Everyone wants to live longer. But not just longer. We want more good years, free from disease and disability. That’s why longevity science has exploded into a 900 billion dollar industry. Supplements promise to reverse aging. Clinics offer “anti-aging protocols.” Influencers share their elaborate daily routines.

But here’s the question nobody selling you something wants to answer honestly: Does any of it actually work?

The truth is more complicated than either the hype or the skepticism suggests.

A Real Science With a Big Idea

First, the good news: longevity science is legitimate. It’s not snake oil or wishful thinking. Scientists have identified real cellular pathways that control aging with names like mTOR, AMPK, and sirtuins. They’ve moved from ancient “elixirs of life” to actual molecular biology. This is a genuine scientific field.

The core idea driving this research is called the “geroscience hypothesis.” It’s actually pretty simple: instead of treating diseases one by one after they appear, what if we could target the aging process itself? If aging is the root cause of heart disease, cancer, Alzheimer’s, and diabetes, then slowing aging might prevent or delay all of them at once.

That would be revolutionary. It would flip medicine from chasing diseases to preventing them.

Worms and Mice Are Living Longer. We’re Not Sure About Humans.

Here’s where things get tricky. Scientists have gotten remarkably good at extending the lives of nematodes and lab animals. The evidence is compelling:

A 2020 study by researchers at the MDI Biological Laboratory and the Buck Institute for Research on Aging achieved a 500% (5X) increase in the lifespan of Caenorhabditis elegans (roundworms) by simultaneously altering two cellular pathways: the insulin signaling (IIS) pathway and the TOR (target of rapamycin) pathway. Caloric restriction (eating significantly less) increases mouse lifespan by 10 to 40% and delays age-related diseases. Rapamycin, an immune-suppressing drug, extends median mouse lifespan by 154 to 249 days. Senolytic drugs, which clear out damaged “zombie cells,” reduce organ dysfunction and extend lifespan in animals. Metformin, a cheap diabetes drug, improves lifespan in some animal species.

This isn’t pseudoscience. These are real results, replicated across different labs and different species.

But here’s the problem: no longevity intervention has been proven to extend human life. Not one. Zippo. Zero. Nada.

Mice aren’t tiny humans. What works in a lab doesn’t always translate to us. And proving something extends human lifespan takes decades of research we haven’t done yet.

The Human Evidence: Promising But Limited

So what do we actually know about humans?

Caloric restriction has the strongest evidence. Studies show a 15% reduction in death risk among adults with obesity and diabetes who significantly reduce calories. Their biological aging markers slow down too.

Exercise and healthy diets (like the Mediterranean diet) are linked to reduced heart disease, better blood vessel function, and younger biological age. This isn’t surprising, but it’s worth noting: the boring advice your doctor gives you actually has science behind it.

Rapamycin and its relatives have shown they can improve vaccine effectiveness in older adults, a sign the drug might be boosting immune function. But that’s a long way from proving it extends life. Brian Johnson, the famous self bio-hacker recently reported accelerated aging based on his own use of rapamycin. 

Senolytics (the zombie cell clearing drugs) appear safe in early human trials. But whether they actually make people healthier? We don’t know yet.

The Metformin Mystery

Metformin deserves special attention because it’s been the poster child for longevity drug research. It’s dirt cheap, incredibly safe, and millions of diabetics have taken it for decades. Early studies suggested diabetics on metformin outlived even non-diabetics, which made scientists think the drug might be doing something beyond controlling blood sugar.

But recent reviews have delivered disappointing news: metformin generally hasn’t shown its anticipated benefits in clinical trials with non-diabetic people.

The definitive test would be the TAME trial (Targeting Aging with Metformin). Scientists designed it to see if metformin can delay age-related diseases in healthy older adults. But here’s the frustrating part: the trial has been stuck in funding limbo for years. It needs $45 to $70 million. Because metformin is a generic drug, no pharmaceutical company stands to profit from proving it works. So the money hasn’t materialized.

This reveals a structural problem in longevity research: the most promising drugs are often off-patent, which means nobody has a financial incentive to test them properly.

The NAD+ Supplement Craze: Hype Outpacing Evidence

Walk into any health store and you’ll find NMN and NR supplements claiming to boost NAD+ and reverse aging. The premise sounds scientific: NAD+ is crucial for cellular energy, and levels drop as we age. Restore NAD+, restore youth. Right?

Not so fast.

Yes, these supplements do raise NAD+ levels in your blood. But this is crucial: a systematic review found that most clinically relevant outcomes weren’t different between supplement and placebo groups. Researchers concluded that “an exaggeration of the benefits of NMN supplementation may exist in the field.”

One trial gave older adults NR supplements and boosted their NAD+ levels by 139%. Impressive! But their cognitive function? Unchanged. No difference from placebo.

This is the key lesson: changing a biomarker isn’t the same as improving health. Just because a number goes up doesn’t mean you’ll live longer.

Senolytics: Cool Science, Unproven Benefits

Senolytics are one of the most exciting areas in aging research. The idea: as we age, damaged cells stop dividing but refuse to die. These “zombie cells” stick around, spewing inflammatory chemicals that poison neighboring cells. Clear them out, and tissues might work better.

The drug combination of dasatinib (a cancer drug) and quercetin (a plant compound) has shown promise in small studies. Patients with kidney disease had fewer senescent cells and better physical function. Patients with lung fibrosis showed improvements too.

But a 2024 study threw a curveball: people taking these senolytics actually showed increased aging on some biological clocks, plus shorter telomeres. The picture is more complicated than “kill zombie cells, get younger.”

Larger trials are underway. Until they finish, senolytics remain promising but unproven.

The Credibility Crisis

Longevity science has a credibility problem. Exaggerated claims are everywhere, from supplement marketing to social media to occasionally even scientists overselling preliminary findings.

Surveys show people are much more willing to try exercise (66% acceptance) and supplements (82%) than drugs like metformin (26%) or rapamycin (10%). This skepticism reflects something real: the absence of long-term proof that these drugs work for healthy aging.

Even iconic concepts face scrutiny. The famous “Blue Zones,” regions supposedly packed with centenarians, are under attack from researchers who found that when birth certificates became mandatory, centenarian counts dropped sharply. When Greece verified pension recipients, 70% of supposed centenarians turned out to be dead. The lifestyle lessons from these communities may still be valuable, but the underlying data is shakier than advertised.

A Reality Check on Living to 100

A sobering 2025 study found that no generation born after 1939 is expected to reach an average lifespan of 100. The dramatic life expectancy gains of the early 20th century, mostly from reducing childhood deaths, have slowed dramatically. Future improvements depend on breakthroughs in adult health that haven’t happened yet.

So What Actually Works?

If you want to live longer and healthier based on current evidence, here’s the honest answer:

What has strong evidence: Sleep, exercise, social connection, and a plant-forward diet. Boring? Yes. Proven? Also yes. A 2025 study confirmed that strong social ties literally slow biological aging by reducing chronic inflammation.

What has moderate evidence: Caloric restriction (with caveats about sustainability). Mediterranean and DASH diets. Vitamin D supplementation (one study showed benefits equivalent to nearly three years of reduced biological aging).

What has promising but incomplete evidence: Metformin, senolytics, NAD+ precursors. The scientific rationale exists. The human proof doesn’t. Yet.

What has mostly hype: Most supplements marketed as “anti-aging.” The carnivore diet. Anything promising dramatic results from a single intervention.

GLP-1 drugs like Ozempic may be the most evidence-backed pharmacological intervention with longevity relevance right now. But they were developed to treat diabetes and obesity, not aging itself.

The Bottom Line

Longevity science is real. The biology of aging is increasingly understood. Nematode and animal studies have produced genuine breakthroughs. Multiple large trials are underway that could change the picture in the coming years.

But the honest assessment today is this: we have no pill that’s been proven to extend human life. The clinical translation of this promising research remains constrained by lack of validated interventions, regulatory frameworks, and standardized biomarkers.

The field has moved from pseudoscience to legitimate molecular biology. That’s real progress. But anyone claiming to have cracked the code of human aging is selling something other than certainty.

For now, the best longevity strategy remains the one your grandmother probably told you: eat well, move your body, sleep enough, and stay connected to people you love.

Also Medome has been proven among tens of thousands of users to help you stay on top of your health. www.medome.ai

The science may eventually give us more. But it hasn’t yet.