For decades, most medical and biological research has been conducted primarily on male volunteers and male animals in laboratory studies. One of the main reasons was convenience - male hormone levels are more stable, whereas female hormones shift across the menstrual cycle, introducing variability that researchers historically preferred to avoid. 

But that convenience has come at a cost. 

When treatments are developed and tested mainly in males, the results don’t always translate well to female physiology. This means that women have often been prescribed medications or therapies that were never fully tested on their biology. In some cases, women have experienced more side effects, reduced effectiveness, or entirely different outcomes than men. 

As we learn more, it’s becoming clear that male and female bodies age differently too. And new anti-ageing treatments may need to take these differences into account. 

A new study published in the journal Ageing shows exactly why. 

The researchers discovered a combination of two drugs that extended lifespan in frail, elderly male mice by an impressive 73 percent from the start of treatment while also improving their mobility, endurance and memory. 

However, the same therapy did not provide the same benefits to female mice. 

They tested oxytocin, which is known to support tissue repair, along with another drug known as OT+A5i, which blocks a key pathway involved in regulating cell growth, differentiation, and death. 

The study involved 25-month-old mice which is roughly equivalent to a 75-year-old human. 

In male mice: 

• Lifespan increased by 73 percent from the start of treatment.
• Median lifespan increased by 14 percent.
• Risk of death at any time decreased three-fold.
• Endurance, grip strength, and agility improved.
• Short-term memory improved.
• Blood biomarkers shifted toward younger, healthier levels.

But in female mice: 

• No significant extension of lifespan.
• No consistent improvements in strength or memory.
• Blood biomarkers did not shift in the same way.

Researchers suggest several possibilities for the difference: 

• Female inflammatory signalling pathways differ from males
• Hormonal environments change ageing differently in men and women
• The interaction between oxytocin and TGF-beta networks may not play the same role in female tissues 

This highlights the point that ageing is not identical in men and women, and treatments to slow ageing may need to be tailored accordingly.