Fragrance Alters Mood and Brain Chemistry.
(Health Risks and Environmental Issues)

Townsend Letter for Doctors and Patients; 4/1/2004; William, Rose Marie

Fragrance materials are added to give products a scent, to mask odors of other ingredients, and in some cases to alter mood. Fragrance materials may be synthetic, natural, or a combination of both. Using scented products causes exposure to skin, upper airways, and olfactory pathways to the brain and lungs. These are all entry points to the body, causing systemic exposure as well. Fragrance inhalation through the nose goes directly to the brain where its neurological effects can alter blood pressure, pulse and mood, as well as having sedative effects. (1)


Volatile Compounds

Fragrances are volatile compounds that linger in the air adding to indoor air pollution and contribute to poor indoor air quality. Fragrance formulations often contain high concentrations of potent and long lasting synthetic chemicals for which very little data exists regarding their health and safety. The United States Environmental Protection Agency (EPA) acknowledges that poor air quality contributes to a host of physical and neurological problems including headaches, dizziness, fatigue, and forgetfulness. Eighty to 90% of fragrance chemicals are synthesized from petroleum products and are designed to disperse quickly into the air where they can linger on fabrics and surfaces for months. (1)

Fragrance is Everywhere

Fragrance chemicals are unavoidable. They are included in every personal care product, cosmetic, detergent, soap, fabric softener, pesticide, candle, car and room air-freshener. (1), (2) Hotels and motels routinely spray with fragrance or use plug-in devices to disperse a scent. Most modern facilities have windows that do not open, preventing fresh air from entering. When making room reservations this writer has begun requesting that no spray be used. Providing fragrance-free guest rooms has not yet caught on in the hospitality trade. When more consumers ask for "fragrance-free" rooms they may become more available, similar to the demand for tobacco-free rooms.


Perfumes contain neurotoxins, which have a causal link to central nervous system disorders, headaches, confusion, dizziness, short-term memory loss, anxiety, depression, disorientation, and mood swings. To avoid second hand exposure among a growing population of sensitive individuals, some high schools, workplaces, and public buildings have enacted policies banning the use of perfumes. (2), (3)

Bach Flower Remedies

Prior to humans being exposed to modern synthetic petroleum derived fragrance products, and the ensuing problems associated with such exposure, fragrances derived from flowers and plants were used for millennia to soothe and heal. Historically, herbal medicine has been used for the purposes of "clearing, consoling, quieting, uplifting, and settling the mind and the emotions." Through his work in homeopathy during the early 1900s, Edward Bach, MD, developed a specialized branch of herbal medicine using only the flowers, which are the highly potent seed-bearing part of a plant. Dr. Bach did not offer any scientific explanation of how the flower remedies worked, and in fact, was wary of the trends in scientific theories. He believed it was necessary to first improve a patient's emotional state in order to bring about physical well being, and by careful observation he developed what is now commonly referred to as the Bach Flower Remedies. (4)

Aromas Influence Body and Mind

The fragrance of essential oils are claimed to enhance everything from emotional state to lifespan. Throughout history aromatic oils have been used for their power to influence emotions and states of mind. This is the basis for which oils have been used for centuries as incense for religious and ritualistic purposes. (5)

Upon inhalation of a fragrance, the odor molecules travel up the nose where they are captured by the olfactory membrane. Each odor molecule fits into specific receptor cell lining the olfactory epithelium. There are hundreds of millions of nerve cells and they are each replaced every 28 days. Odor molecules stimulate the lining of nerve cells which trigger electrical impulses to the olfactory bulb, which then transmits impulses to the gustatory center (where the sensation of taste is perceived), the amygdala (where emotional memories are stored), and other parts of the limbic system of the brain. Essential oils can have some very profound physiological and psychological effects because the limbic system is directly connected to those parts of the brain that control heart rate, blood pressure, breathing, stress levels, hormone balance, and memory. (6)

Of the five senses, only our sense of smell is linked directly to the limbic lobe of the brain, our emotional control center. Fear, anxiety, depression, anger, and joy all emanate from this region of the brain. A particular scent or fragrance can evoke memories and emotions before we are even consciously aware of them. Our senses of touch, taste, hearing, and sight, are all routed through the thalamus, which serves as a switchboard for the brain, passing stimuli onto the cerebral cortex and to other parts of the brain. (6)

The limbic lobe, which encompasses a group of brain structures including the hippocampus, can also directly activate the hypothalamus, one of the most important parts of the brain, which serves as our hormonal control center. The hypothalamus is responsible for the production of growth hormones, sex hormones, thyroid hormones, and neurotransmitters such as serotonin. The hypothalamus has earned the designation of "master gland" due to its many important functions. (6)

The limbic lobe and hypothalamus can be directly stimulated through the fragrance and unique molecular structure of essential oils, which can exert a profound effect on the body and mind. Inhalation of essential oils can be used to reduce stress and emotional trauma, and to stimulate the production of hormones from the hypothalamus that can result in increased thyroid hormone responsible for our energy levels, among other things, and growth hormone known as the youth and longevity hormone. (6)

Upon inhaling a particular scent, the odor travels through the nose to the limbic section of the brain that controls stress levels, heart rate, blood pressure and breathing. Fragrance chemicals easily alter the brain's neurochemistry. Dr. Alan Hirsch of the Smell and Taste Treatment Center and Research Foundation in Chicago believes smells can change a mood state faster than anything else. Through the ages we have accumulated much information about the positive effects of essential oils on mood and general well being. Unfortunately, we know very little about the effects of synthetic fragrance on the brain. (6), (7)

In the 1970s, however, there was a classic case of synthetic fragrance causing widespread health problems. The chemical, AETT (acetylethyltetramethyletetralin) was included in numerous personal care products. A series of animal studies showed it to cause significant brain and spinal cord damage, but the United States Food and Drug Administration (FDA) refused to ban the chemical. After years of allowing its distribution in consumer products, the cosmetic industry finally withdrew it. (6)

Essential Oils

Essential oils are components of hundreds of different chemicals that can exert many different effects on the body. This completely prevents pure essential oils from disrupting the body's natural balance or homeostasis. If one constituent exerts too strong an effect, another constituent may block or counteract it, thereby preserving homeostasis. Synthetic chemicals, on the other hand, usually have only one action, which often disrupts the body's natural homeostasis. (6)

Brain Oxygen

Researchers at the Universities of Vienna and Berlin found that sesquiterpenes in the essential oils of sandalwood and frankincense can increase levels of oxygen in the brain as much as 28 percent. An increase in brain oxygen can improve the level of activity in the hypothalamus and limbic systems of the brain, dramatically affecting emotions, learning, and attitude. Increased oxygen in the brain also improves the immune system, hormone balance, and energy levels. In addition to sandalwood and frankincense, high levels of sesquiterpenes are found in melissa, myrrh, and clove oils. (6), (8)

Weight Loss

Essential oils are capable of stimulating the ventromedial nucleus of the hypothalamus, a portion of the brain that regulates our feeling of satiety, or fullness after a meal. In a clinical study conducted by Alan Hirsch, MD, at the Smell and Taste Treatment Center and Research Foundation, essential oils were used to reduce appetite and bring about dramatic results in weight loss involving more than 3,000 participants over a six-month period. The essential oil of peppermint was used on a group of patients previously unsuccessful in any weight loss program. The average weight loss exceeded five pounds each month, and was reported in the Annals of Clinical and Laboratory Science, Vol. 14, Sept/Oct No. 5. (6)

Lavender and Libido

Appetite is not the only thing that essential oils have been successful in stimulating. A second double blind randomized study by Dr. Hirsch documents the ability of certain aromas to enhance libido. The study included 31 males who were exposed to 30 different essential oil aromas. The scents that produced the most excitement in the study, and among the subjects, were a combination of lavender and pumpkin. (6)

Therapeutic Standards

Essential oils are the volatile liquids distilled from plant components including flowers, fruits, seeds, leaves, bark, stems, and roots. The purity of an oil is determined by its chemical constituents which can be affected by any number of variables such as, which part of the plant was used for extracting the oil, geographical region, altitude, climate, soil, growing conditions, harvest method and season, and distillation process.

Approximately 200 types of oils are distilled from which several thousand chemical constituents and aromatic molecules have been identified and registered. The perfume and cosmetic industry uses 98% of the extracted oils. The remaining two percent is used for therapeutic and medicinal applications. (6)

Therapeutic grade essential oils require the preservation of as many of the delicate aromatic compounds as possible. High temperature and pressure, plus contact with chemically reactive metals, such as copper or aluminum, can easily destroy the fragile aromatic chemicals in the volatile liquids. All therapeutic grade and medicinal essential oils should be distilled only in stainless steel cooking chambers at low pressure and low temperature. Agri-chemical pesticides, herbicides, and fertilizers can react with the essential oils during distillation to produce toxic compounds. (6)

Essential oils are among the oldest medicines used by humankind and are beginning to enjoy a renaissance among holistic health consumers. But not everything sold as "essential" oils are pure therapeutic grade products. Most distillation procedures are designed for maximum profit and may use solvents, high temperatures, high pressure, or reactive metal equipment. The main constituents and fragrances of some oils are synthetically produced. They should not be used for therapeutic applications, and may even carry risks. Only the purest quality essential oils should be used for therapeutic purposes. Adulterated or inferior oils may not produce the desired therapeutic results and could possibly be toxic. (6)

Europe has developed a set of standards to evaluate an essential oil based on the chemical profile and principal constituents necessary for a high quality product. These guidelines, known as AFNOR and ISO standards help consumers differentiate between a therapeutic grade essential oil and an inferior product with a similar chemical makeup and fragrance. AFNOR stands for Association French Normalization Organization Regulation. ISO refers to the International Standards Organization, which has adopted AFNOR standards. A product may be Grade A, and of high quality, but if some constituents are too high or too low, it cannot be AFNOR or ISO certified. Two companies in the US have made serious efforts to comply with the European testing standards. They are Flora Research and Young Living Essential Oils. (6)

Synthetic Chemicals Impair Essential Oils

Essential oils are very diverse in their effects and can perform several different functions. They are described as chemically heterogenetic. Synthetic chemicals are quite the opposite having basically just one action. Our pervasive exposure to perfumes and petroleum based synthetic chemicals in cosmetics and personal care products may interfere with some individuals' ability to fully benefit from using essential oils, and may even cause allergic reaction in sensitive individuals. (6), (8)

When considering daily use of essential oils for health improvement it is strongly advised to avoid personal care products containing ammonium or hydrocarbon-based chemicals. Found in a variety of hand creams, mouthwashes, antiperspirants, after-shave lotions, and hair products, these chemicals include quarternarium 1-29 and polyquarternarium 1-14. Commonly used benzalkonium chloride can be fatal if ingested. These chemicals can be toxic in small concentrations and may possibly react with essential oils creating by-products of unknown toxicity. Sodium lauryl sulfate, propylene glycol and aluminum salts found in many deodorants should also be avoided. (6)

Additional synthetic preservatives and fragrances to avoid in personal care products include methylene chloride, methyl isobutyl ketone, and methyl ketone. Not only are these chemicals toxic in their own right, but they can react with compounds in natural essential oils, resulting in a severe case of dermatitis, or even septicemia (blood poisoning). (6)


Some products that purport to be "fragrance-free" or "unscented" may still contain fragrance chemicals, which may not be listed as an ingredient on the label. Though it is practically impossible to avoid fragrance chemicals in our culture, and in spite of the fact that a growing number of Americans are showing signs of chemical sensitivity, there is very little regulation or monitoring. Fragrance ingredients are not listed on product labels. By claiming fragrance formulations are trade secrets, industry is not required to disclose the compounds to anyone, not even to governmental regulatory agencies who are supposed to protect the public from toxic substances. When an individual experiences an adverse effect from fragrance, it is nearly impossible to pinpoint the specific ingredient responsible. (1)

The Material Safety Data Sheet (MSDS) on many fragrance chemicals clearly state they have not been thoroughly tested, however, no fragranced product carries a warning label. Any material may be used as a fragrance with only a few substances prohibited. The individual components included in a fragrance do not have to be listed along with product ingredients. The only requirement is the word "fragrance" must appear on the label. The FDA now has in place a program to report adverse reactions to cosmetics and there has been an increase in the number of reported adverse reactions to fragrance chemicals. (9)

Reporting Adverse Events

Consumers who believe they have suffered an adverse reaction to fragrance or other chemicals in a consumer product should report their experience to the FDA by calling their local FDA office, or 800-535-4555 (non-emergency), or 301-443-1240 (emergency), or 888-463-6332 for product information.


(1.) Bridges, B, "Fragrance Products Information Network," N.E.E.D.S. newsletter (1-800-634-1380), Nov 2003.

(2.) Williams, RM, "Cosmetic Chemicals and Safer Alternatives," TLfDP, #247/248, Feb/Mar 2004.

(3.) Coleman, J, PhD, "Cosmetics and fragrance products pose high risk for breast cancer and other illness,"

(4.) Bach, E, MD, The Bach Flower Remedies, Keats Pub., Inc., CT, 1997.

(5.) Lawless, J, The Encyclopaedia of Essential Oils, Barnes & Noble, Inc., 1995.

(6.) The People's Desk Reference for Essential Oils, Essential Science Pub., 1999.

(7.) Heuberger, E, "Effects of Chiral Fragrances on Human Autonomic Nervous System Parameters and Self-Evaluation," Chemical Senses, 26:281-292, Oxford Press, 2001.

(8.) Higley, C&A, Reference Guide for Essential Oils, Abundant Health, KS, 1998.

(9.) Bridges, B, "Fragrance by Design," Fragranced Products Information Network,, Nov. 30, 2003.

by Rose Marie Williams, MA

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