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Overview: Proline is an amino acid that your body uses for many important functions, including building proteins. Your body makes proline on its own, and you can also get it from your diet. Proline dietary supplements appear to be well tolerated. However, since your body makes this amino acid on its own, it is not clear if these supplements offer any benefits. Before taking proline, tell your health care provider about all of your health conditions and any medicines or supplements you may be using.

Uses

What is proline used for?

Proline supplements are used to increase energy levels and improve joint and skin health. However, their benefits for any use are not well defined.

Note: The FDA has not reviewed proline for safety and effectiveness. Learn more about dietary supplements here.

How does proline work (mechanism of action)?

Proline is an amino acid, which is a building block of protein. The cells in your body use proline to send signals and to make another amino acid called hydroxyproline. Your body makes proline from glycine, which is another common amino acid. It is also found in the diet, including in meat, fish, dairy products, nuts, seeds, and soy.

Your body usually makes enough proline to meet your needs. However, during severe illnesses or injuries, your body may need more proline than it can make on its own. In these cases, your body can use the proline found in foods. It is not clear if taking proline supplements can improve health or recovery from serious illnesses or injuries.

Proline and hydroxyproline are both building blocks for collagen, a protein that is important for the structure and health of your joints, tendons, ligaments, bones, and skin. Some people take proline supplements to improve joint and skin health. But it is not clear if proline supplements can increase collagen levels in the body. Their benefits for any use are not well defined.

How should I store proline?

You should store proline according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of proline?

Proline seems to be well tolerated. Tell your health care provider if you have any side effects that bother you.

There may be side effects of proline that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of proline?

While less common, the most serious side effects of proline are described below, along with what to do if they happen.

Severe Allergic Reactions. Proline may cause allergic reactions, which can be serious. Stop taking proline and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use proline?

Allergies to Ingredients. People who are allergic to any of the following should not take proline.

  • L-proline
  • Proline
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific proline products they stock.

What should I know about proline before using it?

Proline is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep proline out of the reach of children.

If you are taking proline powder, use an accurate measuring device to measure the powder, such as the device included with the product. Read the label carefully and measure the amount stated on the label.

The FDA has not tested proline products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using proline?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. Also tell them if you have an upcoming surgery planned. Sharing this information will help your health care provider know if this or other supplements are right for you.

In particular, make sure that you discuss any of the following.

Cancer. If you currently have cancer or have a history of cancer, speak with your health care provider before taking proline.

Pregnancy. It is not known if or how proline could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Proline is a natural part of breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does proline interact with foods or drinks?

There are no known interactions between proline and foods or drinks.

It is unknown if drinking alcohol will affect proline. 

Does proline interact with medicines (drug interactions)?

There are no known interactions between proline and medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

The interactions between proline and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with proline is incomplete. Always check with your health care provider before taking proline with any medicines.

Overdose/Missed Dose

What should I do if I accidentally use too much proline?

If you or someone else has used too much proline, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Read the product label closely and speak with a health care provider about how to take proline safely. Do not take double or extra doses, even if you miss a dose.