The increase in urinary serotonin and decrease in salivary cortisol concentrations following direct inhalations of...

Area of Science:

• Neuroscience
• Psychology
• Integrative Medicine

Background:

• Exogenous serotonin increases vary in effectiveness.
• Urinary serotonin correlates with cerebrospinal fluid levels, suggesting the olfactory system as a potential pathway for rapid serotonin elevation.
• Previous research indicated parasympathetic activation via essential oil inhalers.

Purpose of the Study:

• To investigate the impact of essential oil inhaler (AromaStick® Balance) on urine serotonin and saliva cortisol excretion.
• To test the efficacy of essential oil application to the nose using different inhalation protocols and control conditions.

Main Methods:

• Two experiments were conducted with healthy individuals (n=8 in pilot, n=80 in main study).
• Participants used a specially designed essential oil inhaler with varying inhalation protocols and control conditions.
• Urine serotonin and saliva cortisol levels were measured post-inhalation.

Main Results:

• Serotonin excretion increased significantly after six inhalations in the pilot study (Cohen's d=0.7).
• Essential oil inhalations were superior to control conditions in the main study, increasing serotonin (0.6
• Cortisol levels significantly decreased after three inhalations (d=0.9).

Conclusions:

• Direct olfactory system delivery of essential oil scents via short, deep inhalations enhances serotonin release.
• Essential oil inhalations led to a significant reduction in cortisol levels.
• This method offers a potential non-invasive approach for mood regulation in both sexes.