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Overview: Sulforaphane is made from glucoraphanin, a chemical naturally found in cruciferous vegetables such as broccoli. When these vegetables are chopped or chewed, glucoraphanin is turned into sulforaphane. There is interest in using sulforaphane for many reasons, but its benefits are not well defined. Although it seems to be well tolerated, there is not enough research to know what side effects it may cause. Before taking sulforaphane, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is sulforaphane used for?

Sulforaphane is used for various reasons, although its benefits are not well defined. Some common reasons for using sulforaphane include the following.

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

How does sulforaphane work (mechanism of action)?

Sulforaphane is a chemical that comes from cruciferous vegetables such as broccoli, broccoli sprouts, kale, cauliflower, and broccolini. But these vegetables do not actually contain sulforaphane. Instead, sulforaphane is formed when these vegetables are chewed, chopped, or otherwise “damaged.” When the vegetable is damaged, a chemical called glucoraphanin mixes with an enzyme called myrosinase and forms sulforaphane.

Some research suggests that sulforaphane may have effects in the body, including acting as an antioxidant and reducing swelling (inflammation). In the laboratory, it also seems to help kill cancer cells, leading to interest in using it for cancer prevention. But research on sulforaphane for cancer is limited, and its benefits are not well defined or understood.

Sulforaphane is also sometimes used for certain neurological conditions, including autism and schizophrenia. Although some studies show that sulforaphane may help with certain symptoms, not all studies have shown benefit. Also, most of the benefits have been very small, so they may not be considered meaningful to most people. More research is needed to better understand whether sulforaphane is helpful for any neurological conditions.

How should I store sulforaphane?

You should store sulforaphane 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 sulforaphane?

Sulforaphane seems to be well tolerated. But there is not enough research to know what the common side effects may be. Tell your health care provider if you have any side effects that bother you.

There may be side effects of sulforaphane 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 sulforaphane?

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

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

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

  • Glucoraphanin
  • Sulforaphane (SFN)
  • Sulforaphane glucosinolate
  • Any of the ingredients in the specific product

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

What should I know about sulforaphane before using it?

Sulforaphane 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 sulforaphane out of the reach of children.

Sulforaphane is somewhat unstable, meaning that it breaks down easily and may not stay active for very long. Because of this, sulforaphane dietary supplements may not contain as much active sulforaphane as stated on the label. Although some supplements claim to contain “stabilized sulforaphane,” it is not clear if these products contain more sulforaphane than other products or if it stays active for longer.

Due to the poor stability of sulforaphane, some supplements contain “broccoli sprout extract.” Broccoli sprouts contain both glucoraphanin and myrosinase, as well as other chemicals. When glucoraphanin is mixed with myrosinase, it turns into sulforaphane. But these two chemicals must be kept separate in order to prevent the creation of unstable sulforaphane. It is not clear how much sulforaphane, if any, may be found in these products.

Some sulforaphane supplements contain an ingredient called “sulforaphane glucosinolate.” This is another name for glucoraphanin, which turns into sulforaphane when mixed with myrosinase. But most products that contain this ingredient do not contain myrosinase. This means that your body can only turn these supplements into sulforaphane if the bacteria in your gut make myrosinase. It is not clear how many people have myrosinase in their gut or whether taking these products actually provides any sulforaphane. Read the product label closely to see which chemicals it contains.

The FDA has not tested sulforaphane 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 sulforaphane?

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. This will help them know if sulforaphane is 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.

  • Cancer
  • Schizophrenia
  • Kidney or liver problems

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

Breastfeeding. It is not known if sulforaphane passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does sulforaphane interact with foods or drinks?

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

It is unknown if drinking alcohol will affect sulforaphane.

Does sulforaphane interact with medicines (drug interactions)?

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

Overdose/Missed Dose

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

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

Sulforaphane comes in a wide range of doses, and many products that claim to contain sulforaphane actually contain glucoraphanin, a chemical that must be turned into sulforaphane. Read the product label closely, and speak with a health care provider about how to take sulforaphane safely. Do not take double or extra doses, even if you miss a dose.