Gastroesophageal reflux disease (GERD) causes persistent and recurring acid reflux. Doctors often prescribe antacids or proton pump inhibitors (PPIs) to manage the symptoms, but some people prefer to use alternative approaches, such as d-limonene.

D-limonene is a compound that comes from citrus peel. Some proponents of taking d-limonene for GERD argue that, unlike antacids and PPIs, d-limonene can reduce the symptoms of GERD without lowering stomach acid production, which is important for digestion and keeping the digestive tract healthy.

However, there are few high quality studies proving that this works in humans. So far, the main evidence supporting its use is anecdotal.

This article looks at d-limonene, whether it helps with GERD, its safety, and potential side effects.

Close-up of the rind of a sliced lemon, which is a source of d-limonene.Share on Pinterest
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D-limonene is a chemical compound that naturally occurs in the peel of citrus fruits, such as oranges or lemons. It belongs to a family of chemicals known as terpenes. People can purchase d-limonene as a dietary supplement. Companies also use it to give foods and beverages a citrus flavor.

Some scientists believe that d-limonene could have a range of beneficial effects on health, such as:

Few studies that have tested if d-limonene reduces GERD symptoms in humans. Many of the existing research involves animals rather than human participants.

For example, a 2019 animal study demonstrated the protective effects of d-limonene on the gastrointestinal system in rats. The authors suggested that d-limonene produces its beneficial effect by increasing mucus production and regulating the inflammatory and immune responses.

A 2022 study also mentions two human clinical trials in which participants with GERD “significantly benefitted” from taking d-limonene. These trials took place under a United States patent in 2002.

However, a 2017 study highlights that, at present, there are few large, high quality studies to prove d-limonene is an effective approach. This means more research is necessary to confirm its use as a treatment for GERD.

The Food and Drug Administration (FDA) considers d-limonene to be “Generally Recognized As Safe” (GRAS) when companies use it to add flavor to foods. This means that, in moderate doses, it is safe to ingest.

An older study reports that this substance has a low toxicity risk, which means a person would have to take a high dose to experience poisoning.

Some also argue that d-limonene could be useful for other conditions. For example, a 2021 study argues that, as a relatively safe substance, d-limonene could potentially reduce inflammation in people with COVID-19.

However, the FDA has not approved d-limonene as a medication for GERD. This means it has not undergone rigorous tests for safety or effectiveness. It also means that companies selling d-limonene as a supplement do not need to prove its purity.

Additionally, people with allergies to citrus fruits may not be able to take d-limonene. There is not enough evidence to say whether d-limonene is safe to take for those who are pregnant, breastfeeding, or who are children.

People who want to try this approach should consult their doctor first. When purchasing d-limonene, always look for reputable brands where third-party laboratories have tested the d-limonene to ensure its quality.

There is no standard or agreed-upon dose for d-limonene. The lack of human studies makes it difficult to state what dosage will have the most effect.

However, d-limonene supplements tend to come in a range of dosages, including:

  • 250 milligrams (mg)
  • 500 mg
  • 1,000 mg

If a doctor says it is OK to take d-limonene, start with the lowest dosage. If it does not work, a person may want to try a higher dose.

Research suggests that d-limonene is safe for most people to take orally. However, there is a lack of data on the potential side effects and how often they occur, so some people may have adverse reactions to this supplement.

Potential adverse effects include:

D-limonene may interact with certain medications. For example, it may affect how well the liver breaks other medications down. This could interfere with medical treatment and result in a range of adverse effects.

Additionally, some liver enzymes help the liver process limonene. Drugs that increase how well the liver can do this may decrease the effects of a d-limonene supplement.

While d-limonene appears safe, it is always a good idea to talk with a doctor before trying any supplement. Some questions to ask include:

  • Could d-limonene help with GERD?
  • Can I take it at the same time as my other medications?
  • Are there any good brands you recommend?
  • How much should I take?
  • When and how often should I take d-limonene?

D-limonene is a naturally occurring chemical present in citrus fruits. Animal studies and a limited number of human trials suggest that this substance may have a protective effect on the gastrointestinal tract. Some report it reduces GERD symptoms.

However, more research is necessary to confirm if d-limonene is a safe and effective GERD treatment. Anyone planning to take d-limonene should consult their doctor first, particularly if they are taking other supplements or medications or if they are pregnant.