Supporting the Body’s Stress Response with Evidence-Based Aromatherapy

The HPA axis is the body’s main way of handling stress. It releases the hormone cortisol to help us deal with challenges. Short-term cortisol is helpful, but if it stays high for too long, it can harm our health by causing anxiety, tiredness, and a weaker immune system. Studies show that inhaling certain essential oils can help calm the HPA axis and lower cortisol, helping to reduce stress and support a better mood and psychological resilience. This means that aromatherapy can help our bodies handle stress in a healthier way.

The Science

The hypothalamic–pituitary–adrenal (HPA) axis is the body’s main hormonal stress-response system, responsible for releasing cortisol when we encounter stress. While cortisol is essential for short-term adaptation, chronic elevation, caused by ongoing stress, can disrupt metabolism, immune function, mood, and overall health [6][1]. Essential oils, particularly when inhaled, have been shown to help regulate the HPA axis by reducing the release of cortisol. This effect is linked to specific chemical constituents in essential oils that act on the brain’s stress pathways and neurotransmitter systems [2][3][7]. By targeting the HPA axis, essential oils can help restore balance to the body’s stress response, leading to reduced anxiety, improved mood, and better resilience against the negative effects of chronic stress. This report explains the biological mechanisms and research evidence showing that essential oils can lower stress hormone levels and promote emotional well-being through their action on the HPA axis [6][2].

What Is the HPA Axis?

The Hypothalamic–Pituitary–Adrenal (HPA) axis is a central part of the body’s stress response system, a communication network between three major glands:

  • Hypothalamus: Detects stress and releases corticotropin-releasing hormone (CRH).
  • Pituitary Gland: Receives CRH and releases adrenocorticotropic hormone (ACTH).
  • Adrenal Glands: Receive ACTH and release cortisol, the body’s primary stress hormone [1].

How it works: When you encounter stress, the hypothalamus releases CRH, which tells the pituitary gland to release ACTH. ACTH then signals the adrenal glands to release cortisol. Cortisol helps the body respond to stress by increasing alertness, blood sugar, and energy. Once enough cortisol is present, it signals the brain to slow down this response, a feedback loop that maintains balance[1][2][8].

Why Is Cortisol relevant to stress?

Cortisol is essential for survival, as it mobilises energy and helps the body respond to challenges [2]. However, when cortisol is elevated for long periods (chronic stress), it can cause:

  • Metabolic problems: Increased blood sugar, weight gain, and risk of diabetes.
  • Cardiovascular strain: Raised blood pressure and increased heart disease risk.
  • Immune suppression: Reduced ability to fight infections.
  • Mood and cognitive issues: Anxiety, depression, memory loss, and brain fog.
  • Fatigue and burnout: Disrupted daily cortisol rhythms and HPA axis exhaustion [2][3].

The HPA Axis vs. the Autonomic Nervous System (ANS)

While both systems respond to stress, they work differently:

  • ANS: Acts within seconds; controls immediate, automatic responses (like heart rate and breathing) through its sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) branches.
  • HPA Axis: Acts over minutes to hours; manages longer-term, hormonal responses to stress, primarily through cortisol release [1][8].

Why both matter: The ANS handles rapid adjustments, while the HPA axis ensures sustained adaptation. Chronic stress can keep both systems overactive, leading to health problems. The hypothalamus is a key link, regulating both systems and integrating emotional and physical responses to stress [1][8].

How Essential Oils Influence the HPA Axis

Research shows that essential oils can help regulate the HPA axis and reduce the release of cortisol. This effect is closely linked to their major chemical constituents, which act on brain pathways and neurotransmitter systems involved in stress regulation [3][7][9].

Therapeutic Mechanisms

Olfactory Pathway: Inhaled essential oil molecules stimulate the olfactory system and limbic brain regions, including the hypothalamus, which directly regulates the HPA axis and cortisol release [3][7].

Neurotransmitter Modulation: Constituents such as linalool, geraniol, β-caryophyllene, limonene, and cedrol can enhance calming neurotransmitters (like GABA and serotonin), inhibiting the release of stress hormones [7][9].

Bloodstream Effects: Some components, when absorbed through the lungs or skin, can enter the bloodstream and interact with hormone receptors, further supporting HPA axis balance [7][9].

Relaxation Formula Essential Oils and Their Constituents: Impact on the HPA Axis

The following essential oils and their key constituents have demonstrated effects on the HPA axis and cortisol regulation:

Pelargonium Graveolens Oil (Geranium): Key constituents: Citronellol, geraniol, linalool
HPA axis impact: Shown to lower glucocorticoid (cortisol) levels and modulate stress-related signalling pathways, supporting stress resilience through hormonal regulation[7].

Pogostemon Cablin Oil (Patchouli): Key constituents: Patchoulol, α-bulnesene, pogostol
HPA axis impact: Contains sedative constituents and may reduce ACTH and cortisol levels, supporting the negative feedback loop of the axis [9].

Cedrus Atlantica Bark Oil (Cedarwood Atlas): Key constituents: Cedrol, α-cedrene, himachalene
HPA axis impact: Cedrol is associated with calming effects and may contribute to the reduction of stress hormone output [5].

Citrus Paradisi Peel Oil (Grapefruit): Key constituent: Limonene
HPA axis impact: Limonene is linked to mood enhancement and mild anxiolytic effects, and has been shown to support HPA axis balance by reducing excessive cortisol release [7].

Cymbopogon Martini Oil (Palmarosa): Key constituents: Geraniol, linalool
HPA axis impact: These constituents are associated with calming and anti-anxiety effects, likely through GABAergic and serotonergic modulation, which helps regulate cortisol [9].

Cananga Odorata Flower Oil (Ylang Ylang): Key constituents: Linalool, β-caryophyllene, benzyl benzoate
HPA axis impact: Linalool and β-caryophyllene have been shown to decrease plasma cortisol and support HPA axis regulation through serotonin and dopamine pathways [9].

How Essential Oils Interact

Inhaled or absorbed essential oil constituents activate the limbic system, sending calming signals to the hypothalamus and modulating neurotransmitters. This reduces CRH, ACTH, and ultimately cortisol, helping to restore balance to the stress response and support HPA axis health [3][7[]9].

Practical Benefits

By helping to regulate the HPA axis and lower stress hormones, essential oils may:

  • Reduce feelings of anxiety and overwhelm
  • Improve mood and emotional balance
  • Support restful sleep · Protect against the negative effects of chronic stress [3][7][9]

Conclusion

In conclusion, this report provides the scientific basis for the relaxation essential oil formula and demonstrates its efficacy in treating stress. By targeting the HPA axis, the body’s primary hormonal stress-response system, essential oils rich in linalool, geraniol, β-caryophyllene, limonene, and cedrol have been shown to help regulate cortisol levels and restore balance. Through these well-established neuroendocrine pathways, the relaxation blend supports both emotional and physical well-being, offering an evidence-based approach to managing and alleviating the negative effects of chronic stress [6][3][7][9].

Explore The Relaxing Blend CollectionOur 90-Day Money-Back Guarantee

The HPA Axis & Stress: How Essential Oils Help Regulate Cortisol

References
  1. Cleveland Clinic: Hypothalamic-Pituitary-Adrenal (HPA) Axis
  2. Understanding Cortisol: The Hormone's Role in Stress Response and Health
  3. Essential Oils for Stress Relief | The School of Aromatic Studies
  4. Protective effects of Pelargonium graveolens (geranium) oil against ...
  5. Comparison on Phytochemical Constituents in The Patchouli Oil of In Vitro And Ex Vitro Pogostemon cablin Leaves
  6. Hypothalamic–pituitary–adrenal axis - Wikipedia
  7. 2-Minute Neuroscience: HPA Axis - YouTube
  8. Bouyahya A, Chamkhi I, Balahbib A, et al. Chemical Composition, Antioxidant and Antibacterial Activities and In Silico Study of Cedrus atlantica, Chenopodium ambrosioides and Eucalyptus camaldulensis Essential Oils. Molecules. 2023;28(7):2997.