An interventional study of Astaxanthin Oral Capsule and Matched Placebo (Capsules) in Asthma (Diagnosis), Airway Inflammation and Airway Hyperresponsiveness, sponsored by Middlesex University. Recruiting at 1 site in United Kingdom. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-02.
Sponsored by Middlesex University · Not applicable, Interventional, and Treatment
This study will test whether astaxanthin, a naturally occurring antioxidant supplement, can improve lung function, reduce airway inflammation, and improve asthma control in adults with mild-to-moderate asthma. Participants will receive astaxanthin and placebo in random order in a double-blind crossover design. Each treatment period lasts 4 weeks and is separated by a 3-week washout period. The study also measures indoor and personal air pollution exposure to examine whether pollution influences asthma symptoms, airway responsiveness, and response to treatment. Exploratory thoracic bioelectrical impedance spectroscopy will be assessed alongside standard respiratory tests.
This is a randomized, double-blind, placebo-controlled, 2-sequence, 2-period crossover trial in 25 non-smoking, non-vaping adults aged 18 to 59 years with mild-to-moderate asthma or asthma-like symptoms confirmed at screening. Participants will be allocated 1:1 to one of two treatment sequences: astaxanthin followed by placebo, or placebo followed by astaxanthin. Each intervention period lasts 4 weeks and is separated by a 3-week washout. Astaxanthin will be given orally at a total dose of 12 mg/day as three 4 mg capsules taken with the participant's largest meal; placebo capsules will be matched. Outcome assessments include FeNO, spirometry, impulse oscillometry, body plethysmography, hypertonic saline challenge with induced sputum collection, home peak expiratory flow monitoring, questionnaires, and exploratory thoracic bioelectrical impedance spectroscopy. Indoor and personal air pollution exposures will be measured throughout the study to evaluate whether pollution modifies respiratory outcomes and treatment response.
Confirmed clinical diagnosis of mild-to-moderate asthma, defined as:
(those with suspected Asthma will be invited to a familiarisation and eligibility session where they will have clinical investigations to assess for asthma and thus be included or excluded)
Exclusion Criteria:
Participants receive astaxanthin 12 mg/day orally for 4 weeks, followed by a 3-week washout, then matched placebo orally for 4 weeks.
Dietary Supplement: Astaxanthin Oral Capsule · Dietary Supplement: Matched Placebo (Capsules)
Participants receive matched placebo orally for 4 weeks, followed by a 3-week washout, then astaxanthin 12 mg/day orally for 4 weeks.
Dietary Supplement: Astaxanthin Oral Capsule · Dietary Supplement: Matched Placebo (Capsules)
Natural astaxanthin derived primarily from Haematococcus pluvialis, administered orally as three 4 mg capsules daily (total 12 mg/day) with the participant's largest meal for 4
Matched placebo capsules administered orally once daily as three capsules with the participant's largest meal for 4 weeks.
Change in Forced Expiratory Volume in 1 Second (FEV1)
FEV1 measured by spirometry using a calibrated Medisoft BodyBox system. Comparison is within-participant change after astaxanthin versus placebo.
Time frame: Measured at period-specific baseline and restablishment of baseline after washout period and end of each 4-week treatment period
Change in Fractional Exhaled Nitric Oxide (FeNO)
FeNO measured in parts per billion using the NIOX VERO analyser. Comparison is within-participant change after astaxanthin versus placebo.
Time frame: Measured at period-specific baseline and restablishment of baseline after washout period and end of each 4-week treatment period
Change in Airway Hyperresponsiveness During Hypertonic Saline Challenge
Hypertonic saline challenge response quantified using the dose response slope
Time frame: Measured at period-specific baseline and end of each 4-week treatment period
Change in Impulse Oscillometry Resistance at 5 Hz (R5)
R5 measured during tidal breathing using the PulmoScan system
Time frame: Baseline, end of phase 1, post washout and end of phase 2
Change in Impulse Oscillometry Area of Reactance (AX)
AX measured using the PulmoScan system as an index of peripheral airway involvement.
Time frame: Baseline, end of phase 1, post washout and end of phase 2
Change in Asthma Control Questionnaire-6 (ACQ-6) Total Score
Participant-reported asthma control measured using the ACQ-6.
Time frame: Weekly during the 11- to 12-week study period
Change in Asthma Quality of Life Questionnaire (AQLQ) Total Score
Every 2 weeks during the 11- to 12-week study period
Time frame: Participant-reported asthma-related quality of life measured using the AQLQ.
Change in Peak Expiratory Flow Amplitude Percent Mean (PEF APM)
Diurnal variability in peak expiratory flow derived from home morning and evening PEF
Time frame: Twice daily during each treatment period and washout, up to 11 to 12 weeks
Change in Sputum Eosinophil Percentage
Baseline, end of phase 1, post washout period and end of phase 2
Time frame: Induced sputum cellular differential measured after hypertonic saline challenge.
Change in Sputum Interleukin-8 (IL-8) Concentration
Baseline, end of phase 1, post washout and end of phase 2
Time frame: IL-8 measured in processed induced sputum.
Change in Thoracic Bioelectrical Impedance Spectroscopy Phase Angle
Exploratory TBIS measure obtained using the BodyStat Multiscan 500 to assess feasibility and physiological coherence relative to standard respiratory measures
Time frame: Baseline, end of phase 1, post washout and end of phase 2. And supplementary changes during hypertonic saline challenge testing
Plan to share: Undecided
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Middlesex University