7+ Ways Fragrance Changes Your Hormones And Immune System (Must Read For Chemically Sensitive People)

7+ Ways Fragrance Changes Your Immune System And Hormones (Must Read For Chemically Sensitive People)

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Fragrances are slow toxins which can disrupt the endocrine-immune-neural axis possibly causing the unprecedented rates of diabetes, cancer, neural ailments, teratogenicity, and transgender instances. R

We’ve already discussed how parts in fragrance can act as haptens and cause allergic sensitization (in this hapten post and this fragrance post), so in today’s post we will be discussing more mechanisms as to how fragrance can disrupt your immune system.


  1. Basics Of Common Fragrances

  2. How Do Olfactory Receptors Work?

  3. What Does Fragrance Do?

  4. Possible Benefits Of Fragrance

  5. What Should You Do About Fragrance?

  6. Mechanism Of Action

Basics Of Common Fragrances

Most of our hazardous pollutants are actually chemicals from indoors, fragranced consumer products (ie air fresheners, cleaning products, laundry supplies, and personal care products) being one of the most common. R

These fragranced consumer products emit dozens of different volatile compounds, such as terpenes (limonene, alpha-pinene, beta-pinene, etc) that are primary pollutants, and can react with ozone to generate secondary pollutants, such as formaldehyde and acetaldehyde. R

Fragranced consumer products can be found in: R

  • Air fresheners and deodorizers

  • Cleaning supplies

  • Fragrance/Perfume

  • Household products

  • Laundry products

  • Personal care products

Health effects have shown to cause: R

  • Asthma attacks

  • Cardiovascular problems

  • Cognitive problems

  • Gastrointestinal problems

  • Immune system problems

  • Migraine headaches

  • Mucosal symptoms

  • Musculoskeletal problems

  • Neurological problems

  • Respiratory problems

  • Skin problems

How Do Olfactory Receptors Work?

We have olfactory receptors all over the body, not just the nose. R

Smells activate olfactory receptors via increase in Cyclic Adenosine Monophosphate (c-AMP) and Inositol Triphosphate (IP3), which thus can control thousands of genes. R

Fragrances can activate olfactory receptors by smell, nose and mouth, and thereafter, enter the blood stream and thus the brain (due to fragrance being lipohilic). R

Fragrance can influence you beneficially (if your immune system is in good working order), detrimentally (if your immune system has been primed to react), or have no effect at all.

What Does Fragrance Do?

1. Endocrine Disruption




Pthalates can be used as fragrance due to their unique structure and ability to have a long lingering smell (they form bonds with surfaces due to its lipophilic structure). R

Pthalates are weak endocrine disruptors and androgen blocking chemicals, which means that when absorbed into the body phthalates can either mimic or block female hormones (such as estrogen), or in males, suppress the hormones involved in male sexual development (see more in post on estrogenics). R

Fragrance has also shown in women to increase Dehydroepiandrosterone (DHEA) level in saliva and skin, thus causing facial and forearm bloating. R

2. Asthma, Allergies And Infections

Pthalates are also able to skew the immune system to from a TH1 response to a TH2 response (mainly IgG1 but also IgE), thus blunting the ability to fight off certain infections and increasing the risk for allergies. R R

For example, pthalates are able to increase the risk of asthma in children. R

This skewing of TH1 responses are possible from other types of fragrances as well, not just pthalates. R

Even common fragrances can cause immune sensitization (commonly seen as skin problems). R R

For example, some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. R

3. Stress And Autoimmunity




Stress causes the release of numerous immune mediators that can prime the immune system via Cortisol, Substance P (SP), T Helper Cells (TH1, TH2, etc), Mast Cells, Prostaglandin D2 (PGD2), Histamine, and Leukotriene B4 (LTB4). R

When combined with stress, fragrance is able to change the Hypothalamic–Pituitary–Adrenal (HPA) axis, causing dysregulation of Noradrenergic, Serotonergic, Cholinergic, Gamma-Aminobutyric Acid (GABA)-ergic and Glutamatergic neurotransmitter systems. R

Having autoantibodies are a common sign of autoimmunity. R

For example, people with Anorexia Nervosa (AN) and Bulimia Nervosa (BN) have demonstrated autoantibodies reacting with Alpha-Melanocyte-Stimulating Hormone (alpha-MSH) or Adrenocorticotropic Hormone (ACTH), which are melanocortin peptides involved in appetite control and the stress response.R

4. Appetite Stimulation And Suppression

Apart from influencing diseases like anorexia and bulimia, fragrance may cause appetite stimulation as well.

For example, linalool and limonene inhalation has shown to change Neuropeptide Y (NPY, an appetite regulator) levels, more specifcally linalool increased NPY, while limonene decreased serum NPY levels. R

5. Adrenaline And Blood Pressure

Fragrances can change adrenaline levels and thus blood pressure – some examples: ↓ rose oil, ↓ patchouli oil, and ↑ pepper oil. R

6. Transgender And Gender Dysphoria

Fragrance may influence the rise in transgender instances and gender dysphoria. R

Endocrine disruptors such as pthalates and Polychlorinated Biphenyls (PCB) have shown to profoundly impair the sexual development of the female hypothalamus during development. R

These endocrine disruptors have also shown to increase fetal levels of Testosterone (T) during pregnancy, thus leading to increased risk of gender dysphoria. R

7. Sexual Attraction


We are attracted to someone else’s body odor based on the smell of their immune system.

Major Histocompatibility Complex (MHC) genes play a crucial role in immune recognition. R

Having differences in your MHC genes can make you sexually attracted to someone else’s scent. R

Also, people that share the same type of Human Leucocyte Antigen (HLA) have a similar preference for perfume ingredients that are used to amplify someones natural body odor. R

Possible Benefits Of Fragrance

There are clear benefits to some specific fragrances, but I will elaborate on those possibly in a separate post.

For now I will focus on 3 benefits.

1. Sleep

Some fragrances from essential oils may help with sleep. R

For example, lavender fragrance has shown to improve the quality of sleep in postpartum women after 8 weeks of use. R

2. Attractiveness

Fragrance may increase mate attraction through various mechanisms, such as increasing self-confidence or seducing a biologically incompatible mate. R

3. Cancer

Some fragrances may be beneficial for fighting cancer. R

For example, linalool can stimulate IFN-γ, IL-13, IL-2, IL-21, IL-21R, IL-4, IL-6sR and TNF-α secretion, which may be beneficial for stimulating the immune system to combat caner. R

What Should You Do About Fragrance?


See other post on hapten tolerance.

Mechanism Of Action


  • Increases IFN-γ R

  • Increases IgE R

  • Increases IgG1 R

  • Increases IL-2 R

  • Increases IL-4 R

  • Increases IL-6sR R

  • Increases IL-13 R

  • Increases IL-21 R

  • Increases IL-21R R

  • Increases NPY R

  • Increases TNF-α R

  • Reduces PGD2 (in mast cells) R