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Spd4.2
Spermidine Research
Probably helps
34 peer-reviewed studies
What the evidence says
Probably helps
Spermidine helped in about half (2/4) of the studies that measured an effect — promising, but not unanimous.
Most evidence is from high-quality randomised trials published 2009–2026 with a typical study size of 38 participants.
Based on 34 studies · 12 RCTs · 2,747 total participants
Confidence
High confidence
What the studies found
2helped1unclear1didn't help· 30 more without graded effect data
By outcome
Longevity & agingLower mortality in observational cohorts only; no longevity trial in humans · Ongoing
Probably helps32 studies
Cognitive function
Mostly mechanism / observational7 studies
Neuroprotection & brain agingLargest RCT found no memory benefit; small pilots mixed · Ongoing
Mostly mechanism / observational5 studies
InflammationInflammatory-marker changes seen only in small pilots · Ongoing
Mostly mechanism / observational5 studies
Heart & blood pressure
Mostly mechanism / observational4 studies
Therapeutic & clinical
Mostly mechanism / observational3 studies
Immune support
Too few graded studies2 studies
Fertility & reproductive
Too few graded studies1 study
Safety profile
Too few graded studies1 study
By the numbers
Pulled from 26 studies with measurable effects
Likely real effects
50%
across studies
People studied
2,747
typical study: 38 people
Strongest designs
12
0 pooled, 12 randomised
Showed benefit
50%
2/4 studies
How long studies ran
1–3 months
3
3+ months
1
Populations Studied
General population2
Adults2
Older adults with subjective cognitive decline2
Patients with abdominal aortic aneurysm1
Active research area
24 studies in the last 5 years
200920172026
1Gut dysbiosis in abdominal aortic aneurysmSystematic ReviewCited 3×2024
With our expanding knowledge of the downstream pathogenic mechanisms of gut dysbiosis, novel therapeutics such as short-chain fatty acids and spermidine, as well as prognostic biomarkers such as TM...
Chui ESH et al. · Asian journal of surgery (2024)
With our expanding knowledge of the downstream pathogenic mechanisms of gut dysbiosis, novel therapeutics such as short-chain fatty acids and spermidine, as well as prognostic biomarkers such as TMAO have yielded promising preclinical results.
In conclusion, there is strong evidence corroborating the role of gut dysbiosis in the pathogenesis of AAA, wherein its therapeutic and prognostic potential deserves further exploration.
2Intestinal aging and polyamine availabilityReview2026
In conclusion, modulating the diet-microbiota-polyamine axis represents a promising strategy to promote healthy intestinal aging, meriting deeper mechanistic exploration and validation through clinical studies.
Mafe AN et al. · Nutrients (2026)
It further discusses how age-associated dysbiosis disrupts these interactions and evaluates nutritional and microbial-based strategies such as fermented foods, prebiotics, and probiotics that may enhance polyamine availability and restore gut homeostasis.
From the standpoint of food microbiology and human physiology, this synthesis underscores the translational potential of targeting microbial polyamine production through diet-based interventions.
This article presents a narrative review synthesizing experimental, animal, and emerging human evidence on microbial and dietary polyamines in intestinal aging.
Bringing together current knowledge on the significance of spermidine in both plants and humans, this review aims to trace its journey From Farm to Pharm, highlighting its importance for sustainable crop production, improved nutrition, and emerging pharmacological applications.
Blagojević BD, Brunel-Muguet S, Šućur R, Mladenov V, Balaž I, Vollmann J, Fotopoulos V, Mäder K. · NPJ science of food (2026)
From the aspect of human health, spermidine is mainly studied for healthy ageing properties and has been associated with cardioprotective, neuroprotective, and anti-cancerogenic effects.
On the other hand, being present in all plants, spermidine is essential for growth, development, and stress adaptation.
Endogenously or when exogenously applied, spermidine can help plants adapt to harsh climate change conditions.
5Colorectal adenomatous polyp riskObservationalCited 41×n=1,164 · large study2012
This study showed a role for dietary polyamines in colorectal adenoma risk.
Vargas AJ et al. · The American journal of clinical nutrition (2012)
Large harm
← WorseNo effectBetter →
A dietary intake of polyamines above the median amount in the study population was associated with 39% increased risk of colorectal adenoma at follow-up (adjusted OR: 1.39; 95% CI: 1.06, 1.83) in the pooled sample.
In addition, younger participants (OR: 1.94; 95% CI: 1.23, 3.08), women (OR: 2.43; 95% CI: 1.48, 4.00), and ODC GG genotype carriers (OR: 1.59; 95% CI: 1.00, 2.53) had significantly increased odds of colorectal adenoma if they consumed above-median polyamine amounts.
This study showed a role for dietary polyamines in colorectal adenoma risk.
6Safety and tolerability of spermidine supplementationRCTCited 9×n=37 · small study2024
These findings suggest that hpSPD at 40 mg/day for up to 28 days is safe and well-tolerated in healthy older men.
Keohane P et al. · Nutrition research (New York, N.Y.) (2024)
These findings suggest that hpSPD at 40 mg/day for up to 28 days is safe and well-tolerated in healthy older men.
The study is consistent with preclinical results and provides important evidence supporting the safety of high-purity spermidine supplementation, enabling further research with single-molecule spermidine to investigate its potential biology for improving human health.
This trial was registered at clinicaltrials.gov (NCT05459961).
8Mnemonic discrimination performanceRCTCited 69×n=100 · medium study2022
In this randomized clinical trial, longer-term spermidine supplementation in participants with subjective cognitive decline did not modify memory and biomarkers compared with placebo.
Schwarz C et al. · JAMA network open (2022)
No clear effect
← WorseNo effectBetter →
Could be chance
A total of 100 participants (51 in the spermidine group and 49 in the placebo group) were included in the analysis (mean [SD] age, 69 [5] years; 49 female participants [49%]).
Over 12 months, no significant changes were observed in mnemonic discrimination performance (between-group difference, -0.03; 95% CI, -0.11 to 0.05; P = .47) and secondary outcomes.
In this randomized clinical trial, longer-term spermidine supplementation in participants with subjective cognitive decline did not modify memory and biomarkers compared with placebo.
Intake of the combined supplements showed they were bioavailable and increased in plasma in a dose-dependent manner and provide preliminary data showing enhanced plasma anti-inflammatory and antiox...
Rhodes CH et al. · Nutrition research (New York, N.Y.) (2024)
Intake of the combined supplements showed they were bioavailable and increased in plasma in a dose-dependent manner and provide preliminary data showing enhanced plasma anti-inflammatory and antioxidant functions.
This trial was registered at clinicaltrials.gov (NCT05017428).
10Spermidine levels in blood plasma and salivaCrossoverCited 26×n=12 · very small study2023
It is rather unlikely that spermidine supplements with doses <15 mg/d exert any short-term effects.
Senekowitsch S et al. · Nutrients (2023)
The plasma metabolome was investigated using nuclear magnetic resonance (NMR) metabolomics. (3) Results: Compared with a placebo, spermidine supplementation significantly increased spermine levels in the plasma, but it did not affect spermidine or putrescine levels.
No effect on salivary polyamine concentrations was observed. (4) Conclusions: This study's results suggest that dietary spermidine is presystemically converted into spermine, which then enters systemic circulation.
Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine.
The results of this study reveal multiple functionalities and immunological pathways affected by PF in humans, identify candidates for the development of fasting mimetic compounds, and uncover targets for investigation in longevity research.
Rhodes CH et al. · The American journal of clinical nutrition (2023)
Furthermore, we found that these metabolites and their combination significantly extended the median lifespan of C. elegans by as much as 96%.
The results of this study reveal multiple functionalities and immunological pathways affected by PF in humans, identify candidates for the development of fasting mimetic compounds, and uncover targets for investigation in longevity research.
12Reactive hyperemia index (RHI)RCTCited 48×n=44 · small study2019
This study suggests that consuming Bifal + Arg YG prevents or reduces the risk of atherosclerosis.
Matsumoto M et al. · Nutrients (2019)
The reactive hyperemia index (RHI), the primary outcome, was measured using endo-peripheral arterial tone (EndoPAT).
The change in RHI from week 0 to 12 in the Bifal + Arg YG group was significantly higher than that in the placebo group, indicating that Bifal + Arg YG intake improved endothelial function.
This study suggests that consuming Bifal + Arg YG prevents or reduces the risk of atherosclerosis.
13Biomarkers of autophagy and cardiometabolic healthPilotCited 1×n=12 · very small study2025
This pilot study found that 3.3 mg/day of spermidine from Miricell® rice germ extract tends to improve biomarkers of autophagy, neuroprotection, and cardiometabolic health.
Bruno G et al. · Alternative therapies in health and medicine (2025)
Noticeable benefit
← WorseNo effectBetter →
Compared to baseline, only the 3.3 mg dose of spermidine from Miricell® increased Beclin-1 by 7.3%, ULK-1 by 13.4%, and BDNF by 12.1%.
Compared to baseline, the same dose resulted in a 20.8% decrease in hs-CRP, a 20.1% decrease in VLDL, and a 26.9% decrease in triglycerides.
This pilot study found that 3.3 mg/day of spermidine from Miricell® rice germ extract tends to improve biomarkers of autophagy, neuroprotection, and cardiometabolic health.
14Cognitive performance improvementRCTCited 47×n=85 · small study2021
By comparison, the group which had a lower spermidine intake showed consistent or declining cognitive performance.
Pekar T et al. · Wiener klinische Wochenschrift (2021)
Noticeable benefit
← WorseNo effectBetter →
Likely real
Blood samples were taken for the determination of spermidine concentration and measurement of metabolic parameters.
The results demonstrated a clear correlation between the intake of spermidine and the improvement in cognitive performance in subjects with mild and moderate dementia in the group treated with the higher spermidine dosage.
The most substantial improvement in test performance was found in the group of subjects with mild dementia with an increase of 2.23 points (p = 0.026) in the mini mental state examination (MMSE) and 1.99 (p = 0.47) in phonematic fluidity.
In this pilot trial, nutritional spermidine was associated with a positive impact on memory performance in older adults with subject cognitive decline.
Wirth M et al. · Cortex (2018)
Phase IIa pilot trial in 30 cognitively intact older adults (60-80 years) with subjective cognitive decline given a spermidine-rich plant extract for 3 months.
Memory performance was moderately enhanced in the spermidine group versus placebo (Cohen's d = .77; 95% CI crossed zero).
Mnemonic discrimination ability improved in the spermidine group with a medium effect size; no similar effect in placebo.
16Disease progression predictionRCTCited 61×n=38 · small study2018
This proof-of-concept study demonstrates that the metabolomics has a role in evaluating the biological effect of an investigational drug and may be a candidate biomarker as a secondary outcome measure in clinical trials.
Blasco H et al. · PloS one (2018)
To predict SVC from SM C24:1 in group O and SVC from SM OH C22:2 and SM C16:1 in group P+O, we noted a median sensitivity between 67% and 100%, a specificity between 66.7 and 71.4%, a positive predictive value between 66 and 75% and a negative predictive value between 70% and 100% in the test sets.
Changes in metabolomic profiles were closely linked to clinical progression, and correlated with glutamine levels in Group P and amino acids, lipids and spermidine levels in Group O.
Multivariate models accurately predicted disease progression and highlighted the discriminant role of sphingomyelins (SM C22:3, SM C24:1, SM OH C22:2, SM C16:1).
Similarly, no significant effect on the production of proinflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and anti-inflammatory interleukin-10 (IL-10) was induced by...
Manzoni MSJ et al. · Food research international (Ottawa, Ont.) (2017)
Similarly, no significant effect on the production of proinflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and anti-inflammatory interleukin-10 (IL-10) was induced by the synbiotic or placebo beverages consumption.
The results herein indicate that both the synbiotic and the placebo beverage consumption have increased polyamines levels, which are often reduced in elderly individuals, without influencing inflammatory responses.
In addition, both placebo and synbiotic beverages seems to contribute by maintaining increased polyamines levels.
Chen Y et al. · International journal of rheumatic diseases (2026)
Rheumatoid arthritis (RA) is a chronic autoimmune disease that not only severely impairs joint function but also leads to various systemic complications, significantly reducing patients' quality of life.
This review provided a comprehensive overview of the potential mechanisms of SPD in the pathological progression of RA, including the inhibition of inflammatory cytokines expression, reduction of oxidative stress, modulation of immune cell functions, and maintenance of bone metabolism homeostasis.
Through these mechanisms, SPD shows potential as a promising novel candidate for RA therapy.
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Lugart C et al. · Molecular human reproduction (2026)
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We summarize current evidence on their individual and combined roles in preserving muscle function and discuss their potential relevance for promoting healthy muscle aging and counteracting sarcopenia.
Attili L, Rossi MN, Di Santo R, Duranti G, Ceci R, Cervelli M. · Mechanisms of ageing and development (2026)
SMOX expression is maintained in healthy muscle but declines in atrophic conditions.
By converting spermine into spermidine, SMOX may help sustain autophagy-related pathways and support muscle mass under physiological conditions.
This review explores the interplay between exercise, spermidine, and SMOX, highlighting autophagy as a unifying regulatory axis.