What Is Arnica Gel—and Does It Work?

Arnica is a homeopathic, plant-based remedy you apply to the skin or take orally. Arnica gel, cream, and tablets are available over the counter, online, at drugstore chains, or at your local natural grocery store.

Topical arnica has been shown to help relieve pain in people with osteoarthritis (OA). Some people use arnica gel and cream to temporarily ease muscle pain and treat bleeding, bruising, and swelling after surgery. However, more research is needed to evaluate its efficacy.

The Food, Drug, and Cosmetic Act (FDCA) regulates homeopathic products like arnica. However, the Food and Drug Administration (FDA) does not evaluate these products' safety or efficacy. Some online users leave rave reviews, but it's a good idea to learn about arnica gel, including what it's used for and whether it works.

What Is Arnica? 

Arnica comes from the flowers of the arnica plant, which is closely related to the common daisy and sunflower. The arnica plant mainly grows in mountainous regions in Europe, East Asia, Canada, and the Northern United States. Arnica contains helenalin, which acts as an anti-inflammatory in small amounts.

Uses 

People often use topical oral arnica to reduce OA-related pain and bruises, bleeding, and swelling after surgery. You apply arnica gel or cream to the affected area and then massage it into your skin. You can also take arnica orally, which is sold over the counter in tablet form. Oral arnica is commonly used to treat a sore throat and pain after dental work.

Arnica is typically available in 5C–30C dilutions, meaning arnica has been diluted 100-fold five to 30 times. Research has shown, however, that these doses are not standardized. Different topical and oral formulations may have varying doses, which can be unsafe. Side effects are likelier to occur with high doses.

Does Arnica Work?

The effectiveness of arnica is controversial. Some homeopathic healthcare providers swear by its efficacy, as do many users, but limited scientific evidence exists. 

Topical arnica might treat OA-related pain. OA is a type of arthritis that causes painful, stiff, and swollen joints. A review published in 2021 noted that people with hand OA experienced moderately less pain after applying arnica gel for three weeks. More research is needed, however, to know whether arnica alleviates swelling and treats muscle pain.

"Though [research] may sound promising, further clinical studies need to be conducted in order for this to be a proven remedy," Kim Tran, PharmD, a pharmacy manager at Jackson Health System, told Health. "The efficacy of helenalin for treatment of pain and swelling, when applied topically, is not supported by the currently available evidence at doses of 10% or lower."

Arnica Side Effects

Topical arnica is generally safe for short-term use, although researchers have not yet widely studied its efficacy. Side effects of topical arnica are rare and may include itching, redness, and skin irritation. No longer apply the product if you develop an adverse reaction. You'll want to avoid applying topical arnica to broken skin or mucous membranes, which can be unsafe.

It's unclear whether oral arnica is safe. Side effects may include:

• Diarrhea
• Drowsiness
• Dry mouth
• Headache
• Vomiting
• Weakness

Do not consume arnica in amounts higher than what's found in food. Taking arnica in high amounts may cause heart damage, organ failure, coma, and death.

Precautions

Topical and oral arnica are likely unsafe if you are pregnant or breastfeeding. There's not enough research to know how arnica affects pregnant and breastfeeding people. Arnica may cause bleeding during and after surgery, so do not use it two weeks prior to any procedure.

Arnica may cause an allergic reaction in people who are allergic to ragweed and similar plants, including chrysanthemums, daises, and marigolds. Talk to a healthcare provider before using arnica if you are unsure whether it's safe.

A Quick Review

Some people praise arnica, a plant-based remedy you apply to the skin or take orally. It's used to reduce OA-related pain and bruises, bleeding, and swelling after surgery. However, there's a lack of strong evidence to support how well it works.

Topical arnica is generally safe to try unless you are pregnant, breastfeeding, or have a ragweed allergy. It's unclear whether oral arnica is safe, and many experts warn against using it. Consult a healthcare provider before trying topical or oral arnica if you are unsure whether it's safe for you.