An interventional study of Spermidine Supplementation and Dietary Placebo in Mild Cognitive Impairment Due to Alzheimer's Disease and Subjective Cognitive Decline (SCD), sponsored by University Medicine Greifswald. Recruiting at 1 site in Germany. Open to participants aged 55 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-02.
Sponsored by University Medicine Greifswald · Not applicable, Interventional, and Basic science
This clinical trial investigates the effects of spermidine supplementation on sleep quality and sleep-dependent memory consolidation in older adults with Subjective Cognitive Decline (SCD) or Mild Cognitive Impairment (MCI), two populations at increased risk of future cognitive decline and dementia. Impaired sleep has been identified as a modifiable factor contributing to cognitive decline, and interventions targeting sleep architecture could offer therapeutic potential to prevent or slow down this decline.
Spermidine is a naturally occurring polyamine found in foods such as wheat germ and soybeans. It induces autophagy, a cellular degradation and recycling process essential for neuronal maintenance and function. In animal studies, spermidine has been shown to improve memory performance, reduce neuroinflammation, and support mitochondrial health. Preliminary findings from human trials in individuals with SCD or MCI suggest potential cognitive benefits of spermidine, but results are not unequivocal, and the impact on sleep has not been systematically evaluated.
In this randomized, double-blind, placebo-controlled trial, 76 participants aged 55 to 75 years with SCD or MCI will receive either spermidine (6 mg/day) or a placebo for 12 weeks. Sleep will be evaluated using overnight EEG in a controlled laboratory setting, focusing on measures such as slow-wave sleep and sleep spindle activity. Memory performance will be assessed before and after the intervention using standardized neuropsychological testing. Numerical skills will be tested at baseline only to compare SCD and MCI participants with healthy controls.
Blood samples will be collected to quantify metabolic indicators, neurodegeneration-related biomarkers, and autophagy-associated proteins. A control group of 38 cognitively healthy individuals will undergo comparable sleep and cognitive assessments without receiving any supplementation.
The primary objective of the study is to characterize the impact of spermidine on sleep-dependent memory consolidation and to identify associated biological changes relevant to aging and neurodegeneration. The results may inform the development of non-pharmacological strategies aimed at preserving cognitive function in individuals at risk for dementia.
Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI) represent early stages along the continuum of cognitive decline preceding dementia. Individuals with SCD report persistent cognitive complaints despite normal performance on standardized cognitive testing, whereas MCI is characterized by objective cognitive impairment that does not yet interfere substantially with activities of daily living. Both conditions are associated with an elevated risk of progression to Alzheimer's disease and other dementias. Disruption of sleep architecture is increasingly implicated in the pathophysiology of neurodegenerative disorders, and early interventions targeting sleep-related mechanisms could help delay further cognitive decline. This clinical trial evaluates the effects of spermidine supplementation on sleep quality and sleep-dependent memory consolidation in older adults with SCD or MCI.
Following an adaptation night and an initial baseline sleep assessment with overnight electroencephalography (EEG), participants will be randomly assigned to either the spermidine or placebo group. The intervention consists of a daily oral dose of 6 mg spermidine (administered as three 2 mg sachets), continued over a 12-week period. The trial employs a randomized, double-blind, placebo-controlled design. Placebo sachets, identical in appearance and taste, contain only microcrystalline cellulose. After the 12-week supplementation period, participants will return for a second overnight EEG assessment.
A healthy control group (n=38), matched for age and sex, will undergo comparable baseline assessments but will not receive any intervention. These data will provide normative reference values for sleep and cognitive parameters.
The primary objective of the study is to assess the impact of spermidine on sleep architecture, measured via overnight polysomnography, with a specific focus on slow-wave sleep and sleep spindle activity, EEG markers associated with sleep-dependent memory consolidation and known to decline with age and neurodegeneration. Secondary outcomes include changes in memory consolidation (assessed using a battery of cognitive tasks that target declarative, procedural, and visuospatial memory domains), as well as numerical skills (tested via e.g., digit-letter-decision task, Berlin Numeracy Test). Testing occurs before and after each EEG night to evaluate overnight consolidation effects. All participants will wear actigraphs prior to both EEG nights to monitor sleep-wake cycles and physical activity.
Additional biological endpoints will examine changes in circulating neuropeptides, insulin-glucose homeostasis, and autophagy-related biomarkers. Blood samples are collected at each EEG session and two weeks after the start of supplementation. Physiological assessments include measurements of inflammatory markers (e.g., interleukin (IL)-6, tumor necrosis factor (TNF-α), neuroprotective factors (e.g., Neuropeptide Y, eukaryotic translation initiation factor 5A (eIF5A) hypusination), and metabolic indicators (e.g., fasting insulin, glucose, and lipid profiles).
Participants will undergo structural brain imaging using a 3-Tesla MRI scanner to exclude individuals with comorbid neurological conditions (e.g., prior stroke, other neurodegenerative diseases) and to assess brain morphology. Eligibility is determined through standardized pre-screening procedures, including clinical interviews and neuropsychological assessments.
The study includes 76 participants with SCD or MCI, aged 55-75 years, randomly allocated to either the spermidine or placebo group (n=38 per group). The sample size provides adequate statistical power to detect medium-to-large effect sizes, based on previous pilot findings and anticipated attrition rates.
This study aims to investigate the effects of spermidine supplementation on neurophysiological and cognitive outcomes in individuals with early-stage cognitive decline. The results are expected to contribute to the growing body of evidence evaluating spermidine as a safe, nutrition-based strategy for maintaining brain health and cognitive function in the context of aging.
3,872 studies on the registry are indexed under Cognitive Dysfunction; 1,119 are open to participants now.
This study's planned enrollment of 76 is above the median of 64 across 2,794 interventional studies indexed under Cognitive Dysfunction.
Browse Cognitive Dysfunction studies →University Medicine Greifswald is the lead sponsor of 152 studies on the registry; 22 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 2, 2026. See what changed
Inclusion Criteria (SCD participants):
Subjective Cognitive Decline operationalized as:
Inclusion Criteria (MCI patients):
Mild cognitive impairment (MCI) operationalized as:
Exclusion Criteria (SCD and MCI participants):
Inclusion criteria (healthy controls):
Exclusion criteria (healthy controls):
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
baseline comparison, healthy controls are not part of the intervention
Dietary Supplement: Dietary Placebo
Dietary Supplement: Spermidine Supplementation
supplementation of 6 mg Spermidine per day across 3 doses
supplementation of 6 mg Placebo per day across 3 doses (placebo consists of maltodextrin, rice extract microcrystalline cellulose mixture, citric acid (anhydrous), silicon oxide (precipitated, E551))
Effects of spermidine supplementation on sleep quality as measured by electroencephalography (EEG) mean power spectra
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow oscillations (0.5-1 Hz), low delta (1-1.5 Hz), delta (1-4 Hz), theta (4-8 Hz), and beta (15-25 Hz). For the spermidine effect, baseline and follow-up EEG data are compared with each other.
Time frame: baseline, 12-week follow-up
Effects of spermidine supplementation on sleep quality as measured by sleep spindle count assessed from EEG
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow frontal spindle (8-12 Hz), fast parietal spindle (12-15 Hz), and the number of slow frontal and fast parietal discrete spindles are counted. Spindle detection is performed based on an algorithm adopted from previous studies. For the spermidine effect, baseline and follow-up EEG data are compared with each other.
Time frame: baseline, 12-week follow-up
Effects of spermidine supplementation on sleep quality as measured by sleep spindle power assessed from EEG
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow frontal spindle (8-12 Hz), fast parietal spindle (12-15 Hz). Spindle power is analyzed as a further measure of spindle activity. Spindle detection is performed based on an algorithm adopted from previous studies. For the spermidine effect, baseline and follow-up EEG data are compared with each other.
Time frame: baseline, 12-week follow-up
Effects of spermidine supplementation on sleep-related alertness as measured by computer-based task
The alertness task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. It comprises two runs without and two runs with a prior warning tone. For the spermidine effect, baseline and follow-up task performances of SCD and MCI participants are compared with each other. Task performance is measured by speed (in ms) and hit/false or miss.
Time frame: baseline, 12-week follow-up
Effects of spermidine supplementation on sleep-related visual-spatial memory as measured by computer-based task
The visual-spatial memory task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. After an encoding phase consisting of 60 objects (e.g., photo of a band-aid) placed in front of a background (e.g., photo of a treatment room in a doctor's office), a retrieval phase follows directly after encoding in the evening before bedtime, in which 30 randomly selected images from the total of 60 are tested. Participants should memorize the position of the object placed in front of the background and select the correct position by pressing a button. In the next morning, the remaining 30 images are tested in a recall phase. Task performance is measured by speed (in ms) and hit/false or miss. For the spermidine effect, baseline and follow-up task performances of SCD and MCI participants are compared with each other.
Time frame: baseline, 12-week follow-up
Effects of spermidine supplementation on sleep-related verbal memory as measured by computer-based task
The verbal memory task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. After an encoding phase consisting of 44 word pairs, a retrieval phase follows directly after encoding in the evening before bedtime, in which all word pairs are tested in randomized order. The next morning, all word pairs are tested in a recall phase. Task performance is measured by hit/false or miss. For the spermidine effect, baseline and follow-up task performances of SCD and MCI participants are compared with each other.
Time frame: baseline, 12-week follow-up
Differences in autophagy-related blood markers pre and post spermidine intervention in SCD and MCI as measured by polyamine concentration
concentration in nmol / mg Protein assessed via Peripheral Blood Mononuclear Cells (PBMCs)
Time frame: baseline, 2 weeks after baseline, 12-week follow-up
Differences in sleep quality between SCD or MCI and healthy controls (HC) as measured by electroencephalography (EEG) mean power spectra
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow oscillations (0.5-1 Hz), low delta (1-1.5 Hz), delta (1-4 Hz), theta (4-8 Hz), and beta (15-25 Hz). The differences between SCD / MCI and healthy controls are assessed from baseline EEG data.
Time frame: baseline data
Differences in sleep quality between SCD or MCI and healthy controls (HC) as measured by sleep spindle count assessed from EEG
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow frontal spindle (8-12 Hz), fast parietal spindle (12-15 Hz), and the number of slow frontal and fast parietal discrete spindles are counted. Spindle detection is performed based on an algorithm adopted from previous studies. The differences between SCD / MCI and healthy controls are assessed from baseline EEG data.
Time frame: baseline data
Differences in sleep quality between SCD or MCI and healthy controls (HC) as measured by sleep spindle power assessed from EEG
Individual mean power spectra are calculated. Subsequently, the mean power is calculated in the following EEG bands: slow frontal spindle (8-12 Hz), fast parietal spindle (12-15 Hz). Spindle power is analyzed as a further measure of spindle activity. Spindle detection is performed based on an algorithm adopted from previous studies. The differences between SCD / MCI and healthy controls are assessed from baseline EEG data.
Time frame: baseline data
Differences in autophagy-related blood markers pre and post spermidine intervention in SCD or MCI as measured by eIF5A hypusination
assessed via Hypusinated eIF5A levels (Western Blot) from Peripheral Blood Mononuclear Cells (PBMCs)
Time frame: baseline, 2 weeks after baseline, 12-week follow-up
Differences in neuropeptide Y blood levels pre and post spermidine intervention in SCD or MCI
Neuropeptide Y blood levels in pg/ml analyzed from serum blood sample
Time frame: baseline, 12-week follow-up
Differences in sleep-related alertness between SCD or MCI participants and healthy controls as measured by computer-based task
The alertness task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. It comprises two runs without and two runs with a prior warning tone. The differences between SCD / MCI and healthy controls are assessed from baseline task data. Task performance is measured by speed (in ms) and hit/false or miss.
Time frame: baseline
Differences in sleep-related visual-spatial memory between SCD or MCI participants and healthy controls as measured by computer-based task
The visual-spatial memory task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. After an encoding phase consisting of 60 objects (e.g., photo of a band-aid) placed in front of a background (e.g., photo of a treatment room in a doctor's office), a retrieval phase follows directly after encoding in the evening before bedtime, in which 30 randomly selected images from the total of 60 are tested. Participants should memorize the position of the object placed in front of the background and select the correct position by pressing a button. In the next morning, the remaining 30 images are tested in a recall phase. Task performance is measured by speed (in ms) and hit/false or miss. The differences between SCD / MCI and healthy controls are assessed from baseline task data.
Time frame: baseline
Differences in sleep-related verbal memory between SCD or MCI participants and healthy controls as measured by computer-based task
The verbal memory task is trained at adaptation night and assessed at baseline and follow-up before and after sleep. After an encoding phase consisting of 44 word pairs, a retrieval phase follows directly after encoding in the evening before bedtime, in which all word pairs are tested in randomized order. The next morning, all word pairs are tested in a recall phase. Task performance is measured by hit/false or miss. The differences between SCD / MCI and healthy controls are assessed from baseline task data.
Time frame: baseline
Differences in neuropeptide Y blood levels between SCD or MCI and healthy controls
blood levels in pg/ml analyzed from serum blood sample
Time frame: baseline data
Differences in autophagy-related blood markers between SCD or MCI and healthy controls as measured by polyamine concentration
concentration in nmol / mg Protein assessed via Peripheral Blood Mononuclear Cells (PBMCs)
Time frame: baseline data
Differences in autophagy-related blood markers between SCD or MCI and healthy controls as measured by eIF5A hypusination
assessed via Hypusinated eIF5A levels (Western Blot) from Peripheral Blood Mononuclear Cells (PBMCs)
Time frame: baseline data
Differences in numerical skills between SCD or MCI patients and healthy controls as measured by lexical decision task
Participants complete a computer-based lexical decision task, in which a row of six symbols is presented after a fixation cross. Depending on the condition, the test subjects must decide by pressing a key on the keyboard whether the row presented contains a letter (e.g., condition 1) or a digit (e.g., condition 2). Each condition consists of two blocks. After the first block, there is a short pause before the second block starts. The condition (digit or letter) with which the trial starts is randomized for each test subject.
Time frame: assessed at baseline only
Differences in numerical skills between SCD or MCI participants and healthy controls as measured by Berlin Numeracy Test
The Berlin Numeracy Test contains 4 short, text-based questions testing statistical numeracy and risk literacy, requiring Bayesian inference for problems like understanding probabilities in health concerns (e.g., poisonous mushrooms) or lotteries, often presenting data in relative/absolute numbers and asking for probability estimates. Correct answers scored for a total of 0-4 points.
Time frame: assessed at baseline only
Plan to share: No
Started Oct 2025 (actual). Primary completion is estimated for Dec 2028, 38 months after the start.
Of 1,442 non-industry interventional studies with no phase under Cognitive Dysfunction, half reached primary completion within 27 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 51. This study's planned 38 months is above that.
Counting every sponsor, half of 1,511 studies reached it within 27 months; a quarter within 12 and three quarters within 50.
How these figures are worked out, and which studies are left out of them.
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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