Is a longevity DNA test worth it?

What it can and cannot tell you

Your DNA sequence stays the same for life. So a DNA test cannot measure how fast you are aging, or tell you how long you will live. What is biological age?

Studies disagree on how much of lifespan is inherited. Estimates range from under 10 percent to over half, depending on the method.

A test can find specific risks you can act on. Most useful results fall into three groups: medicines, rare variants with a clear next step, and conditions you could pass on to a child.

How you handle medicines

Some variants change how your body handles a medicine. In a UK study of 487,409 people, 99.5% carried at least one variant that may change their response to a drug. Nearly a quarter had already been prescribed such a drug.

Clopidogrel, a common blood thinner, is one example. People whose CYP2C19 gene works poorly have a higher risk of heart attack and stroke while taking it. Their body activates less of the drug.

CPIC, an expert group, publishes guidelines on how to use these results to choose and dose medicines. Take any result to your doctor or pharmacist before you change a medicine.

Rare variants with a clear next step

A few rare variants raise the risk of a serious condition a great deal. For some of them, acting early can prevent harm or reduce it.

The American College of Medical Genetics and Genomics (ACMG) lists 84 such genes. They include BRCA1 and BRCA2 for breast and ovarian cancer, and the Lynch syndrome genes for colon cancer. LDLR is on the list too, for familial hypercholesterolemia, an inherited form of high cholesterol.

These variants are uncommon. In a 2020 study of 26,906 people in Nevada, 1.33% carried one for breast and ovarian cancer, Lynch syndrome or familial hypercholesterolemia. That is about 1 in 75. Nine in ten of them had never been identified, and only a quarter said the disease ran in their family.

US screening guidelines still advise against routine BRCA testing for women with no personal or family history of these cancers and no ancestry linked to BRCA variants.

Conditions you could pass on to a child

Carrier screening looks for variants that usually cause no illness in you. If both parents carry a variant in the same gene, each child has a 1 in 4 chance of having the condition.

The ACMG recommends offering carrier screening to everyone who is pregnant or planning a pregnancy. The genes in the carrier screen.

What whole-genome sequencing adds

Most consumer DNA tests use an array, a chip that checks a chosen set of positions. A 2021 study compared arrays with sequencing in 49,908 people. For common variants, the arrays were right more than 99% of the time.

For very rare variants, they were mostly wrong. Only 16% of the rarest positive results were confirmed by sequencing. For BRCA1 and BRCA2, about 4 in 100 positive results were real.

Whole-genome sequencing measures your DNA directly, so rare variants are found in your own sample. Whole genome vs a DNA array.

Depth matters too. Depth is how many times each position is sequenced, on average. Leading clinical genome laboratories in the US and Canada set their minimum at 30x or 40x.

Some tests sequence each position less than once on average, under 1x, and estimate the rest from other people's genomes. That method was proposed as an alternative to arrays, for risk scores and common variants.

What risk scores can and cannot do

A polygenic risk score adds up many small genetic effects into one number. It compares your risk with other people's. It gives no timeline, and it is a probability, not a certainty.

A high score raises your chance above average. A low score lowers it without removing it.

Scores work best in people of European ancestry. In 2019, about 79% of the people in the genetic studies behind them were of European descent. In one large analysis, scores were 2.5 times less accurate in people of East Asian ancestry. In people of African ancestry, they were 4.9 times less accurate.

Before you act on a score, ask whether it was checked in people of your ancestry.

How to choose a test

• How much of your DNA it covers. An array, low-depth sequencing or a whole genome. For rare variants, ask for a whole genome at 30x or more.
• The laboratory. In the US, CLIA sets the federal quality standards for clinical laboratories. Ask whether the laboratory is CLIA-certified.
• Who reviews the results. Ask whether a qualified person checks each finding before it reaches you, and how a serious finding is confirmed. A rare finding should be confirmed with a clinical test before anyone acts on it.
• What you receive. A report that explains each result, its limits and a next step where there is one. Ask for your raw data files too, so you can take them elsewhere.
• What happens when the science changes. Variant classifications change over time. In one large laboratory, 91% of uncertain variants that were later reclassified turned out to be harmless. Ask whether you will hear about a change.
• Privacy. Ask whether the company shares your data with other companies, whether you can delete it, and what happens to it if the company is sold. In the US, a law called GINA protects you in health insurance and employment. It does not cover life, disability or long-term care insurance.

Who may not need one

• You have symptoms, or cancer runs in your family. Start with your doctor and a clinical test. Insurance may pay for it. In the US, BRCA genetic counseling is a covered preventive service for women at higher risk.
• A relative already has a known variant. Ask your doctor about a test for that one variant.
• You want ancestry and common traits only. An array is enough for that.
• You want a single number. DNA gives no lifespan and no biological age.
• You will not act on the results. A report you never use changes nothing.

What Helixir offers

Helixir offers one test: whole-genome sequencing from a cheek swab, at about 30x, in a CLIA-certified and CAP-accredited laboratory. A precision medicine analyst reviews every result in your report, including medicines, carrier status and the ACMG genes. A risk score appears only if it held up in people of your ancestry.

You get your report online and as a PDF, with your DNA file. The price is $1,750, everything included. How the analysis works.

Order your test or see an example report.

Sources

1. Ruby JG et al. Estimates of the heritability of human longevity are substantially inflated due to assortative mating. Genetics, 2018
2. Shenhar B et al. Heritability of intrinsic human life span is about 50% when confounding factors are addressed. Science, 2026
3. McInnes G et al. Pharmacogenetics at scale: an analysis of the UK Biobank. Clinical Pharmacology & Therapeutics, 2021
4. Lee CR et al. CPIC guideline for CYP2C19 genotype and clopidogrel therapy: 2022 update. Clinical Pharmacology & Therapeutics, 2022
5. Lee K et al. ACMG SF v3.3 list for reporting of secondary findings. Genetics in Medicine, 2025
6. Grzymski JJ et al. Population genetic screening efficiently identifies carriers of autosomal dominant diseases. Nature Medicine, 2020
7. US Preventive Services Task Force. BRCA-related cancer: risk assessment, genetic counseling and genetic testing, 2019
8. MedlinePlus. Autosomal recessive
9. Gregg AR et al. Screening for autosomal recessive and X-linked conditions during pregnancy and preconception: an ACMG practice resource. Genetics in Medicine, 2021
10. Weedon MN et al. Use of SNP chips to detect rare pathogenic variants. BMJ, 2021
11. Marshall CR et al. Best practices for the analytical validation of clinical whole-genome sequencing. npj Genomic Medicine, 2020
12. Li JH et al. Low-pass sequencing increases the power of GWAS and decreases measurement error of polygenic risk scores compared to genotyping arrays. Genome Research, 2021
13. National Human Genome Research Institute. Polygenic risk scores
14. Martin AR et al. Clinical use of current polygenic risk scores may exacerbate health disparities. Nature Genetics, 2019
15. CDC. Clinical Laboratory Improvement Amendments (CLIA)
16. MedlinePlus. What is direct-to-consumer genetic testing?
17. Mersch J et al. Prevalence of variant reclassification following hereditary cancer genetic testing. JAMA, 2018
18. Federal Trade Commission. If DNA test kits are on your holiday shopping list, 2023
19. National Human Genome Research Institute. Genetic discrimination
20. HealthCare.gov. Preventive care benefits for women

Informational and educational, not a diagnosis. Bring anything of medical consequence to your physician.