Imagine receiving a test result that tells you your body is biologically five years older than your chronological age. You exercise regularly, get good sleep, eat healthy meals and have a happy personal life. What have you been doing wrong? Can this test be trusted?

Dozens of companies are marketing products that promise to reveal a person’s “true” biological age – that is, how well your body is functioning – for a price ranging from around US$30 to over $1,000. These products are based on epigenetic aging clocks, which are research tools that estimate age based on a person’s DNA. These clocks are reshaping how scientists study aging and how the public thinks about it.

But while epigenetic clocks are highly effective research tools to study aging at the population level, they aren’t designed to make claims about the health of individuals.

We are biobehavioral health scientists who study how early development and environmental factors across the lifespan shape biological aging, influencing health and disease decades later. As researchers who use epigenetic clocks in our work, we have found them to be highly informative tools when studying large numbers of people. But these clocks can provide faulty results at the individual level, and they do not meet the standards required of common medical tests.

What are epigenetic clocks?

Measuring reversible chemical changes to DNA, known as epigenetic marks, can provide information about how your body is aging.

Using DNA obtained from routine blood draws, researchers can measure millions of these epigenetic marks in an individual. Running statistical algorithms on this information can produce a single value that represents that person’s epigenetic age, analogous to chronological age.

Epigenetic clocks work because the chemical marks on DNA can shift over time and are influenced by lifestyle, stress and the environment. These changes capture aspects of aging that chronological age alone may not reflect.

In this way, epigenetic clocks help scientists identify the experiences, exposures and behaviors that may accelerate or slow biological aging.

Not for individual health decisions

Why can’t epigenetic clocks provide reliable results about biological age for individual people?

First, there are dozens of different types of epigenetic clocks, each designed for a specific purpose. Some are used to predict a person’s age, while others are used to predict how fast someone is aging or how many years until they die. These different clocks do not always agree with one another, even when used on the same person.

Second, epigenetic changes are dynamic, making age predictions sensitive to short-term fluctuations in diet, environmental exposures, illness, time of day and other transient factors. As a result, estimated age could vary substantially depending on when someone is tested.

Third, constructing epigenetic clocks is technically challenging, and there is no established gold-standard method for generating clocks across laboratories. For example, testing epigenetic age in saliva versus blood samples can yield substantially different results for the same person. The technologies used to measure epigenetic marks have also evolved over time and will likely continue to improve. As these methods change, the original algorithms designed for specific measurement platforms may not perform the same way.

Fourth, scientists do not universally agree on what aging means, in part because it is a very complex process. Reducing that complexity to a single number, such as an epigenetic age, can be misleading.

Finally, epigenetic clocks are influenced by a person’s history of trauma, discrimination and early life adversity. This makes their use at the individual level potentially problematic. On average, marginalized communities tend to show signs of accelerated aging when assessed with epigenetic clocks. If insurance companies began using epigenetic age estimates to set premiums, many people could face higher costs for biological differences shaped by circumstances beyond their control, potentially deepening existing health disparities.

Studying how aging unfolds over time

While epigenetic clocks are not appropriate tools for individual health decisions, this does not mean they lack value.

Researchers have used epigenetic clocks to discover lifestyle habits that can, on average, slow down aging. Some examples include reducing daily calorie intake, exercising regularly, maintaining a healthy diet, getting enough sleep and avoiding smoking.

Epigenetic clocks can also help test new drug therapies aimed at slowing down specific aging processes. For example, researchers have shown that rapamycin, a drug connected to various aging processes, can reduce the epigenetic age of human skin cells. There is also some evidence that a treatment designed to regenerate the thymus may slow or even reverse epigenetic aging after one year of treatment. However, researchers have seen these effects only when looking at groups rather than individuals.

Epigenetic clocks are helping scientists advance scientific research on the aging processes, but they aren’t medical tests to measure individual health. In the future, epigenetic measurements may play a useful role in guiding personal health decisions. But for now, epigenetic clocks sold as biological age tests are best used and refined by researchers who are studying populations rather than individual people.

Idan Shalev receives funding from The National Institutes of Health.

Abner Apsley receives funding from the National Institutes of Health and the National Science Foundation.

Over the last two months, refineries and fuel storage facilities around the world have caught fire due to war (Russia) or accident (Australia, the United States, India and Mexico), adding more pressure to stressed oil and gas supply chains.

Global production of refined oil is normally around 100 million barrels a day. But this is under real strain. When Iran closed the Strait of Hormuz in February, it prevented 25% of global seaborne oil exports leaving the region. Iran also responded to strikes by the United States and Israel by launching attacks on oil and gas infrastructure in neighbouring states.

Ukraine’s recent attacks on Russian oil refineries have driven Russian output 12% lower than last year’s figures.

But while the spate of accidental refinery fires around the world only affect a small percentage of global output, they amplify the impact of the bigger supply shocks flowing from the Iran war.

This year’s unprecedented energy crunch has exposed deep structural weaknesses in how the global oil system operates – and how easily it can be disrupted. Refineries have become targets in war, while poor maintenance or accidents point to systemic stresses.

How refineries became a target

This year, oil refineries have become targets in two wars. Refineries and energy infrastructure have been targeted in previous conflicts. But advances in drone technology and intelligence have made attacks cheaper and more effective. It’s now possible to hit specific distillation columns or fuel storage tanks within a refinery.

The Russia-Ukraine war is now well into its fourth year. Ukraine has relied heavily on drones for defence and, increasingly, attack. Successive drone strikes on Russia’s Black Sea Tuapse refinery have done significant damage. Earlier strikes hit refineries in Perm and Orsk.

One of Iran’s main targets has been the oil and gas infrastructure of neighbouring Gulf States. Missiles, shrapnel and drones have hit refineries, fuel storage facilities and oil tankers. Fuel exports from the world’s biggest oil and gas region have slowed to a trickle.

Ukraine and Iran’s attacks on oil infrastructure show oil assets are no longer just civilian infrastructure. They can be instruments of economic warfare. Attacks are designed not just to cause local damage, but to create wider market disruptions and trigger sustained economic pressure. For Ukraine, the goal is to weaken Russia, economically and strategically. For Iran, the goal is to exert influence over the region and drive up oil prices to pressure the US to negotiate.

Australia’s refinery fire points to fragility

Fire is a key vulnerability for refineries and fuel storage facilities.

In mid-April, a fire broke out at one of Australia’s two remaining refineries. The fire forced petrol production at Viva’s Geelong refinery to be cut to 60% of normal production and diesel and jet fuel production to be cut to 80% until repairs are complete.

The cut to domestic refining capacity was “a setback”, according to federal Energy Minister Chris Bowen. Australia faces a real challenge on fuel, given limited local capacity and a heavy reliance on imported liquid fuels from overseas refineries in Asia. Unfortunately, the fire in Geelong added to the strain on fuel due to already reduced supply.

Refineries under strain globally

Over the last two months, fires have damaged a number of oil refineries.

India: A fire broke out at India’s large new Pachpadra refinery a day before it was to open. Initial reports suggest a leaking valve was to blame.

Mexico: Two fires have broken out at the troubled Dos Bocas refinery in Tabasco in recent weeks. The flagship state-owned refinery was meant to help Mexico cut dependence on fuel imports and boost energy sovereignty, but production targets have not been hit. The fires have worsened the situation.

United States: In March, a large explosion damaged the Valero Port Arthur Refinery in Texas, spreading toxic smoke throughout nearby communities.

Risk multipliers

This year’s spate of oil refinery fires have taken place as the world grapples with the much larger disruption caused by the US-Iran conflict.

These smaller incidents act as risk multipliers, amplifying the impact of the Iran war. The global energy system is already under pressure from geopolitical fragmentation, strained supply chains and contested shipping routes.

What they show is how vulnerable our energy systems are to disruption – even outside a war zone.

Aging infrastructure, reduced maintenance and increasingly complex systems mean even small fires or unit failures can escalate into significant supply disruptions.

During the first big oil shocks of the 1970s, the oil market was much less interconnected. Today’s oil system now has fewer backups and higher complexity, leaving it even more exposed to disruption, whether by accident or on purpose. Localised shocks can ripple further.

The 2026 energy crisis isn’t only a story about conflict in the Middle East. It’s also about a global energy system running on fumes. We should see news of a refinery fire not as an isolated industrial event – but as a sign of system under strain.

Meredith Primrose Jones does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.