Tyrosine Longevity Risk Calculator — Amino Acid × Lifespan Interactive Explorer

The Tyrosine–Lifespan Connection

A UK Biobank study of 272,475 people reveals that circulating tyrosine is causally linked to shorter lifespan — particularly in men. This is the first human evidence connecting a specific amino acid to longevity through Mendelian randomization.

Higher circulating tyrosine shortens male lifespan by −0.91 years (95% CI: −1.60 to −0.21), independent of phenylalanine. The effect is sex-specific: significant in men, attenuated in women. Phenylalanine shows no independent effect on lifespan after controlling for tyrosine.

272,475

Participants

23,964

Deaths Recorded

−0.91 yr

Male Lifespan Effect

74 SNPs

Genetic Instruments

Study Design

Dual approach: Cox regression in 272K UK Biobank participants + two-sample Mendelian randomization with 74 SNPs for tyrosine and 21 for phenylalanine, applied to parental attained age GWAS.

Key Innovation

First human MR study to disentangle tyrosine from phenylalanine effects on lifespan. Multivariable MR shows tyrosine's effect is independent — phenylalanine is not the driver.

Clinical Implication

Tyrosine supplements (marketed for "cognitive enhancement") may not support long-term health. Protein-restriction diets that lower tyrosine could be beneficial, especially for men.

Tyrosine & Phenylalanine Biology

Tyrosine (Tyr, Y) is a conditionally essential amino acid synthesized from phenylalanine. It sits at the hub of multiple metabolic pathways — neurotransmitters, thyroid hormones, melanin, and insulin signaling.

C₉H₁₁NO₃ · MW 181.19 · Code: Tyr / Y

L-Tyrosine

Conditionally essential. Synthesized from phenylalanine by PAH. Precursor to dopamine, norepinephrine, epinephrine, T3/T4 thyroid hormones, and melanin. Found in cheese, meat, fish, eggs, dairy, soy, nuts.

Longevity impactNEGATIVE ↓

C₉H₁₁NO₂ · MW 165.19 · Code: Phe / F

L-Phenylalanine

Essential amino acid (must come from diet). Converted to tyrosine by phenylalanine hydroxylase (PAH). Oxidizes to toxic meta-tyrosine. Associated with telomere loss and inflammation, but no independent lifespan effect.

Longevity impactNEUTRAL —

Key Amino Acids in Longevity

Amino Acid	Code	Essential?	Longevity Evidence	Mechanism	Strength
Tyrosine	Tyr / Y	Conditional	↓ Lifespan	IIS/mTOR activation, insulin resistance	High
Methionine	Met / M	Essential	↓ Lifespan	SAM cycle, mTOR, ROS production	Very High
BCAAs	Leu/Ile/Val	Essential	↓ Lifespan	mTORC1 activation, insulin resistance	High
Tryptophan	Trp / W	Essential	Mixed	Serotonin/kynurenine balance	Mod
Glycine	Gly / G	Non-essential	↑ Lifespan	Glutathione synthesis, methyl metabolism	Mod
Phenylalanine	Phe / F	Essential	No effect*	Only via tyrosine conversion; m-tyrosine toxicity	Low

*After controlling for tyrosine in multivariable MR. Observational data shows phenylalanine association, but MR reveals it is mediated through tyrosine.

UK Biobank Cohort Analysis

272,475 participants with plasma amino acid measurements (NMR, Nightingale Health), death records, and extensive phenotyping. Median follow-up: 11.1 years. Cox regression adjusted for age, BMI, Townsend deprivation, smoking, alcohol, physical activity, ethnicity, and education.

125,359

Men

147,116

Women

14,230

Male Deaths

9,734

Female Deaths

Cox Regression: Hazard Ratios per SD Increase

Disease-Specific Mortality (Overall)

Full Cox Regression Results

Exposure	Sex	HR	95% CI	p-value	Significance
Phenylalanine	Overall	1.04	1.03–1.05	1.1×10⁻⁹	★★★
Phenylalanine	♂ Men	1.04	1.02–1.05	7.1×10⁻⁷	★★★
Phenylalanine	♀ Women	1.04	1.02–1.07	1.2×10⁻³	★★
Tyrosine	Overall	1.02	1.00–1.03	2.1×10⁻²	★
Tyrosine	♂ Men	1.03	1.01–1.05	5.5×10⁻³	★★
Tyrosine	♀ Women	1.00	0.98–1.03	7.2×10⁻¹	NS

HR per 1 SD increase in amino acid. Adjusted for age, BMI, Townsend, smoking, alcohol, activity, ethnicity, education. NS = not significant.

Key Observational Finding

The divergence between phenylalanine and tyrosine is striking: phenylalanine raises mortality similarly in both sexes (HR ~1.04), but tyrosine shows a male-specific effect (HR 1.03 in men, 1.00 in women). The tyrosine-to-phenylalanine ratio is protective in women (HR 0.96) but null in men — suggesting efficient conversion of phenylalanine to tyrosine may be beneficial, while excess accumulation of free tyrosine is harmful. The Pearson correlation between the two amino acids is 0.52.

Sex-Specific Effects

The most striking finding: tyrosine's lifespan effect is sex-specific. In multivariable MR (controlling for phenylalanine), tyrosine shortens lifespan by −0.91 years in men but only −0.36 years in women (non-significant). Why?

Multivariable MR: Tyrosine Effect on Lifespan by Sex

MR Methods Comparison — Tyrosine in Men

Insulin Resistance × Sex Hormones

Tyrosine correlates with insulin resistance, which interacts with testosterone — more strongly associated with survival in men. Higher tyrosine → more IR → amplified by testosterone → shortened male lifespan.

Catecholamine Regulation

Dopamine and norepinephrine (from tyrosine) are regulated by sex hormones. Estrogen modulates dopamine turnover differently than testosterone, potentially buffering women against excess catecholamine effects.

Baseline Level Difference

Young women have lower circulating tyrosine than young men. Combined with nonlinear dose-response (turning point at standardized 0), women may operate below the harmful threshold more often.

Mendelian Randomization Analysis

MR uses genetic variants as instruments to infer causality — like a natural randomized experiment. Because SNPs are assigned at conception, they are less susceptible to confounding than observational data.

How MR Works in This Study

Identify genetic instruments

GWAS in UK Biobank identified 74 SNPs for tyrosine and 21 for phenylalanine reaching genome-wide significance (p < 5×10⁻⁸) and LD-pruned (r² < 0.001). Key genes: PAH, HPD, CPS1, SLC transporters.

Apply to lifespan outcome

SNP effects on amino acid levels were applied to parental attained age GWAS (389K participants). Parental lifespan serves as a proxy since longevity is heritable.

Multivariable MR

Since Phe and Tyr are correlated (r=0.52) and share some SNPs (rs140584594, rs10750864, rs1043011), multivariable MR was conducted to separate their independent effects.

Sensitivity analyses

Multiple robust methods (IVW, weighted median, weighted mode, MR-PRESSO, MR-Egger) plus leave-one-out and external GWAS replication without UK Biobank overlap.

MR: Life Years Change per Genetically Predicted AA Level

Genetic Instrument Strength (F-statistics)

Multivariable MR Results

Sex	Method	Exposure	Life Years	95% CI	p-value	MR-Egger Intercept p
♂ Men	IVW	Phenylalanine	+0.75	−0.07, +1.58	0.08	0.61
	IVW	Tyrosine	−0.80	−1.40, −0.23	0.006	0.61
	MR-Egger	Phenylalanine	+0.55	−0.59, +1.69	0.35
	MR-Egger	Tyrosine	−0.91	−1.60, −0.21	0.01
♀ Women	IVW	Phenylalanine	−0.72	−1.47, +0.05	0.07	0.15
	IVW	Tyrosine	−0.59	−1.11, −0.05	0.03	0.15
	MR-Egger	Phenylalanine	−0.18	−1.24, +0.85	0.73
	MR-Egger	Tyrosine	−0.36	−0.96, +0.23	0.24

Interpretation

The MR-Egger intercept p > 0.05 in both sexes confirms no directional pleiotropy. In men, both IVW (p=0.006) and MR-Egger (p=0.01) show tyrosine shortens lifespan, with consistent direction across all methods. In women, the IVW estimate reaches significance (p=0.03), but MR-Egger does not (p=0.24), suggesting the effect, if present, is weaker. Power calculations indicate the study can detect ~1.0 life-year effects for tyrosine at 80% power.

Dietary Sources & Supplement Risk

Tyrosine is abundant in high-protein foods. While the MR study assessed endogenous levels (not dietary intake directly), blood tyrosine responds to dietary protein and supplementation.

⚠️

L-Tyrosine Supplement Caution

L-Tyrosine is widely marketed for "cognitive enhancement," "mood support," and "stress resilience." Typical doses (500–2000 mg/day) significantly raise circulating tyrosine. This study's findings do not support long-term tyrosine supplementation for lifespan, particularly in men. Short-term, acute use (e.g., before stressful events) has different risk/benefit than chronic supplementation.

Tyrosine Content in Common Foods

🧀

Parmesan Cheese

1,995 mg / 100g · Named from cheese (tyrós)

🫘

Soy Protein Isolate

1,497 mg / 100g · Complete protein source

🥩

Beef (lean)

1,140 mg / 100g · High bioavailability

🐟

Salmon / Tuna

1,050 mg / 100g · Omega-3 may offset

🍗

Chicken Breast

1,020 mg / 100g · Lean protein

🥚

Egg Whites

~250 mg / egg · Moderate source

🥜

Peanuts / Almonds

~800 mg / 100g · Plant protein

🫛

Lima Beans / Lentils

~300 mg / 100g cooked · Lower source

Tyrosine Content by Food Category (mg/100g)

Practical Recommendations

1. Reconsider chronic tyrosine supplements — especially if male. Short-term cognitive benefits don't outweigh potential long-term lifespan costs.

2. Protein restriction diets lower tyrosine and are associated with lifespan extension across species. Consider time-restricted protein intake or plant-forward diets with lower tyrosine density.

3. Monitor the ratio — The tyrosine-to-phenylalanine ratio matters. Efficient PAH conversion (producing adequate tyrosine without excess) may be protective, especially in women.

4. Nonlinear dose-response — The harm appears above-average concentrations. The goal isn't zero tyrosine (impossible and harmful) but avoiding chronic excess.

5. Context matters — This study assessed lifelong genetic exposure, not short-term dietary changes. Supplementation for acute stress (military, extreme conditions) has a different risk profile.

Tyrosine Longevity Risk Estimator

Estimate your relative risk based on dietary and lifestyle factors that influence circulating tyrosine. This is an educational tool based on the study's findings — not a medical diagnostic.

Input Parameters

SexMale

♂ Male♀ Female

Age50

Daily Protein Intake (g)80

Tyrosine Supplement (mg/day)0

Protein Source (Plant ↔ Animal)50%

100% Plant100% Animal

Cheese / Dairy IntakeModerate

NoneLowModerateHigh

Physical Activity LevelModerate

SedentaryLightModerateVigorous

MODERATE RISK

Assessment

Adjust the sliders to see your personalized risk assessment.

Estimated Tyrosine Intake Breakdown

References

Primary study and supporting evidence.

Primary Study

Zhao JV, et al. The role of phenylalanine and tyrosine in longevity: a cohort and Mendelian randomization study. Aging (Albany NY). 2025;17(10). doi:10.18632/aging.206326. PMID: 41045493. PMC12606968.

Animal Models & Mechanistic Evidence

Kosakamoto H, et al. Sensing of the non-essential amino acid tyrosine governs the response to protein restriction in Drosophila. Nat Metab. 2022;4:944–959. doi:10.1038/s42255-022-00608-7.
Soultoukis GA, Partridge L. Dietary protein, metabolism, and aging. Annu Rev Biochem. 2016;85:5–34. doi:10.1146/annurev-biochem-060815-014422.
Grandison RC, Piper MDW, Partridge L. Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila. Nature. 2009;462:1061–1064. doi:10.1038/nature08619.
Kitada M, et al. The impact of dietary protein intake on longevity and metabolic health. EBioMedicine. 2019;43:632–640.

Mendelian Randomization Methodology

Timmers PR, et al. Genomics of 1 million parent lifespans implicates novel pathways and common diseases and distinguishes survival chances. eLife. 2019;8:e39856.
Bowden J, et al. Mendelian randomization with invalid instruments: effect estimation and bias detection through Egger regression. Int J Epidemiol. 2015;44:512–525.
Sanderson E, et al. An examination of multivariable Mendelian randomization in the single-sample and two-sample summary data settings. Int J Epidemiol. 2019;48:713–727.
Yang J, et al. Advantages and pitfalls in the application of mixed-model association methods. Nat Genet. 2014;46:100–106.

Tyrosine Biology & Neurotransmitters

Fernstrom JD, Fernstrom MH. Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain. J Nutr. 2007;137:1539S–1547S.
Jongkees BJ, et al. Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands—A review. J Psychiatr Res. 2015;70:50–57.
Layman DK, et al. Defining meal requirements for protein to optimize metabolic roles of amino acids. Am J Clin Nutr. 2015;101:1330S–1338S.

Sex Differences & Insulin Resistance

Austad SN, Fischer KE. Sex differences in lifespan. Cell Metab. 2016;23:1022–1033.
Bycroft C, et al. The UK Biobank resource with deep phenotyping and genomic data. Nature. 2018;562:203–209.
Fontana L, Partridge L, Longo VD. Extending healthy life span—from yeast to humans. Science. 2010;328:321–326.
Wang TJ, et al. Metabolite profiles and the risk of developing diabetes. Nat Med. 2011;17:448–453.

Amino Acids & Longevity

Green CL, et al. The effects of graded levels of calorie restriction: XIV. Global metabolomics screen reveals brown adipose tissue changes in amino acids, catecholamines, and antioxidants after short-term restriction in C57BL/6 mice. J Gerontol A. 2020;75:218–229.
Richardson NE, et al. Lifelong restriction of dietary branched-chain amino acids has sex-specific benefits for frailty and lifespan in mice. Nat Aging. 2021;1:73–86.
Miller RA, et al. Methionine-deficient diet extends mouse lifespan, slows immune and lens aging, alters glucose, T4, IGF-I and insulin levels, and increases hepatocyte MIF levels and stress resistance. Aging Cell. 2005;4:119–125.
Piper MDW, et al. Matching dietary amino acid balance to the in silico-translated exome optimizes growth and reproduction without cost to lifespan. Cell Metab. 2017;25:610–621.