Do arnica pills, gels, creams, or sprays reduce bruising, pain, or swelling?

Answer:

Arnica montana is a flowering plant that contains a variety of compounds — some of which may be helpful, but others that can be poisonous and, for this reason, it is considered a dangerous plant.

Nevertheless, arnica has been used by some as an oral homeopathic preparation (i.e., at an extreme dilution that contains little to no arnica) to prevent bruising after surgery. It is also applied topically as a gel, ointment, cream or spray to treat bruising, swelling, and pain. However, as explained below, the clinical evidence is not compelling for any oral or topical use.

Homeopathic arnica pills

Arnica is commonly used as a homeopathic preparation to prevent bruising after surgery. However, the clinical evidence of its effectiveness is not compelling and, scientifically, there is little reason to expect it have an effect, as explained below.

What is a homeopathic preparation?
Arnica as a homeopathic preparation is essentially the opposite of an herbal preparation in which particular material or compounds from an herb are extracted and often concentrated. With homeopathic preparations the herb is diluted to such an extreme that the final product is not likely to contain a single molecule of the original material. Homeopathic practitioners believe that some kind of "energy" or "imprint" remains, even if no physical substance does. In fact, they believe that the higher the dilution, the stronger the effect, and call highly dilute homeopathic preparations "high potency" remedies.

Homeopathic ingredients labeled as “HPUS” indicate the ingredient was diluted using Homeopathic Pharmacopoeia of the United States standards. However, be aware that homeopathic products have not been approved by the FDA for any use, and the agency advises that they “may not meet modern standards for safety, effectiveness, and quality.”

The letter “X” indicates that each time a substance was diluted (which is sometimes indicated by the term ”radix”) it was done so at a 1:10 dilution. For example, an ingredient that is listed as “radix 2X” was diluted twice - diluting the substance with one part herb to 10 parts water (or other liquid used to dilute), and then the resulting substance is diluted a second time at a 1:10 dilution. Therefore, a product that is labeled as containing “Arnica montana radix 2X 15 mg” should contain 0.15 mg of arnica.

The letter “C” indicates that each time a substance was diluted it was done so at a 1:100 dilution. Therefore, an arnica homeopathic product that lists its "active ingredient" as "Arnica montana 30C HPUS" is actually implying that the arnica was diluted 10³⁰ times (i.e., 10 followed by 30 zeros).

As a representative of one of the major homeopathic brands once told a ConsumerLab staff member inquiring about how they analyze the quality of homeopathic medicines, "There's no active ingredient to test for."

What the research says about oral arnica
While homeopathic arnica is unlikely to contain any active ingredient, it has nevertheless been tested for its efficacy in several clinical trials. In studies that compared it to placebo in patients undergoing treatment for varicose veins or hand surgery, as well as facelift procedures, arnica was no better than placebo in terms of reducing bruising (Ramelet, Dermatology 2000; Wolf, Forsch Komplementarmed Klass Naturheilkd 2003; Stevinson, J R Soc Med 2003; Seeley, Arch Facial Plast Surg 2006). A more recent study in which nine rhinoplasty (i.e., "nose job") patients treated by a single surgeon were given homeopathic arnica (SinEcch from Alpine Pharmaceuticals) suggested modest benefit (up to 33% smaller bruise area and up to 36% reduced color intensity on average) compared to results from 13 other patients given placebo, but the results were only statistically significant on certain days — there was actually somewhat increased bruise color intensity two days after surgery among those that took arnica compared to those receiving placebo (Chaiet, Ann Plast Surg 2016).

Combination formulas containing arnica
Some popular oral homeopathic formulations that are promoted for reducing joint and muscle pain, as well as for bruising, contain arnica in addition to other ingredients.

For example, Traumeel Analgesic tablets (HEEL Company, Germany, distributed in the U.S. by MediNatura), contain Arnica montana (radix 2X 15 mg, i.e., 0.15 mg of arnica per 300-mg tablet) along with homeopathic dilutions of many other herbs and metals.

Although animal and laboratory studies suggest that Traumeel may have anti-inflammatory effects (Jordan, Pharmaceuticals 2021; Porozov, Clin Dev Immunol 2004), results of studies in people given Traumeel tablets have generally not yielded favorable results. For example, taking Traumeel after surgical bunion removal (two tablets five times daily for the first three days after surgery, and two tablets three times daily for another 10 days) did not reduce pain or use of pain medication after surgery compared to placebo (Singer, BMC Clin Pharmacol 2010). Similarly, Traumeel tablets (eight tablets taken immediately after exercise, followed by two tablets at 6 hours and 10 hours post-exercise, and two more tablets the morning after exercise) did not reduce self-reported muscle pain in healthy, untrained young men in a 24-hour period after strenuous exercise compared to placebo - although Traumeel had a modest, beneficial effect on certain markers of exercise-induced immune system inflammation (Pilat, Scand J Med Sci Sports 2015).

Somewhat more favorable results have been reported in several studies using Traumeel topically, as an ointment, or a gel (which does not appear to be available in the U.S.,) as discussed below, and some preliminary, company-funded studies suggest a benefit for joint pain when given as an injection, although Traumeel injections are no longer available in the U.S. There do not appear to be studies on the effects of Traumeel tablets for joint pain.

Slightly modified versions of the Traumeel formula, sold as T-Relief tablets and cream (discussed below) are made by the same manufacturer and contain the same amounts of arnica and other ingredients as in Traumeel but do not contain Mercurius solubilis (soluble mercury) and Henar sulfuris (calcium sulfide), and have not been studied in clinical trials. Both the original Traumeel tablets and ointment, and T-Relief tablets and cream, are sold in the U.S.

Topical arnica

Arnica applied topically has shown only mixed results for minimizing bruising, swelling, and pain. It is possible that any benefit may depend on the concentration of arnica in the product, but overall, there is not enough information to conclude that topical arnica is effective for any particular use.

Types of topical arnica
There are two very different types of topical arnica: Herbal arnica, which contains actual arnica (typically from the flowers of the herb Arnica montana) at a concentration ranging from about 2% to 25%, and homeopathic arnica, which is made with arnica that, as described above, can be extremely dilute and contain little to no arnica.

What the research says about topical arnica
A review of 11 small studies performed prior to 2013 with various topical formulations of arnica concluded that "...if Arnica has an effect, it is probably not present at lower dosages, but only at dosages of 10% or more" and "...the effect of topical Arnica, if it exists, is only moderate" (Brito, J Musculoskel Pain 2014). The review focused mainly on herbal arnica, but included some studies using homeopathic arnica preparations that were not as dilute as those typically used in arnica pills. However, an overall assessment of arnica by European authorities that evaluated many of the same studies did not approve arnica as a medicine because "...the clinical trials are of limited quality and a well-established use cannot be justified" (European Medicines Agency, 2013).

Among the studies evaluated in the reviews noted above is one involving people with varicose veins that found that applying 2% arnica ointment provided no benefit, while a similar study using a 25% arnica ointment showed reduced pain (Brock, 1991; Brock 2001). Another positive study compared 20% arnica in petroleum jelly to placebo (jelly alone) in people with laser-induced bruising: Two weeks after injury, there was slightly more improvement with arnica, with bruises improving by 4.1 points with arnica versus 3.7 points with placebo on a bruising scale 1 to 10 (Leu, Derm Surg Lasers 2010). Another study of laser-induced bruising using a 10% arnica ointment or placebo applied twice daily for two weeks showed no significant difference between arnica and placebo (Alonso, Dermatol Surg 2002).

Results of studies of topical arnica for post-exercise muscle pain have been mixed. A double-blind study of leg pain following calf raises in which an arnica cream or a placebo was applied after exercise and then daily for two days found that, compared to placebo treatment, there was a slight increase in leg pain 24 hours after exercise when arnica was applied, but there was no difference in pain at two days, and there was no difference with regard to muscle tenderness and ankle range of motion. The arnica cream was "1X HPUS-7%," meaning 0.7% arnica (Adkinson, Annals of Pharmacother 2010). A later placebo-controlled study showed some reduction in muscle pain from downhill running by applying a 1% arnica gel to the legs every 4 hours. However, there were no reductions in biochemical markers of muscle damage or inflammation, nor improvement in running performance (Pumpa, Eur J Sport Sci 2014).

Combination formulas containing arnica
Traumeel Analgesic Ointment contains all of the homeopathic ingredients found in Traumeel tablets - although in different amounts, providing 1.5 mg of homeopathic arnica per 100 grams, for example, compared to 0.15 mg per tablet. Results of studies using topical Traumeel have been somewhat more positive than those using Traumeel tablets, but most have been company funded and some have not included a placebo-control. A company-funded study in Spain, for example, compared 2 grams of the ointment or gel (applied three times daily for two weeks) to a topical non-steroidal anti-inflammatory drug (1% diclofenac). Similar decreases in pain were reported with all three treatments among 372 men and women with a mild to moderate ankle sprain initially treated with standard treatment (rest, ice, compression, elevation). Adverse events, such as headache, rash, and dry skin, were rare and generally mild, and occurred at similar rates in both groups. The study did not include a placebo group, limiting the significance of the findings (Gonzalez de Vega, Int J Clin Pract 2013).

Traumeel ointment was reported to reduce pain and swelling, and improve function compared to a placebo ointment in a 2-week study in men and women with ankle sprains, and a 15-day study in adults with various sport-related musculoskeletal injuries; however, these studies were originally published in German, and details do not appear to be available (Zell, Fortschr Med 1988; Schneider, Int J Gen Med 2011). There do not appear to be any published clinical trials on the effects of Traumeel, taken orally or used topically, for reducing joint pain in people with osteoarthritis or rheumatoid arthritis.

A modified version of topical Traumeel, sold as T-Relief Pain cream, is also available in the U.S. The difference is that T-Relief does not contain Mercurius solubilis (soluble mercury) and Hepar sulfuris (calcium sulfide), and contains aloe, soybean, safflower, and coconut oils, and shea butter instead of petroleum as a base. There are no published clinical studies using T-Relief cream.

Safety and side effects of arnica

If used as directed (typically starting around the time of surgery and continuing for a few days afterward), oral homeopathic arnica pills are likely to be safe. A small study in the U.S. among 20 men and women aged 18 to 75 who took two tablets of Traumeel (which contains arnica along with many other homeopathic ingredients) three times daily for four weeks found no changes in blood cell counts, blood markers of liver and kidney function, and no changes in blood pressure or heart rate, compared to baseline. Headache was the most commonly reported adverse event (15 participants) followed by indigestion (11) and diarrhea or bloating (6), and all were considered mild to moderate (Arora, Biol Ther 2000).

Be aware that homeopathic arnica pills contain other ingredients to give them consistency, such as lactose, which may not be suitable for some people.

A laboratory study found that arnica contains constituents that inhibit aggregation of human platelets (Schroder, Thromb Res 1990). Until more is known, arnica should be used with caution in people taking blood-thinning medications such as aspirin, warfarin (Coumadin) or heparin, or anti-platelet drugs such as clopidogrel (Plavix), and should be discontinued 2 weeks prior to surgery to reduce the risk of excessive bleeding (Lazo, J Clin Anesth 2024).

An assessment of arnica by European authorities found that topical use appears to be safe in adults and adolescents, although it may cause allergic reactions in some people. Also, it has not been adequately evaluated for use in children or during pregnancy or lactation (European Medicines Agency, 2013). As noted above, mild side effects such as headache, rash, and dry skin have been reported with use of Traumeel, which contains homeopathic arnica along with many other homeopathic ingredients.

Quality concerns with arnica

Arnica montana is the only official species of arnica listed in the European Pharmacopoeia, but other arnica species, including A. angustifolia, A. chamissonis, A. chamissonis subsp. foliosa, A. cordifolia, A. latifolia, and A. sororia, may be sold as "arnica" in the United States. These other species are considered by some herbalists to be interchangeable and have similar effects as Arnica montana. In fact, A. chamissonis subsp. foliosa was approved by the German Commission E as a substitute for Arnica montana in certain topical preparations (Gafner, Botanical Adulterants Bulletin 2016).

However, other plants have also been found in arnica products, likely added as cheaper ingredients substituted for arnica. This is considered to be "common" in the U.S., although there is no published information regarding the frequency (Gafner, Botanical Adulterants Bulletin 2016), and there is increased concern of adulteration to due to a 7- to 8-fold increase in price of arnica raw materials in 2022 since 2019 (American Botanical Council Press Release 2023). The most well-known arnica adulterant is Heterotheca inuloides, commonly referred to as Mexican arnica. While adulteration of arnica with Heterotheca inuloides is not considered to have any safety concerns, it is unclear if it has similar clinical effects as arnica. Although less common, other arnica adulterants may include C. officinalis (calendula) or other species from the aster family, as well as some species from the loasa plant families (such as Mentzelia conzattii). Some of these species, including C. officinalis, may cause side effects such as allergic reactions or asthma exacerbations, in some individuals (Kazmierski, Chest Annual Meeting October 18-21, 2020).

A consumer advocacy group filed a lawsuit against the homeopathics company Boiron in April 2022 for allegedly deceiving customers about the effectiveness of its products. As part of the lawsuit, the advocacy group purchased Boiron Arnica Montana 30C pellets, which are marketed "for pain relief" and, upon testing, alleges that it found that the product mainly consisted of table sugar, but also included silicon (24.3%), which was not disclosed as a product ingredient. Ten years earlier, in 2012, Boiron agreed to pay $5 million to customers and others in a legal settlement for falsely claiming its products (including Arnicare) provide relief for symptoms of common ailments. The company also agreed to modify packaging of the products to note that the "Uses" have not been evaluated by the FDA.

Cost

Most homeopathic arnica products, which are unlikely to contain any active ingredient, can be expensive. For instance, VitaMedica's Arnica Montana 30X HPUS costs $18 for 120 tablets. Based on the suggested serving (3 tablets, 3 times daily), the cost of taking this product would be about $1.08 per day. Although slightly less expensive, Boiron's Arnica Montana 30c Homeopathic Medicine for Muscle Pain and Stiffness, which costs about $13 for 240 pellets and suggests 5 pellets be taken 3 times daily, would still cost about 75 cents per day. T-Relief tablets (2 tablets every 4 hours) are less expensive than Traumeel tablets (1 to 2 tablets 3 times per day) ($14.99 vs. 26.99 for a bottle containing 100 tablets).

Very few topical products on the market appear to contain at least 10% arnica, which seems most likely to have benefit (if any), and those that do are somewhat expensive. For instance, Arnica Essence by Uriel, which appears to contain 10% arnica, costs $29 for 4.2 fl. oz ($7/ounce). Meanwhile two products that contain only 0.7% arnica, Boiron's Arnicare Gel and brazzoMD's Arnica 7 Cream, cost $5.33/ounce and $13/ounce, respectively. MediNatura's T-Relief Homepathic Cream, which contains arnica along with other ingredients, costs about $6.50/ounce) but provides only 0.2% arnica. Even VitaMedica's Arnica+K Cream, which costs a whopping $52/ounce contains only 0.3% arnica (along with other ingredients). Be aware that some topical arnica products may appear to contain more arnica than what is actually included. For instance, Uriel's Arnica 20% Gel (formerly Arnica Forte Gel), which costs about $14.50/ounce, might be assumed to provide 20% arnica, but it lists "100 gm contains: 20 gm Arnica 1X," meaning it actually contains only 2% arnica.

Traumeel ointment and T-Relief cream cost about the same per ounce ($7.64 vs $7.49), although Traumeel comes in a larger tube (3.53 oz) than T-Relief, so Traumeel has a higher purchase price ($26.99 vs $14.99).