Private DNA testing is genetic testing you arrange yourself, outside the NHS, usually with a simple saliva sample sent to an accredited lab. A longevity DNA test looks at gene variants linked to how you age: cardiovascular and metabolic health, inflammation, brain health, nutrient needs, sleep and exercise response. The aim isn't to predict your lifespan. It's to show which lifestyle levers are likely to matter most for you, so you can act on them early.

If you see your health as a long-term investment, your DNA is the one dataset that never changes and never goes out of date.

Why is longevity so important to FitnessGenes?

For our founder and CEO, Dr Samantha (Sam) Decombel, longevity isn't a trend. Sam's dad died in his 50s, and his loss left her with a lasting drive to put her scientific knowledge to work and live as healthily as possible, for as long as possible.

In the 20 years since, she has made it her mission to learn everything she can about extending her healthy life, above all so she can be around for her kids for as long as possible. For Sam, longevity has become a conscious pursuit rather than something left to chance.

In practice, that pursuit looks like a lot of small, consistent choices. Sam exercises regularly, playing netball and running, and her lunch is usually a salad with oily fish such as salmon. None of it is extreme, and that's the point: the habits with the strongest evidence behind them for a longer, healthier life are the everyday ones you can keep up for decades.

That drive to understand what can be changed, and to act on it early, is the thinking behind FitnessGenes and, more recently, behind BASIL, our AI-driven longevity platform.

What does "private" DNA testing actually mean?

In the UK, NHS genetic testing is generally offered when there's a clinical reason: a suspected inherited condition, a strong family history, or a result that will change treatment. Private (or direct-to-consumer) DNA testing is something you choose to do yourself, without a referral, usually to understand your health, fitness or ageing in more depth.

"Private" also describes how your data should be handled. Under UK GDPR, genetic data is classed as special category data, which means providers must have a clear lawful basis for processing it and protect it to a higher standard. A good private provider will tell you exactly where your sample is analysed, how your data is stored, whether it's ever shared, and how to delete it.

At FitnessGenes, samples are processed in a laboratory holding ISO 17025 and ISO 9001 accreditation, and results are only released when at least 95% of the sample's genetic variants have been reliably identified. If you've already tested with a provider such as Ancestry or 23andMe, you can also upload your existing raw data rather than taking a new test.

Why do people choose private DNA testing for longevity?

Because healthy years, not just total years, are what most of us actually care about. The latest Office for National Statistics figures show that between 2022 and 2024, men in the UK could expect to spend 60.7 years in good health and women 61.3 years. That's the lowest level since records began in 2011 to 2013, and it means roughly a quarter of a woman's life, and just under a quarter of a man's, is likely to be spent in poorer health.

Most of the conditions that eat into those years, such as heart disease, type 2 diabetes and cognitive decline, develop slowly over decades. A longevity test gives you a head start: it highlights where your genetic predispositions lie, well before a blood marker or a symptom tells you something is wrong.

How much of longevity is actually genetic?

It depends on how you measure it, and the answer has shifted recently.

A 2018 analysis of family trees covering more than 400 million people put the heritability of lifespan below 10%, once partners' shared lifestyles were accounted for. But a 2026 study in Science from the Weizmann Institute argued that this underestimates genetics. By separating deaths caused by ageing from those caused by accidents and infections, it put the genetic contribution to "intrinsic" lifespan at around 50%.

Either way, a large share of how long you live comes down to how you live. A Harvard analysis of more than 120,000 adults found that people who followed five low-risk habits (not smoking, a healthy BMI, regular physical activity, moderate alcohol intake and a good-quality diet) had a life expectancy at 50 that was 14 years longer for women and 12.2 years longer for men than those who followed none. Regular activity and a good-quality diet are exactly what Sam has built her routine around.

Your genes load the dice; your habits roll them. Understanding your genetics can help you decide where to focus your effort.

What does a longevity DNA test include?

A longevity-focused DNA test analyses variants in genes involved in the biological processes that shape how we age. At FitnessGenes, these sit across our health categories, and typically include:

  • Heart health: variants linked to cholesterol levels, blood pressure and cardiovascular risk, including genes such as APOE, which influences how your body processes dietary fat.
  • Blood sugar and metabolism: how efficiently you manage glucose and respond to carbohydrates, which matters for long-term metabolic health.
  • Inflammation: genes that influence your baseline inflammatory response. Chronic, low-grade inflammation ("inflammageing") is considered one of the hallmarks of ageing.
  • Brain health: variants associated with cognitive ageing, and with how diet, sleep and exercise may support brain function over time.
  • Vitamin and mineral requirements: whether you may need more of certain nutrients, such as vitamin D, folate or omega-3, or need to watch others, such as iron (HFE).
  • Sleep health: your chronotype and genetic tendencies around sleep quality and duration, a major but often overlooked longevity lever.
  • Exercise response: whether you're likely to respond better to endurance or strength training, and how you recover. Muscle mass and cardiorespiratory fitness are two of the strongest predictors of healthy ageing.
  • Biological ageing: variants in pathways linked to cellular ageing and longevity, such as FOXO3, a gene repeatedly associated with exceptional longevity in human populations.

Each result comes with actionable recommendations covering nutrition, exercise, sleep, supplements and lifestyle.

What is BASIL and how does it use your DNA?

BASIL (Biological Assessment System for Improved Longevity) is FitnessGenes' AI-driven longevity platform, developed by our Chief Scientific Officer and co-founder, Dr Stuart Grice.

Most people interested in longevity don't have a data problem. They have a prioritisation problem. Between DNA results, blood panels, wearables and a constant stream of new advice, it's hard to know what to actually do first. BASIL is designed to solve that.

It combines your DNA with your other health data, using our TrueTrait™ model, which integrates genetic and lifestyle information. It then objectively ranks and organises that data to highlight the daily actions likely to have the greatest impact on your long-term health. Rather than a long list of results, you get a clear order of priorities.

It's the tool Sam wanted for herself: science-led, personalised, and focused on what she can change to stay healthy for longer.

Can a healthy lifestyle outweigh a high genetic risk?

Often, yes, and this is one of the most encouraging findings in longevity research.

A study of more than 55,000 people published in the New England Journal of Medicine found that, among those at high genetic risk of coronary heart disease, following a favourable lifestyle was associated with a 46% lower relative risk of coronary events compared with an unfavourable lifestyle.

How do you choose a private DNA testing provider?

Before you buy a longevity test, check:

  • Lab accreditation: look for standards such as ISO 17025 and quality control thresholds for results.
  • Data privacy: where your data is stored, whether it's shared or sold, and how to delete it.
  • Scientific credibility: whether the team includes qualified geneticists and scientists, and whether reports cite peer-reviewed research.
  • Actionability: whether results come with practical recommendations, not just a list of gene variants.
  • Control over sensitive results: whether you can choose not to receive results linked to disease risk.
  • Integration: whether the platform can combine your DNA with blood tests and lifestyle data to show you what to prioritise.

FAQs

Is private DNA testing legal in the UK?

Yes. Direct-to-consumer genetic testing is legal in the UK. Providers must comply with UK data protection law, under which genetic data is classed as special category data that requires extra protection.

What's the difference between a longevity DNA test and an ancestry test?

Ancestry tests focus on where your ancestors came from. A longevity test interprets variants linked to health, metabolism and ageing, and turns them into lifestyle recommendations. If you've already done an ancestry test, you can often upload the raw data to FitnessGenes for health and longevity insights.

Will a longevity test tell me how long I'll live?

No. No DNA test can predict your lifespan. Genetics accounts for a relatively small share of how long we live; the value of a longevity test lies in showing which lifestyle changes are likely to matter most for you.

Can a DNA test tell me I'm at risk of a serious disease?

Most longevity and wellness tests focus on predispositions rather than diagnosing disease. At FitnessGenes, our specialism is health and fitness interpretation; where results relate to disease-associated genes, you are given the choice of whether to receive them.

Do I need to repeat a DNA test?

No. Your DNA doesn't change, so it's a one-off test. What changes is the research: as new studies are published, your results can be reinterpreted and updated.

How is a longevity DNA test different from a blood test?

A blood test shows what's happening in your body right now; a DNA test shows your underlying predispositions. Together they give context: your genetics can explain why a marker such as cholesterol or ferritin might be raised, and blood tests show whether your changes are working.

What does BASIL add to my DNA results?

BASIL combines your DNA with your other health data and ranks it, so instead of a long list of reports you see the daily actions most likely to improve your long-term health, in order of priority.

 

References

Office for National Statistics (2026) Healthy life expectancy, UK: between 2011 to 2013 and 2022 to 2024. Available at: https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/healthandlifeexpectancies/bulletins/healthstatelifeexpectanciesuk/between2011to2013and2022to2024

Horvath, S. (2013) 'DNA methylation age of human tissues and cell types', Genome Biology, 14(10), R115. Available at: https://doi.org/10.1186/gb-2013-14-10-r115

Khera, A.V., Emdin, C.A., Drake, I., et al. (2016) 'Genetic risk, adherence to a healthy lifestyle, and coronary disease', New England Journal of Medicine, 375(24), pp. 2349-2358. Available at: https://doi.org/10.1056/NEJMoa1605086

Li, Y., Pan, A., Wang, D.D., et al. (2018) 'Impact of healthy lifestyle factors on life expectancies in the US population', Circulation, 138(4), pp. 345-355. Available at: https://doi.org/10.1161/CIRCULATIONAHA.117.032047

Passarino, G., De Rango, F. and Montesanto, A. (2016) 'Human longevity: genetics or lifestyle? It takes two to tango', Immunity & Ageing, 13, 12. Available at: https://doi.org/10.1186/s12979-016-0066-z

Ruby, J.G., Wright, K.M., Rand, K.A., et al. (2018) 'Estimates of the heritability of human longevity are substantially inflated due to assortative mating', Genetics, 210(3), pp. 1109-1124. Available at: https://doi.org/10.1534/genetics.118.301613

Willcox, B.J., Donlon, T.A., He, Q., et al. (2008) 'FOXO3A genotype is strongly associated with human longevity', Proceedings of the National Academy of Sciences, 105(37), pp. 13987-13992. Available at: https://doi.org/10.1073/pnas.0801030105

Shenhar, B., Pridham, G., De Oliveira, T. L., et al. (2026). Heritability of intrinsic human life span is about 50% when confounding factors are addressed. Science, 391, 504–510. https://doi.org/10.1126/science.adz1187