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Popular Supplement Ingredient Linked to Shorter Lifespan in Men (opens in a new tab)

scitechdaily.com · 2026-05-13

Short answerEvidenceSource

Short answer

Mostly supported

Mostly supported.

The claims we could check match the study, but some claims were not covered by the evidence reviewed.

  • 3 supported
  • 1 not covered

Checked against the study summary. The full text wasn't available, so some details couldn't be settled either way.

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1
2

NewsLink checks it

Mostly supported

Every claim we could check holds up. Three of four claims match the study. This overall rating is based only on the claims we could check. One claim the study doesn't address.

  • 3 supported
  • 1 not covered
Open claim evidence
3
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Evidence layer

Claim by claim

Each claim gets a verdict. Expand it to see the evidence directly below.

4 claims in this story

Showing all 4 claimsChoose a verdict to focus the list.

Claim 1 of 4Not coveredResearchers from the University of Hong Kong and the University of Georgia analyzed health and genetic data from more than 270,000 people in the UK Biobank, and their study was published in Aging.View evidenceHide evidence

As statedmore than 270,000 people

Why this verdict

The profile supports that the paper used UK Biobank cohort and genetic/MR data, but at abstract depth it does not verify the author affiliations, journal name, or the stated sample size of more than 270,000 people. Those bibliographic and numerical details may be true, but they are not established by the supplied abstract-level profile.

1

Study evidence

Higher circulating tyrosine was associated with shorter lifespan in the UK Biobank observational analysis (Cox regression); sex-specific differences were examined and described as potential.

“We applied cohort study design and Mendelian randomization (MR) analysis.”
2

Study evidence

Tyrosine was associated with shorter lifespan in MR analyses (also observed in the cohort analysis).

“To test causality, in two-sample MR analysis, we used genetic variants associated with phenylalanine and tyrosine in UK Biobank with genome-wide significance and uncorrelated (r2 < 0.001) with each other, and applied them to large genome-wide association studies of lifespan, including parental, paternal, and maternal attained ages in the UK Biobank.”
Claim 2 of 4SupportedA large new study suggests that higher levels of the amino acid tyrosine in the bloodstream may be linked to a shorter lifespan in men.View evidenceHide evidence

As statedshorter lifespan in men

Why this verdict

The abstract-level profile supports a hedged, associational framing that higher circulating/genetically predicted tyrosine was associated with shorter lifespan, with a potential sex disparity and a clearer mutually adjusted MR result in men. The headline does not assert proof or supplementation effects, so it does not outrun the evidence as framed.

1

Study evidence

Higher circulating tyrosine was associated with shorter lifespan in the UK Biobank observational analysis (Cox regression); sex-specific differences were examined and described as potential.

“We applied cohort study design and Mendelian randomization (MR) analysis.”
2

Study evidence

Tyrosine was associated with shorter lifespan in MR analyses (also observed in the cohort analysis).

“To test causality, in two-sample MR analysis, we used genetic variants associated with phenylalanine and tyrosine in UK Biobank with genome-wide significance and uncorrelated (r2 < 0.001) with each other, and applied them to large genome-wide association studies of lifespan, including parental, paternal, and maternal attained ages in the UK Biobank.”
Claim 3 of 4SupportedIn men, after adjusting for phenylalanine, higher tyrosine levels were associated with a lifespan reduction of about 0.9 years, while women did not show a statistically clear association.View evidenceHide evidence

As statedabout 0.9 years

Why this verdict

This matches the multivariable MR result reported in the abstract-level profile: after controlling for phenylalanine, genetically higher tyrosine was associated with shorter lifespan in men by −0.91 years, while the estimate in women was −0.36 years with a 95% CI crossing the null, so not statistically clear.

1

Study evidence

In multivariable MR mutually adjusting for phenylalanine, genetically higher tyrosine was associated with shorter lifespan in men.−0.91 years (95% CI −1.60 to −0.21)

“We also conducted multivariable MR to examine the independent role of phenylalanine and tyrosine.”
Claim 4 of 4SupportedThe researchers caution that the study does not prove tyrosine supplements shorten lifespan and did not directly test supplementation.View evidenceHide evidence

Why this verdict

The supplied profile describes observational cohort and genetic epidemiology/MR analyses, not a supplementation trial, so the story’s caveat that the study did not directly test tyrosine supplementation is supported. The profile also notes that observational associations cannot by themselves establish causality; however, the exact wording that 'researchers caution' this is not independently verifiable from the abstract-level profile.

1

Study evidence

Higher circulating tyrosine was associated with shorter lifespan in the UK Biobank observational analysis (Cox regression); sex-specific differences were examined and described as potential.

“We applied cohort study design and Mendelian randomization (MR) analysis.”
2

Study evidence

Tyrosine was associated with shorter lifespan in MR analyses (also observed in the cohort analysis).

“To test causality, in two-sample MR analysis, we used genetic variants associated with phenylalanine and tyrosine in UK Biobank with genome-wide significance and uncorrelated (r2 < 0.001) with each other, and applied them to large genome-wide association studies of lifespan, including parental, paternal, and maternal attained ages in the UK Biobank.”
Then look for missing context

Context layer

What the story left out

Important study details the story did not include.

  • Phenylalanine showed no association with lifespan in either men or women after controlling for tyrosine in multivariable MR.

    The story mentions phenylalanine mainly as an amino acid considered alongside tyrosine and as an adjustment variable, but it does not clearly state the paper’s null finding for phenylalanine after controlling for tyrosine. This omission could matter because the paper distinguishes tyrosine from its precursor phenylalanine.

    From two-sample Mendelian randomization; multivariable Mendelian randomization

5 things the story did carry across
  • The paper combines a UK Biobank prospective cohort analysis of circulating phenylalanine and tyrosine with all-cause mortality/longevity outcomes, including sex-stratified Cox models.
  • The paper also uses two-sample Mendelian randomization to test whether genetically predicted phenylalanine and tyrosine have causal effects on lifespan-related outcomes.
  • In multivariable MR, higher genetically predicted tyrosine after adjustment for phenylalanine was associated with shorter lifespan in men, approximately −0.91 years, but not clearly in women.
  • Observational cohort associations cannot by themselves establish causality, and the paper addresses causality separately through MR.
  • The study did not directly test dietary protein restriction, food avoidance, or tyrosine supplementation as interventions.
Then read the study layer

Study layer

Study at a glance

Scan the study first. Expand only the parts you want to inspect.

Pieces of work

3

Evidence read

study summary

Lead result

secondary data

1Lead resultsecondary dataEstimate the association between circulating phenylalanine and tyrosine and all-cause mortality/longevity in UK Biobank, including sex-specific effects.Prospective cohort (UK Biobank) with Cox proportional hazards regression; sex-stratified analysisExpand

In plain English

In a prospective cohort analysis of UK Biobank participants, baseline circulating concentrations of the amino acids tyrosine and phenylalanine were examined for association with all-cause mortality using Cox proportional hazards regression, including sex-stratified models. The abstract reports that higher tyrosine was associated with shorter lifespan in the observational analysis, with potential sex-specific differences; phenylalanine is not emphasized as associated in the observational summary. The paper pairs this cohort analysis with Mendelian randomization as a causal triangulation, but the cohort result is presented as the primary in-sample association.

Key findings

  • Higher circulating tyrosine was associated with shorter lifespan in the UK Biobank observational analysis (Cox regression); sex-specific differences were examined and described as potential.
“We applied cohort study design and Mendelian randomization (MR) analysis.”
What this piece can’t prove
  • Observational cohort associations cannot by themselves establish causality (the paper uses MR for causal inference).

2 further details could not be confirmed from the summary.

2secondary dataTest whether phenylalanine and tyrosine have causal effects on lifespan outcomes using two-sample Mendelian randomization (including sex-stratified analyses).two-sample Mendelian randomizationExpand

In plain English

Two-sample Mendelian randomization (MR) using genome-wide significant, independent genetic variants for phenylalanine and tyrosine identified in the UK Biobank, applied to large lifespan GWAS (including parental, paternal, and maternal attained ages) to test causal effects overall and in sex-stratified analyses; multivariable MR was used to estimate independent effects of phenylalanine and tyrosine.

Key findings

  • Tyrosine was associated with shorter lifespan in MR analyses (also observed in the cohort analysis).
  • In multivariable MR adjusting for phenylalanine, higher tyrosine was associated with shorter lifespan in men.−0.91 years of life (95% CI −1.60 to −0.21)
“To test causality, in two-sample MR analysis, we used genetic variants associated with phenylalanine and tyrosine in UK Biobank with genome-wide significance and uncorrelated (r2 < 0.001) with each other, and applied them to large genome-wide association studies of lifespan, including parental, paternal, and maternal attained ages in the UK Biobank.”
What this piece can’t prove
  • Abstract does not report details on the number of genetic instruments, instrument strength (e.g., F-statistics), or tests for horizontal pleiotropy or heterogeneity.

2 further details could not be confirmed from the summary.

3secondary dataAssess the independent (mutually adjusted) roles of phenylalanine and tyrosine on lifespan using multivariable Mendelian randomization.multivariable Mendelian randomizationExpand

In plain English

Multivariable Mendelian randomization (MVMR) was used to estimate the independent (mutually adjusted) effects of circulating tyrosine and phenylalanine on lifespan. In MVMR, genetically predicted higher tyrosine was associated with shorter lifespan in men after adjustment for phenylalanine (−0.91 years, 95% CI −1.60 to −0.21) but not in women (−0.36 years, 95% CI −0.96 to 0.23). Phenylalanine showed no association with lifespan in either sex after controlling for tyrosine.

Key findings

  • In multivariable MR mutually adjusting for phenylalanine, genetically higher tyrosine was associated with shorter lifespan in men.−0.91 years (95% CI −1.60 to −0.21)
  • In multivariable MR mutually adjusting for phenylalanine, genetically higher tyrosine was not clearly associated with shorter lifespan in women.−0.36 years (95% CI −0.96 to 0.23)
“We also conducted multivariable MR to examine the independent role of phenylalanine and tyrosine.”
What this piece can’t prove
  • Abstract does not report MVMR diagnostic metrics (e.g., conditional instrument strength, F-statistics) or sensitivity analyses addressing pleiotropy.

2 further details could not be confirmed from the summary.

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Papers considered

The selected paper, plus nearby candidates.

PubMed, Europe PMC, Crossref · 34 candidate papers

And 28 more candidates considered.