Rosemary oil is an essential oil extracted from the leaves of the rosemary plant, also known as Rosmarinus officinalis. Rosemary belongs to the same plant family as mint, and it has a woody scent that enhances both culinary dishes and beauty products. In ancient times, the citizens of Rome used rosemary for religious purposes, and the herb's medicinal benefits were documented in the sixteenth century by Paracelsus, a German-Swiss doctor and botanist. Paracelsus asserted rosemary could heal the liver, heart, and brain and fortify the body. Modern scientific studies have proven many of his assertions correct.
Boosts Hair Growth
Several studies have shown rosemary oil boosts hair growth in patients with androgenetic alopecia, a condition sometimes known as male-pattern baldness. Depending on testosterone levels, some female patients can also develop the condition. Dihydrotestosterone (DHT), a byproduct of testosterone, is believed to be responsible for damaging hair follicles and causing permanent hair loss in individuals with this condition. A two percent solution of minoxidil is one of the standard treatments available to patients. A 2015 study comparing this treatment option and rosemary oil found the latter increased hair just as well as minoxidil over six months. The oil also had fewer side effects than the conventional treatment, and subjects reported rosemary oil caused far less scalp itching than the minoxidil.
Studies in animals have found rosemary oil naturally inhibits DHT, and it can be especially helpful for patients undergoing testosterone treatment. Rosemary oil has also been shown to help patients with alopecia areata, a condition that leads to bald patches on the scalp. Experts estimate twenty percent of individuals over forty years old may have alopecia areata. In a seven-month study, patients rubbed either rosemary, jojoba, or grapeseed oil into their hair. While jojoba and grapeseed oils resulted in a fifteen percent increase in hair growth, rosemary oil increased hair growth by up to forty-four percent.
In traditional folk medicine, rosemary oil is often used as a mild pain reliever. A study conducted in South Korea demonstrated the oil successfully alleviates pain in stroke patients. The study was conducted over a period of two weeks and followed subjects who were experiencing shoulder pain after having a stroke. One group of patients received acupressure treatment alone, and the second group received acupressure treatment that incorporated the use of a rosemary oil blend. The acupressure treatments were given twice a day for twenty minutes.
The patients who received acupressure alone reported a fifteen percent reduction in their shoulder pain, and those who had acupressure along with rosemary oil reported a thirty percent reduction in their pain. Animal studies have concluded rosemary oil can be even more effective than acetaminophen for pain relief. Rosemary oil is most commonly used to reduce the pain of headaches and minor muscle aches, and some patients have reported it also reduces the pain they experience from arthritis.
Numerous medical conditions and medications may cause reduced circulation (blood flow). Poor circulation can result in cold hands and feet, swelling in the lower limbs, numbness or tingling in the extremities, changes in the skin color of the affected area, and pain or cramping in the muscles and joints. Research suggests rosemary oil increases circulation by expanding the size of the blood vessels, allowing blood to reach the hands and feet more easily.
The oil may be especially beneficial for patients who have Raynaud's disease, a condition that constricts blood vessels in the hands and feet. A case study led by Dr. Von Schoen-Angerer followed a patient with this condition who experienced cold hands and feet. For the purposes of the study, the patient applied both olive oil and rosemary oil to the affected areas. While the olive oil had no impact, the patient reported their hands and feet felt warmer when using the rosemary oil. Thermal imaging tests confirmed rosemary oil did indeed result in increased circulation to the patient's extremities.
May Reduce Stress
Several studies have suggested rosemary oil may reduce stress, which can cause the heart rate to be temporarily elevated. A study of nursing students taking particularly stressful academic exams measured their pulse rates before and during these exams. Some of the students were asked to inhale rosemary oil through an inhaler for the study, and the control group was not given any oil. The results showed the students who had inhaled rosemary oil experienced a nine percent decrease in their pulse, and the students in the control group had no decrease.
In addition to an increased pulse rate, stress can also cause elevated cortisol levels. A study of twenty-two adults showed those who inhaled rosemary oil for five minutes experienced a twenty-three percent reduction in cortisol. The control group inhaled a neutral oil, and no reduction in cortisol levels was demonstrated. Additional studies have shown rosemary oil may help improve mood and make patients feel more energetic.
May Ease Inflammation
One of the most powerful benefits of rosemary oil is it may ease inflammation. One condition associated with significant inflammation is rheumatoid arthritis. A study in which patients with this condition were given knee massages with or without rosemary oil concluded the addition of rosemary oil reduced knee pain by fifty percent; the control group, in which the massages were given without rosemary oil, only experienced a twelve percent reduction in pain. Patients with injuries such as tendonitis and other ailments associated with inflammation may also experience relief when using rosemary oil. Early research in test-tube studies has suggested rosemary oil may hold promise in reducing the inflammation associated with the development of cancerous tumors.