If you follow health influencers or longevity experts online, you’ve likely heard about Nattokinase, an enzyme derived from fermented soybeans.

It’s frequently hyped as an inexpensive miracle supplement that can single-handedly melt away up to 95% of arterial plaque, offering a cheap alternative to expensive statins or invasive surgical procedures.

Influencers routinely point to scientific literature to back up these bold claims. But does the published research actually say what they claim it does?

To separate online hype from scientific reality, we ran a Tessa analysis on one of the primary systematic reviews frequently cited to validate nattokinase: “Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.“

Here is what Tessa revealed when we put this paper under the microscope.

What the Paper Actually Showed

Despite social media claims that nattokinase clears plaque and dramatically lowers cholesterol, this meta-analysis of randomized controlled trials (RCTs) found something very different:

• No Plaque Busting or Lipid Lowering: Across the pooled trial data, nattokinase showed no consistent lipid-lowering effect. In fact, lower total doses of nattokinase were actually associated with a slight increase in total cholesterol and LDL (“bad”) cholesterol, and a slight decrease in HDL (“good”) cholesterol.
• Modest Blood Pressure Reduction: The paper did confirm a small, statistically significant drop in blood pressure (roughly 3.4 mmHg systolic and 2.3 mmHg diastolic). While helpful, this modest drop is a far cry from replacing standard medical treatments.
• A Slight Increase in Blood Glucose: The analysis noted a small but statistically significant increase in fasting blood glucose among participants taking nattokinase.

The Tessa Overall Score

TScore: 66 / 100 ( Yellow – Caution)

A graphical illustration of Tessa’s analysis of the paper

Tessa Analysis Results

Tessa Sub-Scores

The Tessa Analysis Breakdown

While the authors followed standard PRISMA reporting protocols (achieving an 88% completeness score), Tessa Pro’s deep-dive evaluation highlighted major structural vulnerabilities in the underlying evidence:

• Methodological Quality (AMSTAR 2): Critically Low Confidence — Although the authors conducted duplicate screening and used standard risk-of-bias tools, the review suffered from critical methodological gaps. Key issues included an incomplete search strategy (excluding trial registries and grey literature), failure to provide a detailed list of excluded studies with justifications, and no reporting on the funding sources of the primary trials analyzed.
• Certainty of Evidence (GRADE): Very Low Certainty — When evaluated using the GRADE framework across 8 primary outcomes, the certainty of evidence dropped to Very Low for most findings, including LDL, HDL, blood pressure, and adverse event reporting. The primary driver for this rating was the small number of overall participants (only 6 RCTs totaling 546 subjects) combined with unexplained heterogeneity (variability) between trial results.
• Citation Integrity: Tessa’s citation engine verified 95% of the paper’s references with an average relevance score of 7.1/10, showing solid context alignment without evidence of aggressive citation padding.

The Bottom Line: While the systematic review itself was conducted in good faith, the actual primary data simply does not support the massive health claims circulating on social media.

See for yourself: Read the full, objective Tessa analysis report here (includes links to the study): https://www.tessapp.ai/report/39076715

If you’re interested in similar studies, check out the Tessa analysis of these:

• Cohort Study (1,062 people): (65 / 100 ( Yellow) — Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants. (Frontiers in cardiovascular medicine)
• Narrative Review: (50 / 100 ( Yellow) — Research Progress of Nattokinase in Reducing Blood Lipid. (Nutrients)

For decades, the conversation surrounding daily multivitamin-mineral (MVM) supplements has felt like a pendulum swing. Are they an essential insurance policy for your health, completely harmless but useless “expensive urine,” or somewhere in between?

A major study published in The American Journal of Clinical Nutrition offers some of the most rigorous data yet on how a daily multivitamin impacts the aging brain. The research, stemming from the massive Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) led by researchers at Harvard and Massachusetts General Hospital, specifically looked at cognitive decline in older adults.

To find out how much weight these findings truly hold, we ran the study through Tessa, our AI-powered research integrity and trustworthiness assessment system.

The Study at a Glance: What Did the Researchers Find?

The COSMOS researchers evaluated a specific subcohort of 573 participants over two years using detailed, in-person neuropsychological exams (the “COSMOS-Clinic” group). They also conducted a meta-analysis pooling data from over 5,000 participants across three separate COSMOS sub-studies (Clinic, Mind, and Web).

The headlines coming out of the study were highly encouraging:

• Memory Boost: In the in-person clinic group, daily multivitamin use led to a statistically significant, more favorable change in episodic memory over two years.
• Slowing Brain Aging: When looking at the pooled meta-analysis of all 5,000+ participants, daily multivitamins showed clear benefits for both global cognition and episodic memory.
• The “2-Year” Effect: Most notably, the researchers estimated that the magnitude of the multivitamin’s effect on global cognition was equivalent to reducing cognitive aging by roughly 2 years compared to the placebo group.

Inside the Data: Tessa’s Trustworthiness Breakdown

Tessa evaluates scientific papers across five distinct categories to generate an overall TScore (Trustworthiness Score) from 0 to 100.

COSMOS Cognitive Study Tessa Score: 80 (Green / High Trust)

A TScore of 80 is an excellent result in biomedical literature, indicating a highly rigorous study, though not entirely without caveats. Here is how Tessa broke down the paper’s strengths and limitations:

Where the Study Excelled

• High Experimental Rigor (90/100): This wasn’t just a survey asking people if they take vitamins. It was a randomized, double-blind, placebo-controlled clinical trial—the gold standard of medical evidence.
• Gold-Standard Testing: Unlike prior studies that relied purely on phone or internet surveys, the core clinic group underwent detailed, 45-minute, in-person neurological testing, which catches incredibly subtle shifts in brain function.
• Flawless Journal/Author Track Record: The authors hail from top-tier institutions (Harvard, Brigham and Women’s Hospital), and the publishing journal is highly respected, earning a perfect 100 on Tessa’s Journal scale.

Where Limitations Remained

• The “Missing Data” Factor: Tessa noted a minor risk of bias because about 14% of the in-person clinic participants did not complete their 2-year follow-up cognitive testing. While the researchers used statistical models to adjust for this, missing data always introduces a slight layer of uncertainty.
• Measurement Differences: The larger meta-analysis pooled data from people tested in three different ways: in-person, over the phone, and on a computer. Combining different testing methods can slightly obscure precision.
• Low Diversity: The clinic cohort was overwhelmingly non-Hispanic White (over 95%), meaning the results might not automatically generalize to the entire, diverse U.S. population.

The Verdict on the Multivitamin Debate

Does this settle the debate? Not entirely, but it moves the needle significantly. While this study doesn’t prove how multivitamins protect the brain, it provides some of the strongest evidence to date that a daily broad-based multivitamin is a safe, accessible tool to help slow cognitive decline as we age.

You can read our full, Tessa Summary Analysis Report, which features the above plus detailed researcher-institution relationship maps, a complete timeline of who has cited this paper, and an extracted figure gallery optimized for Google Image Search to verify scientific transparency.

Read the Full Tessa Summary Report here.

For Tessa subscribers, you can read the Deep Dive and full Citation Analysis here:
Deep Dive Analysis
Citation Analysis