Onion Interactions Overview

Additional Details

Is Onion Safe to Use? Are There Any Precautions?

Onion is considered safe when consumed in amounts commonly found in foods and has Generally Recognized as Safe (GRAS) status in the US. Topical use of onion extract is also generally safe. However, pregnant and lactating individuals should avoid using onion in amounts greater than what is typically found in foods due to insufficient reliable information available.

Common Side Effects to Watch For

When used orally, onion is generally well tolerated, but some common adverse effects may include abdominal pain and heartburn. Topical use of onion may rarely cause eczema or irritation. In sensitive individuals, onion can rarely trigger anaphylaxis.

What Is Onion Typically Used For?

There is evidence to suggest that topical application of onion extract, usually as part of combination products, may be beneficial for preventing scarring. However, the most effective combination, dosage form, and dose are still unclear. The use of dietary onion or onion supplements for weight loss is not supported by clinical research. There is insufficient reliable evidence to rate onion for other uses, including alopecia areata, angina, asthma, atherosclerosis, bruises, diabetes, dyspepsia, gastric cancer, hypertension, hypothyroidism, insect bites, insomnia, polycystic ovary syndrome (PCOS), prostate cancer, respiratory tract infections, stretch marks, and warts. More evidence is needed to determine the effectiveness of onion for these purposes.

Dosing & Administration

Research on the dosing of onion is limited, and typical dosing recommendations are unavailable for oral or topical use in adults or children.

Standardization & Formulation

Orally, some clinical trials have studied onion extracts standardized to quercetin content. These extracts have been provided in gelatin capsules. Topically, onion extract is often evaluated as part of combination formulations with ingredients like heparin, allantoin, gotu kola, hyaluronic acid, and pentaglycan. Other topical products have included crude onion juice and patches containing onion extract and allantoin.

How Does Onion Work? What Is the Mechanism of Action?

The bulb of the onion is the part of interest. Onion contains essential oils, di- and tri-sulfide compounds, flavonoids, and plant sterols. It is believed that the di- and tri-sulfide compounds and flavonoids, such as quercetin, contribute to various effects of onion.

• Antiasthma effects: Animal research suggests that certain onion extracts or onion oil may have protective effects on bronchial asthma, possibly due to inhibiting enzymes involved in inflammation and histamine release.
• Anticancer effects: Onion consumption is thought to reduce the risk of cancer. Organosulfur compounds and quercetin in onion have been shown to exhibit anticancer properties in laboratory studies.
• Antidiabetic effects: Onion has demonstrated hypoglycemic effects in patients with diabetes and animal models. It may stimulate insulin secretion and possess antioxidant activity.
• Antihypertensive effects: Some preliminary clinical research indicates that certain onion products may slightly decrease systolic blood pressure. Antioxidant effects of flavonoids like quercetin are believed to play a role.
• Antimicrobial effects: Onion has exhibited antibacterial and antifungal activity against various microorganisms.
• Bone effects: Onion might promote bone health by increasing bone density and inhibiting bone loss.
• Coagulation effects: Onion constituents seem to inhibit platelet aggregation and reduce the formation of inflammatory products from arachidonic acid.
• Digestive effects: Onion has been found to stimulate digestive enzymes and enhance pancreatic lipase and amylase activity.
• Lipid effects: Onion has shown hypolipidemic effects, reducing cholesterol levels. Sulfur-containing compounds appear to be involved.
• Wound-healing effects: Topical application of onion extract, often in combination with other ingredients, has been shown to improve the appearance of scars. Anti-inflammatory, antiproliferative, antibacterial, and collagen-regulatory properties may contribute to its effects.

Pharmacokinetics

There is limited reliable information available about the pharmacokinetics of onion. Quercetin, a flavonoid found in onion, can be absorbed from the digestive tract and metabolized in the liver. It is excreted in urine after consumption.

Interaction Overview (See Full List At Bottom Of Page)

Onion may interact with anticoagulant/antiplatelet drugs, antidiabetes drugs, aspirin, and cytochrome P450 2E1 (CYP2E1) substrates. Caution is advised when using onion in combination with these substances. No significant interactions are currently known with other drugs, supplements, conditions, or lab tests.

Drugs that interact with Onion