Study finds women keep best friends into their 40s and beyond as men lose most close ties in their 20s

A study of 757 UK adults finds women are more likely to report having a lifetime best friend and to maintain close confidants into their late 40s, while men shed most of their close friends in their 20s. Researchers say the gender gap in long-term friendships persists even as people form marriages and other social commitments, underscoring distinct social patterns in how men and women cultivate and prune their inner circles.

The research, led by Professor Robin Dunbar of Oxford University and published in Evolution and Human Behaviour, quantified how many people each participant would name as a best friend and how those friendships aligned with gender. The study found that about three-quarters of women reported having a best friend, compared with 59 percent of men. Among women, 81 percent of best friends were female, while among men, 73 percent of best friends were male. These findings point to a tendency for both sexes to form and maintain same-sex best friendships, with opposite-sex best friendships becoming more common later in life for some.

The study also reveals detailed timelines for when people form their closest attachments. Women tended to have their best friends from their late teens onward, with many reporting that their closest confidantes had been in their lives since around age 18. Men, by contrast, reported their closest male friends were often those they met around age 19. The data suggest that men’s social networks contract noticeably after major life transitions, particularly marriage, whereas married women maintain a broader web of intimate relationships.

As participants aged, the patterns shifted further. The researchers found that men were more likely to say they had a best friend as they grew older, but this trend did not hold for women, for whom the likelihood of naming a best friend tended to wane as they entered and progressed through midlife. The authors note that the timing aligns with broader life-stage changes, including family responsibilities and shifts in daily routines.

Opposite-sex friendships followed different trajectories from same-sex ties. Women tended to meet their male best friends around the mid-20s, on average, while men tended to form female best friendships a few years later, around age 26. The researchers emphasize that these opposite-sex ties often require more deliberate nurturing and may be influenced by romantic relationships and social environments such as workplaces or clubs.

In terms of the structure of social networks, the study found men’s inner circles to be relatively homogeneous, with close friends frequently drawn from similar social or occupational groups, such as workplaces or sports teams. By contrast, women’s inner circles tended to be larger and more varied, reflecting the paper’s conclusion that women’s social worlds often centre on personalized, one-on-one connections rather than club-like affiliations based on shared status or identity. Prof Dunbar framed this contrast by noting that the male social world is often more impersonal and club-like, while women’s networks revolve around personal ties and direct interpersonal bonds.

The data also showed notable gender differences in overall reliance on close friends within romantic relationships. Among men, being in a supportive romantic relationship correlated with a smaller inner circle, suggesting that a partner can become more important than friendships for some men. Women, in contrast, tended to keep larger networks even when in committed relationships, reflecting a tendency to balance intimate partnerships with broader social connections.

The study’s broader implications touch on how social habits shape well-being across the lifespan. While the research is descriptive and based on a specific cohort, its authors say the patterns align with long-standing theories about gendered approaches to social connection. Dunbar and colleagues caution against overgeneralizing to all populations, noting that the sample is limited to 757 adults in the United Kingdom. Nevertheless, the findings contribute to a growing body of evidence that gender differences influence not only who people consider a best friend, but also how those relationships evolve as life circumstances change.

For readers seeking to understand their own social lives, the study offers a reminder that friendships often follow distinct developmental trajectories. Women’s friendship networks may endure through later life stages, including parenthood and grandparenting, while men’s networks may narrow earlier as family and work commitments take precedence. The research highlights the enduring importance of close relationships for mental and emotional health, regardless of gender, while also acknowledging the varied paths people travel as they age and form new roles.