Lavender Benefits and Side Effects
Lavender aromatherapy may benefit anxiety and insomnia. Lavender oil, traditionally used as an antiseptic agent, is now predominantly used as a relaxant, carminative, and sedative in aromatherapy. Lavender is originated from Mediterranean area and its neighborhoods and now it is cultivated over the world. English lavender ( L. angustifolia ) is the most common species of lavender used in the herbal medicine.
Lavender benefits uses- research studies
Lavender benefits of muscle relaxation.
In a preliminary experiment, Japanese researchers found that lavender essential oil relaxed vascular smooth muscle. They further discovered a chemical called linalyl acetate as the major ingredient to cause the relaxation effects on rabbit vascular smooth muscle. Linalyl acetate produced sustained and progressive relaxation during the contraction through partially activation of nitric oxide/cyclic guanosine monophosphate pathway, and partially MLC dephosphorylation via activating MLC phosphatase.
Lavender benefits - insomnia and depression
In a 4-week study, Korean researchers supplied 42 women suffered from insomnia with lavender fragrance, they found improvements in insomnia and depression. In several occasions medications are often prescribed for these conditions, but it can become a problem in the long run if you become dependent to them, if so seeking drug rehabilitation is a definite option.
Lavender benefits - high blood pressure.
Japanese researchers showed that olfactory stimulation with scent of lavender oil or its component - linalool lowered renal sympathetic nerve activity and blood pressure and elevated gastric vagal (parasympathetic) nerve activity in urethane-anesthetized rats.
Lavender benefits - appetite
Japanese researchers observed that olfactory stimulation with scent of lavender oil suppressed sympathetic nerve activities and elevated gastric vagal (parasympathetic) nerve activity, decreased plasma glycerol concentration and body temperature, and enhanced appetite in rats. A 15-min daily exposure to scent of lavender oil increased food intake and body weight in the study.
Lavender benefits - pain relief.
Eight sessions of acupressure with aromatic lavender oil were found to be an effective method for short-term neck pain relief. Use of Lavender oil during recesses may improve work efficiency. A study of 36 healthy male students randomly assigned to exposure to aroma or not exposed to aroma during recesses significantly higher attention levels for the lavender group than for the control group. Probably, lavender aroma allows a better rest.
Lavender benefits - anxiety and agitation.
Researchers stimulated dental procedures patients with lavender during their waiting in a study of 200 patients. They found that ambient odors of orange and lavender reduced anxiety and improved mood in patients waiting for dental treatment. Use of odors is helpful in reducing anxiety in dental patients. Researchers also found that a Lavender aromatherapy hand massage program is effective on emotions and aggressive behavior of elderly with dementia of the Alzheimer's type.
Researchers from UK found psychologically positive mood changes after the bathing regimen (20% lavender oil and 80% grapeseed oil) for energetic arousal, tense arousal, hedonic tone and anger-frustration in a study of eighty women not receiving treatment for psychological disorders.
Researchers also found that lavender oil administered in an aroma stream showed modest efficacy in the treatment of agitated behavior in patients suffered from severe dementia.
Japanese researchers claimed that lavender odorants were associated with reduced mental stress and increased arousal rate. In the study, the researchers placed subjects into a (2 x 2- x 3 m) sound protected room for 20 min without the presentation of an odor, an analogous group of 15 received the odor oil, and one group of 13 received a non-stressful condition. They then analyzed the responses from the Cox and Mackay's stress/arousal adjective checklist.
Lavender benefits - cancer risks.
Researchers from Italy showed lavender oil exerted strong antimutagenic activity, reducing mutant colonies in the TA98 strain exposed to the direct mutagen 2-nitrofluorene. Antimutagenicity was concentration-dependent: the maximal concentration (0.80 mg/plate) reduced the number of histidine-independent revertant colonies by 66.4%. Lavender oil (0.80 mg/plate) also showed moderate antimutagenicity against the TA98 strain exposed to the direct mutagen 1-nitropyrene.
Lavender benefits of anti-bacterial activities.
Spanish lavender essential oils exhibited a very strong antibacterial activity against the tested bacteria in a test-tube study.
Lavender benefits for hair
No report is found to support lavender has benefits for hair, as of August 27, 2011
SIDE EFFECTS OF LAVENDER OIL - Are there lavender benefits for skin?
"By massaging lavender oil into the skin, it can be used to treat skin problems such as acne, burns, dry skin, eczema, itchy skin, sunburn, seborrhea, and skin inflammation." -- this claim appears in several websites. What actually reported in scientific journals about lavender "benefits"
A study of 635 women on perineal discomfort reported no side-effects of lavender oil.  However, it was found that lavender oil is cytotoxic to human skin cells in vitro (endothelial cells and fibroblasts) at a concentration of 0.25% (v/v) in all cell types tested (HMEC-1, HNDF and 153BR). It may be related to cell membrane damage.
Further, lavender oil lacks natural protection against autoxidation, and that air-exposed lavender oil can be an important source of exposure to allergenic hydroperoxides. [A1] Sköld M, and co-workers at Göteborg University report that linalool, present in lavender oil, autoxidizes on air exposure, forming allergenic oxidation products. Oxidized linalool was found to be a frequent cause of contact allergy in a patch test study on consecutive dermatitis patients. Linalyl acetate, the main component of lavender oil is commonly used as a fragrance chemical in scented products. They investigated the autoxidation of linalyl acetate and the influence of oxidation on its sensitizing potency and concluded that autoxidation of the weakly allergenic linalyl acetate leads to formation of allergenic oxidation products.
Toxicity for albino rats was reported to be very low.  However, lavender may increase the amount of drowsiness caused by some drugs. In theory, lavender may also add to the effects of cholesterol-lowering drugs. I would not apply excessive amounts of lavender oil to my skin. Please consult with your doctor for the use of lavender oil or other lavender products.