Adkison JD, et al. The effect of topical arnica on muscle pain. Ann Pharmacother. 2010 Oct;44(10):1579-84.
This was a randomized, double-blind, placebo-controlled trial that enrolled 53 subjects. The goal of this study was to to determine whether topical Arnica montana cream could decrease subjective leg pain following calf raises. Each patient received two tubes of cream: one containing arnica and the other containing placebo. The creams were applied to the right or left calf (as directed by labels on the tubes) immediately after exercise, and again 24 and 48 hours post-exercise. Subjects used an analog scale to rate pain severity at baseline, and at 24, 48, and 72 hours after exercising. At 48 hours post-exercise, ankle range of motion and muscle tenderness were also measured. There were no significant differences in pain scores for the legs treated with the arnica or placebo creams at baseline. However, 24 hours post-exercise, pain scores for the arnica-treated legs were significantly higher than placebo (p<0.005). Pain scores for the arnica and placebo creams were not significantly different at 48 and 72 hours post-exercise. No significant differences in ankle range of motion or muscle tenderness were detected for the two treatments.
Leu S, et al. Accelerated resolution of laser-induced bruising with topical 20% arnica: a rater-blinded randomized controlled trial. Br J Dermatol. 2010 Sep;163(3):557-63.
This double-blind, randomized, controlled study investigated the effect of a topical arnica formula on the resolution of skin bruising. The study enrolled 16 patients who then had two bruises created on each bilateral upper inner arm, by a pulsed dye laser. One of 4 topical agents (5% vitamin K, 1% vitamin K/0.3% retinol, arnica, or white petrolatum) was randomly assigned to treat one of the 4 bruises. Each treatment was applied to the assigned bruise twice daily under occlusion, for 2 weeks. A dermatologist rated the severity of the bruises at baseline and after 2 weeks of treatment. Improvement in bruise severity score was found to be significantly greater for arnica than for white petrolatum (p=0.003) or 1% vitamin K/0.3 retinol (p=0.01). Bruise reduction was also found to be nominally better with arnica than with 5% vitamin K, but the difference was not statistically significant. The investigators concluded that topical arnica ointment may reduce bruising more effectively than placebo or low concentraiton vitamin K formulations.
Ross SM. Osteoarthritis: a proprietary Arnica gel is found to be as effective as ibuprofen gel in osteoarthritis of the hands. Holist Nurs Pract. 2008 Jul-Aug;22(4):237-9.
This study was a randomized, double-blind, controlled, multicenter study that enrolled 204 outpatients with osteoarthritis of the interpharyngeal joints. Patients were randomized to receive 5% topical ibuprofen or arnica gel 3 times daily for 3 weeks. Patients were also allocated a preset number of acetaminophen tablets to be used as a “rescue treatment” if the pain was unbearable. Study results indicated that the arnica gel was comparable to ibuprofen gel with respect to hand functional capacity, pain intensity, number of painful joints, duration and severity of morning stiffness, and acetaminophen consumption. The researchers concluded that arnica gel can be used as an alternative to ibuprofen gel in patients with osteoarthritis of the hand.