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Study of lavender oil (Silexan) in patients with mild to moderate major depressive disorder comparing its effectiveness to placebo

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study examines the use of Silexan, a lavender oil medication, in people with Major Depressive Disorder of mild to moderate severity. The study will evaluate whether taking a daily 80 mg soft capsule of Silexan works better than a placebo in reducing depression symptoms.

The purpose of this research is to determine if Silexan is effective and safe for treating mild to moderate depression. During the study, participants will take either Silexan or a placebo capsule once daily for 8 weeks. The depression symptoms will be monitored throughout the study period using various assessment tools that measure the severity of depression and how it affects daily life.

The study will track any changes in depression symptoms and monitor the overall safety of the treatment. Researchers will observe how participants respond to the medication, including whether their depression symptoms improve or if they achieve remission (very low levels of depression symptoms). They will also keep track of any side effects that may occur during the treatment period.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    You will undergo an evaluation to confirm your diagnosis of mild to moderate major depressive disorder

    Your doctor will verify that you meet the required criteria, including a Montgomery-Åsberg Depression Rating Scale (MADRS) score between 17 and 30 points

    A physical examination, vital signs check, heart test (ECG), and laboratory tests will be performed

  2. Step 2

    Treatment assignment

    You will be randomly assigned to receive either Silexan 80 mg or a placebo

    The medication will be in the form of soft capsules for oral use

    You will need to take one capsule daily

  3. Step 3

    Treatment period

    The treatment period will last for 8 weeks

    During this time, you will continue taking your assigned medication daily

    Your depression symptoms will be monitored using various assessment tools

    Regular safety assessments will be conducted, including physical examinations and monitoring of any side effects

  4. Step 4

    Final evaluation

    At the end of week 8, a final assessment will be conducted

    Your doctor will evaluate changes in your depression symptoms using the MADRS scale

    Additional evaluations will include your overall clinical condition and daily functioning

    Final safety assessments will be performed, including physical examination and laboratory tests

Who can join the trial?

7 criteria

  • Must be at least 18 years old
  • Must have been diagnosed with depression (mild to moderate) that has lasted for at least 2 weeks but not more than 1 year
  • Must score between 17 and 30 points on the depression rating scale (MADRS - a tool doctors use to measure depression severity)
  • Must be receiving treatment as an outpatient (not staying in hospital) from a general doctor or specialist
  • Must have a Body Mass Index (BMI) between 18 and 35 (BMI is a measure that uses your height and weight to determine if you are at a healthy weight)
  • Must provide written consent to participate in the study
  • Must be willing and able to follow doctor's instructions and complete all required self-assessment questionnaires

Who cannot join the trial?

15 criteria

  • History of severe depression or current severe depression symptoms
  • Age below 18 or above 65 years
  • Pregnant or breastfeeding women
  • Current use of antidepressant medications
  • History of suicidal thoughts or attempts
  • Presence of other serious mental health conditions (such as bipolar disorder or schizophrenia)
  • Substance abuse or dependency within the past 6 months
  • Serious medical conditions that could affect depression symptoms
  • Participation in other clinical trials within the past 30 days
  • Known allergies to the study medication or its components
  • Inability to follow study procedures or attend scheduled visits
  • Use of medications that could interact with the study drug
  • History of non-response to depression treatments
  • Unstable medical conditions requiring frequent medication changes
  • Severe liver or kidney problems that could affect drug metabolism
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Investigated drugs

  • Silexan

    (also known as WS 1265) is a lavender oil preparation used to treat mild to moderate major depressive disorder (MDD). It is a natural medicine derived from lavender that has shown potential antidepressant properties. The medication is taken orally once daily and works to help reduce symptoms of depression, including changes in mood, sleep patterns, and overall mental well-being.

  • Placebo

    is an inactive substance that looks identical to the active medication but contains no active ingredients. It is used as a control to measure the effectiveness of the active treatment.

What is already known about the treatment

Silexan – A specialized lavender oil preparation (WS 1265) administered orally in capsule form at a dosage of 80 mg per day. This investigational medication is being studied for the treatment of mild to moderate major depressive disorder (MDD) as a potential alternative to conventional antidepressants. Silexan belongs to the class of natural compounds derived from lavender (Lavandula angustifolia) and works through modulation of several neurotransmitter systems in the brain, though its exact molecular mechanism in treating depression is still under investigation in clinical trials. The medication represents a novel approach to depression treatment, combining the traditional use of lavender with modern pharmaceutical standards and clinical research methodology.

Investigated diseases

Major Depressive Disorder (MDD) - A mental health condition characterized by persistent feelings of sadness, loss of interest in activities, and decreased mood that significantly affects daily life. The condition involves changes in emotions, thoughts, and behaviors that can persist for weeks or months. People with MDD often experience changes in sleep patterns, appetite, energy levels, and difficulty concentrating. MDD can range from mild to moderate to severe, with symptoms varying among individuals. The condition affects both psychological and physical well-being, impacting a person's ability to function in work, social, and personal settings.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-521744-37-00Protocol codeD.01.01.3.06Estimated enrolment500 patientsSponsorDr. Willmar Schwabe GmbH & Co. KG

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