A randomized controlled study involving 60 participants found that application of a cream with a 3% concentration of marjoram, black pepper, lavender, and peppermint resulted in improved pain tolerance and increased mobility relative to the control group. Read more here.
M.-C. Ou, Y.-F. Lee, C.-C. Li, and S.-K. Wu, “The effectiveness of essential oils for patients with neck pain: a randomized controlled study,” J. Altern. Complement. Med. N. Y. N, vol. 20, no. 10, pp. 771– 779, Oct. 2014.