That fish oil comes from fish is no surprise, but the other animal-derived ingredients hidden in supplements can be hard to detect. Check out these vegetarian alternatives to traditional ingredients.

Vegetarian option: Borage and evening-primrose oils; vegetarian DHA

What they do: Natural oils reduce inflammation; DHA harvested from algae balances hormones and nourishes the brain.

Dose: 360 mg oil daily, divided; 120 mg DHA daily

What they replace: Fish oil.

Vegetarian option: Methylsulfonylmethane (MSM)

What it does: Sulfur compounds from green plants and algae stimulate cartilage growth and mitigate joint pain.

Dose: 1-3 grams daily

What it replaces: Glucosamine sulfate made from shrimp, lobster, and crab shells.

Vegetarian option: Modified vegetable cellulose capsules

What they do: Smooth casings made from structural plant fibers make pills easy to swallow.

What they replace: Gelatin capsules made from cow-bone collagen.

Vegetarian option: Red yeast rice

What it does: Monacolin compounds may reduce LDL (bad) cholesterol.

Dose: 2,400 mg daily

What it replaces: Chitosan from shrimp and crab shells.