An interventional study of Astaxanthin Oral Capsule and Olive Oil Placebo in Healthy Aging, sponsored by University of North Alabama. Completed at 1 site in United States. Open to participants aged 60 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by University of North Alabama · Not applicable, Interventional, and Basic science
This study evaluated whether astaxanthin supplementation affects the body's ability to use fat for energy, cognitive performance, and physical function in healthy older adults. In this randomized, double-blind, placebo-controlled crossover trial, participants received both astaxanthin and a placebo during separate study periods. Neither the participants nor the researchers conducting the assessments knew which treatment participants were receiving during each period. Assessments were used to compare outcomes between the astaxanthin and placebo conditions.
This single-center study evaluated the effects of astaxanthin supplementation on exercise substrate utilization, walking economy, cognitive performance, physical function, and cardiometabolic markers in community-dwelling older adults. The study examined supplementation without an accompanying structured exercise training intervention.
The study used a randomized, double-blind, placebo-controlled, counterbalanced crossover design. Participants received astaxanthin and placebo during two five-week supplementation periods separated by a one-week washout. An independent investigator generated the treatment sequence and coded the supplement bottles to maintain blinding. Astaxanthin capsules provided 12 milligrams of astaxanthin in olive oil, while matched placebo capsules contained olive oil alone. Participants were instructed to take one capsule daily with a meal containing dietary fat. Adherence was assessed by counting capsules returned at the end of each supplementation period.
Participants attended four laboratory visits: a familiarization visit, a baseline assessment before supplementation, and an assessment following each supplementation period. Familiarization included demonstrations and practice of the cognitive and physical performance tasks to reduce learning effects during subsequent assessments.
Testing visits were conducted at approximately the same time of day for each participant. Participants arrived after an overnight fast of at least eight hours and were instructed to avoid alcohol, caffeine, and strenuous exercise for 24 hours before testing. A 24-hour dietary recall was collected during familiarization, and participants were asked to replicate that intake on the day before subsequent testing visits.
Metabolic assessments used indirect calorimetry during a progressive submaximal treadmill walking protocol. Participants completed four stages lasting four minutes each, at speeds of 3.2, 4.0, 4.8, and 5.6 kilometers per hour, with the treadmill incline maintained at 1 percent. Oxygen consumption and carbon dioxide production were measured to characterize substrate utilization using the respiratory exchange ratio. Walking economy was calculated as oxygen consumption per unit distance. Heart rate and perceived exertion were recorded at the end of each stage. Participants wore a safety harness for fall prevention without body-weight support.
Following approximately ten minutes of passive recovery, participants completed computerized cognitive assessments and physical function testing. A three-minute incongruent Flanker task assessed inhibitory control, and a five-minute task-switching test assessed cognitive flexibility. Cognitive performance was characterized using reaction time, response speed, and correct responses per second.
Physical function was assessed using the Timed Up and Go test and handgrip dynamometry. The Timed Up and Go test measured the time required to stand from a chair, walk three meters, turn, return, and sit down. Handgrip testing included three maximal efforts per hand, alternating sides with recovery between attempts. The highest recorded value was used to characterize maximal grip strength.
Fasting capillary blood samples were collected by finger prick for lipid panel assessment using a point-of-care analyzer. Measurements included total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, and derived lipid indices.
Within-participant comparisons between astaxanthin and placebo were used to evaluate supplementation effects. Analyses of treadmill outcomes also considered walking speed and interactions between supplementation condition and walking speed.
University of North Alabama is the lead sponsor of 4 studies on the registry; none are open to participants now.
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Exclusion Criteria:
Participants received one capsule containing 12 mg of astaxanthin in olive oil daily for five weeks
Dietary Supplement: Astaxanthin Oral Capsule
Participants received one matched placebo capsule containing olive oil only daily for five weeks
Dietary Supplement: Olive Oil Placebo
Astaxanthin was administered orally at a dose of 12 mg per day as one capsule containing astaxanthin in olive oil. Participants took one capsule daily with a meal containing dietary fat for five weeks. Capsules were supplied by AstaReal, Inc.
Also known as: Astaxanthin
The placebo was administered orally as one matched capsule containing olive oil without astaxanthin. Participants took one capsule daily with a meal containing dietary fat for five weeks. Placebo capsules were supplied by AstaReal, Inc.
Respiratory Exchange Ratio During Submaximal Walking
Respiratory exchange ratio, calculated as carbon dioxide production divided by oxygen consumption, measured by indirect calorimetry during treadmill walking at 3.2, 4.0, 4.8, and 5.6 kilometers per hour at a 1 percent incline. Values were averaged over the final minute of each stage.
Time frame: Baseline and At the end of each five-week supplementation period.
Incongruent Flanker Task Reaction Time
Reaction time, expressed in milliseconds, during a three-minute computerized incongruent Flanker task. Participants identified the direction of a central arrow while ignoring surrounding arrows. Shorter reaction times indicate faster responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Timed Up and Go Completion Time
Time, expressed in seconds, required to rise from a chair, walk three meters, turn, return to the chair, and sit down during the Timed Up and Go test. One timed trial was performed at each assessment. Shorter completion times indicate better functional mobility.
Time frame: Baseline and At the end of each five-week supplementation period.
Incongruent Flanker Task Response Speed
Response speed, calculated as the reciprocal of reaction time, during a three-minute computerized incongruent Flanker task. Participants identified the direction of a central arrow while ignoring surrounding arrows. Higher values indicate faster responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Incongruent Flanker Task Correct Response Rate
Rate of correct responses, expressed as correct responses per second, during a three-minute computerized incongruent Flanker task. Participants identified the direction of a central arrow while ignoring surrounding arrows. Higher values indicate a greater rate of correct responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Task-Switching Reaction Time
Reaction time, expressed in milliseconds, during a five-minute computerized task-switching test. Participants selected responses according to the color and numerical characteristics of displayed numbers. Shorter reaction times indicate faster responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Maximal Handgrip Strength
Maximal handgrip strength, expressed in kilograms, measured using a hydraulic hand dynamometer. Participants performed three maximal efforts per hand, alternating sides with at least 30 seconds of recovery between attempts. The highest value recorded from either hand was used for analysis. Higher values indicate greater grip strength.
Time frame: Baseline and At the end of each five-week supplementation period.
Oxygen Cost of Walking
Oxygen cost per unit distance, expressed in milliliters of oxygen per kilogram of body mass per meter walked, assessed by indirect calorimetry during treadmill walking at 3.2, 4.0, 4.8, and 5.6 kilometers per hour at a 1 percent incline. Lower values indicate better walking economy.
Time frame: Baseline and At the end of each five-week supplementation period.
Fasting Total Cholesterol Concentration
Total cholesterol concentration in fasting capillary blood collected by finger prick and analyzed using a Cholestech LDX analyzer. Results are expressed in milligrams per deciliter.
Time frame: Baseline and At the end of each five-week supplementation period.
Fasting High-Density Lipoprotein Cholesterol Concentration
High-density lipoprotein cholesterol concentration in fasting capillary blood assessed using a Cholestech LDX analyzer. Results are expressed in milligrams per deciliter.
Time frame: Baseline and At the end of each five-week supplementation period.
Fasting Low-Density Lipoprotein Cholesterol Concentration
Low-density lipoprotein cholesterol concentration obtained from fasting capillary blood lipid panel analysis using a Cholestech LDX analyzer. Results are expressed in milligrams per deciliter.
Time frame: Baseline and At the end of each five-week supplementation period.
Fasting Triglyceride Concentration
Triglyceride concentration in fasting capillary blood assessed using a Cholestech LDX analyzer. Results are expressed in milligrams per deciliter.
Time frame: Baseline and At the end of each five-week supplementation period.
Task-Switching Response Speed
Response speed, calculated as the reciprocal of reaction time, during a five-minute computerized task-switching test. Participants selected responses according to the color and numerical characteristics of displayed numbers. Higher values indicate faster responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Task-Switching Correct Response Rate
Rate of correct responses, expressed as correct responses per second, during a five-minute computerized task-switching test. Participants selected responses according to the color and numerical characteristics of displayed numbers. Higher values indicate a greater rate of correct responses.
Time frame: Baseline and At the end of each five-week supplementation period.
Plan to share: No — Individual participant data will not be shared. Findings will be disseminated through scientific publications and presentations using aggregate results.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Astaxanthine
University of North Alabama