Horse ointment

Horse ointment is a valuable preparation for the treatment of various skin conditions. Horse ointment originated in China and has a history of more than 4,000 years. Its usage was recorded in many ancient Chinese medical books. Lingshu jing was the first pharmacopoeia that included information about the highly moisturising properties and effectiveness in the treatment of milia of horse ointment. Li Shizhen, a well-known Chinese physician and writer of Compendium of Materia Medica, mentioned the use of horse ointment in the treatment of dyschromia, eczema, and burns. The famous doctor Tao Hongjing also mentioned in Compendium of Materia Medica that horse oil can help to promote hair growth.

The following table summarises the major ingredients commonly found in horse ointment formulations, their effects on the skin, as well as the safety score determined by the US Environmental Working Group (EWG).[4] Horse oil cream of different brands may have slight variations in their formulations. The table below only indicates the major ingredients commonly found in horse oil cream formulations.

Ingredient safety points are quoted from the EWG US Environmental Working Group. They are used to indicate the potential risks of long-term use of the ingredient to human skin and health. Ingredient safety points range from 1-10, with 10 representing the highest risk and 1 representing the lowest risk.

Overall, the safety points of ingredients commonly found in horse ointment formulations ranges between 1-4, indicating a low risk of causing skin or other health issues. Although horse ointment itself is a nature skin moisturiser, different ingredients might be added in the production process to mask the special odour of horse oil as well as to add nutrients that can attenuate the skin replenishing effect of horse ointment.

The extraction of horse oil is a complex process that requires the use of large-scale machines. Horse fatty tissues are first ground with a meat grinder and then mixed with water. Rendering horse oil adopts a step-wise approach. Horse fat is first extracted in a vacuum system at a temperature between 60–110 °C. Rendered horse oil is then collected, filtered, and neutralized with 0.2% sodium hydroxide. It is then transferred to a stainless steel container in a water bath at 100 °C for 30 minutes for the precipitation of impurities.[5] Modern manufacturing of horse ointment usually involves purification to remove the unique odour of horse oil, which enables it to be a useful cosmetic product widely used nowadays.[6]

A typical high-purity grade of horse ointment is composed predominantly of unsaturated acids. Compared to saturated acids, unsaturated acids are more suitable for skin applications. Two major substances in horse ointments make it a good remedy for skin conditions, namely alphalinolenic acid and linoleic acid. Alphalinolenic acid is an essential omega-3 fatty acid that exerts anti-inflammatory effects, while linolenic acid is an omega-6 fatty acid that moisturizes the skin to prevent dryness and reduces inflammatory mediators.[7] In addition to its skin repairment property, a recent study discovered that horse ointments could also provide a protective effect against oxidative stress. Experimental results showed that horse ointments absorb UVB radiation and remove reactive oxygen species, thus protecting human HaCaT keratinocytes from UVB-induced oxidative stress and preventing cell structural damage, skin necrosis, and aging.[8]

Although horse ointment is generally considered safe for topical use, it may still cause allergic reactions in some people. Symptoms of an allergic reaction may include rash, itching, swelling, and difficulty breathing. If you experience any of these symptoms after using horse ointment, stop using it immediately and consult a doctor. Additionally, horse ointment is not recommended for use on broken or irritated skin, as it may cause further irritation or infection. As with any new skincare product, it is recommended to perform a patch test on a small area of skin before applying it to larger areas of the body.

Horse oil is one of the most common natural moisturising ingredients in cosmetic products in Asian countries. It has been claimed to have antibacterial, anti-inflammatory, and antipruritic effects on the skin. However, most studies related to the efficacy of horse oil are written in Japanese or Korean without any English translations, thus making it difficult for dermatologists to analyze and discuss the findings.[13]

Horse oil is extracted from a mixture of fat from the manes, tail root, and abdomens of horses in alpine regions, which raises ethical concerns. Some vegetarians and animal-rights activists hold firm to their belief that using horse for the production of horse ointment is extremely cruel and unsustainable.

After refining, horse oil is a high-quality raw material for the production of high-end cosmetics, with a huge market potential. The development and production of horse oil ointment and other associated cosmetic products have extended the chain of horse product development, increasing the output value year by year. Horse ointment is now widely produced mainly in the Kyushu area.