L-Proline Powder by Source Naturals Inc. 4 oz Powder L-Proline is an amino acid involved in the production of collagen and cartilage and may help support healthy joints and a healthy musculoskeletal system. L-Proline can be made in the body but low protein vegetarian diets may not always promote optimal production. Supplement Facts for Powder Serving Size 1 Teaspoon (approx. 2 g) Amount DV Calories 10 L-Proline 2 g Other Ingredients Suitable for vegetarians. Warning If you are pregnant may become pregnant or breastfeeding consult your health care professional before using this product. Do not use if either tamper-evident seal is broken or missing. Keep out of the reach of children. Suggested Use 1 to 2 level teaspoons daily mixed with water or juice.