The Health Benefits of Arnica

Arnica is a genus of perennial herbs belonging to the sunflower family (Asteraceae). Several species of Arnica, mostly notably A. montana, contain an anti-inflammatory compound believed to relieve pain, aches, and bruising when applied topically. Arnica is indigenous to sub-alpine regions of western North America but can also be found in arctic regions of Europe, Asia, and North America.

Arnica plants have long downy leaves and bright yellow or orange daisy-like blossoms between 2 and 3 inches wide. The same ingredient that gives arnica its anti-inflammatory effects, called helenalin, is extremely toxic when consumed and irritating to the skin unless diluted.

Arnica is most commonly sold as an over-the-counter topical ointment, gel, or cream but is also available as an extract, tincture, oral supplement, sublingual (under the tongue) pellet, powder, aromatherapy oil, and dried "wild-crafted" herb.

Health Benefits

Arnica is commonly used in alternative medicine for the treatment of bruising, pain, myalgia (muscle soreness), and arthralgia (joint aches).

Arnica is commonly marketed by homeopathic drug manufacturers as an effective treatment for osteoarthritis, post-shingles neuralgia, diabetic neuropathy, post-surgical pain, wound healing, and even cancer, although there is limited scientific evidence supporting its use in treating any medical condition.

That is not to say that arnica is without benefits; it is simply that clinical studies investigating arnica are almost invariably small, poorly designed, and often contradictory in their findings.

Osteoarthritis

Osteoarthritis, often referred to as "wear-and-tear" arthritis, is generally treated with nonsteroidal anti-inflammatory drugs (NSAIDs). Homeopaths have long suggested that arnica, with its anti-inflammatory properties, offers a reasonable and safe natural alternative to NSAIDs.

In a comprehensive review of studies published in the Cochrane Database of Systematic Reviews, researchers from Australia analyzed seven previously published trials examining the benefits of topical herbal remedies in people with osteoarthritis.

Of the remedies studied, arnica gel appeared to work nearly as well as Advil (ibuprofen) in reducing pain and improving joint function in people with hand osteoarthritis.

However, people who used arnica gel had a higher incidence of side effects compared to Advil (13% versus 8%), and some even reported an increase in joint stiffness and pain.

Post-Surgical Pain and Bruising

Proponents of arnica believe that it can reduce bruising and swelling following surgery when applied topically or taken as an oral supplement.

A 2016 review of studies in the American Journal of Therapeutics suggested that A. montana was a "valid alternative to nonsteroidal anti-inflammatory drugs in treating post-operative pain, edema (swelling), and ecchymosis (bruising) but acceded that the results varied substantially by the formulation, dose, and study.

By contrast, another review published in Dermatologic Surgery found insufficient evidence to support the use of oral or topical arnica in treating post-surgical edema or ecchymosis.

Muscle Pain

Myalgia (muscle pain) is associated with a wide range of medical conditions as well as the simple overuse of your muscles.

Most studies investigating arnica have focused on its use in treating post-exertional myalgia. Arnica has long been used in sports supplements for just such purposes, even though there is little evidence to support such use.

A highly subjective review of studies published in the International Journal of Complementary and Alternative Medicine strongly endorsed the combined use of oral and topical arnica in treating muscle injuries even though four of the studies included in the review found no such benefits compared to a placebo.

Possible Side Effects

Arnica is known to cause side effects even when used in highly diluted topical preparations. More serious side effects can occur when taken by mouth.

Topical Use

Arnica may cause a mild allergic reaction, most notably in people with a pre-existing allergy to plants of the Asteraceae family, including ragweed, marigolds, chrysanthemums, and daisies.

Arnica can also trigger transient increases in blood pressure and heart rate, particularly if used excessively or on broken skin. Broken skin allows for greater absorption of the active ingredient and may also cause localized stinging.

Oral Use

Most homeopathic arnica remedies are extremely diluted and considered safe. However, some forms may contain detectable amounts of helenalin which may pose health risks.

When taken by mouth, arnica can cause:

• Mouth and throat irritation
• Stomach pain
• Diarrhea
• Vomiting
• Shortness of breath
• Easy bruising and bleeding
• Rapid heartbeat
• High blood pressure

Contraindications and Interactions

Arnica can slow blood clotting and should be discontinued two weeks prior to surgery to reduce the risk of post-operative bleeding, undermining its purported benefit in reducing post-surgical pain and bruising.

Because of its anti-clotting effects, arnica should be avoided if you are taking any anticoagulant (blood-thinning) drugs like Coumadin (warfarin), Plavix (clopidogrel), heparin, and NSAIDs. Doing so may increase the risk of bleeding and bruising.

Little is known about the safety of arnica during pregnancy. If you are pregnant or breastfeeding, consult your doctor before using arnica in any form.

Selection, Preparation, and Storage

Arnica montana is the species most commonly used for medicinal purposes, although chamissonis, A. longifolia, and A. gracilis are also sometimes used.

Most over-the-counter arnica preparations are repeatedly distilled, resulting in gels, ointments, and extracts with little to no helenalin. The same applies to arnica powders, capsules, and sublingual pellets that typically contain no helenalin (furthering questioning their anti-inflammatory benefits).

When purchasing arnica, look for brands that have been tested by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International. This way, you can be sure the ingredients on the product label are correct and tell if any helenalin is included in the formulation.

You should also check that the Latin name of the arnica species (such as Arnica montana) is included on the product label, and be wary of any product that claims to contain "pure arnica."

Most arnica preparations can be stored at room temperature. As a general rule, store them in their original containers away from direct sunlight and never use more the dose listed on the product label. Discard any preparation that is past its expiration date.

Common Questions

How is arnica used in aromatherapy?

Arnica oil is commonly used in aromatherapy as a carrier oil to which essential oils are added. It has a pleasant pineapple-and-sage-like scent that is said to be relaxing.

Are there natural alternatives to arnica?

In addition to arnica, herbs like belladonna (Atropa belladonna), dulcamara (Solanum dulcamara), and pulsatilla (Pulsatilla nigricans) are often used in homeopathy to treat joint and muscle pain. The common daisy (Bellis perennis) and a type of rhododendron known as marsh Labrador tea (Rhododendron tomentosum) can be applied topically to help relieve bruising.

Is arnica used in traditional Chinese medicine safe?

Arnica, known as shan jin che in traditional Chinese medicine (TCM), is said to tonify the qi (life force) and balance the yin and yang. Although touted for its curative effects, TCM remedies containing arnica pose the same risks as any other form of pure arnica.

Because herbal remedies are not subject to the same regulatory standards applied to pharmaceutical drugs, be cautious when using any such product and speak to your doctor first if you are thinking about trying one.