Capsule, tablet
Chondroitin sulfate Joint comfort Cochrane review: small short-term benefit; better-quality trials show weaker or no effect Tablet, capsule, powder stick
Eggshell membrane Knee joint comfort and stiffness Small trials mostly positive, one showed no group difference; industry-funded; egg allergen Capsule
Glucosamine Joint comfort and mobility Large trials and meta-analyses show weak or mixed results overall Tablet, capsule, powder stick
MSM (methylsulfonylmethane) Knee joint comfort and physical function Small trials mixed; one negative at 3 g a day, others positive at other doses Tablet, powder
Proteoglycan (salmon nasal cartilage) Everyday knee comfort; skin moisture Small Japanese trials only; overall group differences were mixed Capsule, tablet, powder, drink
Undenatured type II collagen Knee joint flexibility and comfort during activity Several small trials positive for knee comfort; most industry-funded Capsule, tablet