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Overview: Histidine is an amino acid that is naturally found in various plant- and animal-based foods. Your body is not able to make histidine on its own, but most people get enough histidine from their diets. Dietary supplements containing histidine seem to be well tolerated, but their benefits for any use are not well defined. Before taking histidine, make sure to tell your health care provider about any medicines you are taking or health conditions you have, including allergic conditions.

Uses

What is histidine used for?

Histidine supplements are used for various reasons, but their benefits are not well defined. Some common reasons for using histidine include the following.

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

How does histidine work (mechanism of action)?

Histidine is an amino acid, which is a building block of protein. Your body is not able to make histidine on its own, so you must get it from the foods in your diet. Protein-rich foods contain histidine, including meat, fish, and eggs. It is also found in plant-based proteins, such as whole grains, beans, and nuts. Your body uses histidine to build proteins and to make another chemical called histamine.

Most people know of histamine because of its involvement in allergic reactions. When your immune system senses an allergen, it releases histamine, which in turn tells your body to produce an allergic reaction.

Histamine also plays an important role in your brain, where it sends some of the signals that your brain cells use to communicate. Histidine supplements are sometimes used to improve brain health and increase energy levels. But there is no good evidence that these supplements provide any benefits.

Some research has found that low levels of histidine in the body may be connected to certain skin problems, such as eczema. This has led to interest in taking histidine supplements to improve skin health. But there is not enough research to know whether these supplements are helpful. Most people get enough histidine from their diets.

How should I store histidine?

You should store histidine 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 histidine?

Histidine 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 histidine 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 histidine?

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

Severe Allergic Reactions. Histidine may cause allergic reactions, which can be serious. Stop taking histidine 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 histidine?

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

  • Histidine
  • L-histidine
  • Any of the ingredients in the specific product

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

What should I know about histidine before using it?

Histidine 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 histidine out of the reach of children.

The FDA has not tested histidine 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 histidine?

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.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Kidney problems
  • Liver problems

Allergic Conditions. Histidine supplements may increase the risk of allergic reactions in people who have a history of allergic reactions (atopy) or who have allergic conditions such as asthma or eczema. This risk is not well understood. Talk to your health care provider if you have any of these conditions before taking histidine supplements.

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

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

Interactions

Does histidine interact with foods or drinks?

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

It is unknown if drinking alcohol will affect histidine.

Does histidine interact with medicines (drug interactions)?

There are no known interactions between histidine 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 histidine and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with histidine is incomplete. Always check with your health care provider before taking histidine with any medicines.

Overdose/Missed Dose

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

If you or someone else has used too much histidine, 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 histidine safely. Do not take double or extra doses, even if you miss a dose.