New research reveals there may be merit in one piece of age-old folk wisdom: that friends keep you young.

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It’s no secret that having strong relationships is associated with having better health. But according to an October 2025 study published in Brain, Behavior, & Immunity – Health, these benefits seemingly run all the way down to our DNA.

Working with data from over 2,000 American adults, the research team from Cornell, Stony Brook and Harvard found that social connection is so much more than just the key to a richer, more meaningful life. Amazingly, the results suggest that relationships may make life longer, too. Here’s a breakdown of the study’s findings.

Measuring Aging At The Cellular Level

Modern discussions regarding mental health often tend to take a reductive view on friendships and romantic relationships to a simple equation. The equation here is purported to be all too simple: that loneliness is harmful, and companionship is protective.

However, the 2025 study sought to look more deeply at the role that relationships play in our lives. Instead of assessing only whether or not people currently felt supported by their relationships, the research team tracked the cumulative impact of social experiences — from childhood up until adulthood.

Anthony Ong, the lead author of the study, describes this as “cumulative social advantage.” Put simply, this implies that social advantages don’t usually stem from a singular friendship, nor from having a particularly supportive spouse. Rather, it suggests that our social resources tend to stack up throughout the entirety of our lives.

From this perspective, almost every relationship you’ve ever had — and likely will ever have — matters. Did your parents provide warmth and security when you were growing up? Do you feel a sense of community with those around you in your neighborhood? Have you found a sense of belonging within a faith group, or other collective? Does your partner, your friends and or your family offer you consistent emotional support?

Once the researchers started to combine these many different social factors, they found that higher scores were consistently tied to healthier biology.

To assess this, the researchers looked at the participants’ “epigenetic clocks.” As the name implies, these are estimates of an individual’s biological age, derived from the chemical patterns that are encoded within our DNA. These clocks can, in essence, reveal how fast a person is aging biologically, which may not necessarily align perfectly with their actual age.

The team also measured markers of systemic inflammation — substances in the blood that rise when the immune system is chronically switched on, which are well-known predictors of heart disease, diabetes and many other age-related conditions.

Consistently, the findings showed that participants who were biologically “younger” had much stronger lifelong social connections. Moreover, their social advantage also made a positive difference in terms of inflammation, too. Overall, their cells had seemingly held up better against the slow grind of time.

Social Life As A Long-Term Investment

It may sound abstract, but the researchers likened social connection to a retirement account. As Ong explained in an interview with PsyPost, “The earlier you start investing and the more consistently you contribute, the greater your returns.”

In other words, you won’t see payoff from a single “deposit” into your social account — for instance, from one family dinner, one brunch with your friends or one date night with your partner. But should you make an effort to invest steadily, the returns will compound. This means that, by midlife, the effects of having supportive parents, strong friendships and a sense of community will be palpable.

The “returns” will be most noticeable in your emotional resilience. But, it will also leave you with younger cells and a calmer immune system, even if you aren’t conscious of it.

The concept of “aging well” takes on an entirely new meaning in light of these findings. Before, we understood it as a matter of eating vegetables, exercising regularly, drinking water and ensuring regular check-ups with a physician. Now, however, we know that it’s also ensured when we curate a strong list of social connections over time.

Ong encapsulates this well, explaining that, “It’s not just about having friends today; it’s about how your social connections have grown and deepened throughout your life.”

However, with this in mind, there’s also a more sobering side to these findings — in that not everyone has the same opportunity to build this social “retirement account.” Our access to supportive relationships is shaped profoundly by factors like our family background, our community resources, our socioeconomic status and our cultural context.

So, in other words, just as financial wealth accumulates unevenly in an unequal society, social wealth does, too.

A nurturing home with access to safe neighborhoods and strong community networks will aid you in accumulating layers upon layers of advantage over decades. Someone who grew up in neglectful circumstances or in a socially fragmented environment, on the other hand, will face a compounded disadvantage. The biological differences revealed in this study suggest that these social inequalities are visible even within the cells of our bodies.

The 2025 study’s grounding in hard biological outcomes is what makes it particularly compelling. There’s already a good chance that you’ve been told that “friends keep you young.” It’s been around in pop psychology for years, but, now, we have measurable proof of it.

Social connectedness is one of the most important parts of living a meaningful life. Take this science-backed test to find out how connected you feel to others: Social Connectedness Scale