Hydroxyproline, L-hydroxyproline, L-Proline, Proline Rich Peptides, Proline-Rich Polypeptides, PRPs, Pyrrolidine-2-carboxylic acid.


Overview Information

Proline is an amino acid, or a building block for protein. The body can make proline on its own, but it is also consumed in the diet. A typical diet contains about 5 grams of proline daily. The primary sources are protein-rich foods including meat, fish, and dairy. Proline can also be taken as a supplement.

Proline is used for skin healing, especially in people who have problems keeping enough proline in the body. It is also used for other conditions, but there is no good scientific evidence to support any of these uses.

In medicine, proline is used as a stabilizer to help some prescription products last longer.

How does it work?

The body uses proline to make proteins, such as collagen. Collagen is found in the skin, bones, and joints. Proline is also involved in the general function of cells.

Uses & Effectiveness?

Insufficient Evidence for

  • Athletic performance. Teens who eat more proline in the diet don't seem to be any more physically fit than teens who eat less proline.
  • Low bone mass (osteopenia). Eating more proline in the diet doesn't seem to protect against osteopenia.
  • Weak and brittle bones (osteoporosis). Eating more proline in the diet doesn't seem to protect against osteoporosis.
  • Fractures.
  • Fatigue.
  • Insomnia.
  • Infections.
  • Wrinkles.
  • Wound healing.
  • Skin ulcers.
  • Defects in proline metabolism.
More evidence is needed to rate the effectiveness of proline for these uses.
Side Effects

Side Effects & Safety

When taken by mouth: Proline is LIKELY SAFE when taken by mouth in food amounts. There isn't enough reliable information to know if proline is safe when used in larger amounts as medicine or what the side effects might be.

When applied to the skin: There isn't enough reliable information to know if proline is safe or what the side effects might be.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if proline is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to the amounts found in foods.

Children: Proline is LIKELY SAFE when taken by mouth in food amounts.



We currently have no information for PROLINE Interactions.



The appropriate dose of proline depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for proline. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

View References


  • Albaugh VL, Mukherjee K, Barbul A. Proline precursors and collagen synthesis: Biochemical challenges of nutrient supplementation and wound healing. J Nutr. 2017;147(11):2011-2017. View abstract.
  • Dunn R, Dolianitis C. Prolidase deficiency: the use of topical proline for treatment of leg ulcers. Australas J Dermatol. 2008;49(4):237-8. View abstract.
  • Dunstan RH, Sparkes DL, Macdonald MM, et al. Diverse characteristics of the urinary excretion of amino acids in humans and the use of amino acid supplementation to reduce fatigue and sub-health in adults. Nutr J. 2017;16(1):19. View abstract.
  • Gracia-Marco L, Bel-Serrat S, Cuenca-Garcia M, et al. Amino acids intake and physical fitness among adolescents. Amino Acids. 2017;49(6):1041-1052. View abstract.
  • Hagan JB, Wasserman RL, Baggish JS, et al. Safety of L-proline as a stabilizer for immunoglobulin products. Expert Rev Clin Immunol. 2012;8(2):169-78. View abstract.
  • Jamdar J, Rao B, Netke S, et al. Reduction in tibial shaft fracture healing time with essential nutrient supplementation containing ascorbic acid, lysine, and proline. J Altern Complement Med. 2004;10(6):915-6. View abstract.
  • Jemec GB, Moe AT. Topical treatment of skin ulcers in prolidase deficiency. Pediatr Dermatol. 1996;13(1):58-60. View abstract.
  • Jennings A, MacGregor A, Spector T, Cassidy A. Amino acid intakes are associated with bone mineral density and prevalence of low bone mass in women: Evidence from discordant monozygotic twins. J Bone Miner Res. 2016;31(2):326-35. View abstract.
  • Kawashima M, Yokose U, Hachiya A, et al. Improvement of crow's feet lines by topical application of 1-carbamimidoyl-L-proline (CLP). Eur J Dermatol. 2013;23(2):195-201. View abstract.
  • Nuttall FQ, Gannon MC, Jordan K. The metabolic response to ingestion of proline with and without glucose. Metabolism. 2004;53(2):241-6. View abstract.
  • Phang JM, Liu W, Zabirnyk O. Proline metabolism and microenvironmental stress. Annu Rev Nutr. 2010;30:441-63. View abstract.
  • Szoka L, Karna E, Hlebowicz-Sarat K, Karaszewski J, Palka JA. Exogenous proline stimulates type I collagen and HIF-1a expression and the process is attenuated by glutamine in human skin fibroblasts. Mol Cell Biochem. 2017;435(1-2):197-206. View abstract.

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CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty 2018.