Recent research presented at The Menopause Society 2025 Annual Meeting in Orlando has shed new light on the weight loss potential of GLP-1/GIP dual-receptor agonists in postmenopausal women. Specifically, it found that the weight loss experienced by postmenopausal women using menopausal hormone therapy (MHT) was greater compared to those who did not use MHT.
Tirzepatide’s Effect on Midlife Weight Gain
Tirzepatide, a medication that targets both GLP-1 and GIP receptors, has emerged as one of the most effective treatments for weight management. For women experiencing weight gain during midlife, a period often linked to an increased risk of cardiovascular disease, tirzepatide could be a promising solution. Dr. Regina Castaneda, a postdoctoral research fellow at Mayo Clinic, highlighted the need to understand how different stages of the reproductive life cycle and the use of hormone therapy impact treatment outcomes.
Study Design and Results
In this study, researchers analyzed a cohort of 521 women, with an average age of 50, and separated them into four groups of 40 women each. These groups were based on menopausal status and use of hormone therapy. The participants’ baseline characteristics, such as BMI, diabetes status, and history of weight loss medications, were matched across the groups.
- Premenopausal women: Average age of 37 years.
- Perimenopausal women: Average age of 49 years.
- Postmenopausal women not on hormone therapy: Average age of 59 years.
- Postmenopausal women on hormone therapy: Average age of 56 years.
Over 18 months, all groups experienced significant body fat reduction with tirzepatide, but there were variations in the amount of weight lost. The premenopausal group lost an average of 18.7% of their body fat, while the perimenopausal group lost 18.6%. Postmenopausal women on hormone therapy had the most substantial loss, with a 19.9% reduction in total body fat. However, postmenopausal women not taking hormone therapy lost only 15.6% of their body fat, a statistically significant difference (P = .02).
Surprising Findings: Hormone Therapy’s Role in Weight Loss
Dr. Karen Adams, a clinical professor at Stanford Medicine, commented on the study’s unexpected findings. She noted that while tirzepatide has been shown to induce weight loss, the data indicated a notably greater response in postmenopausal women using hormone therapy. This highlights the potential role of menopausal hormone therapy not only in managing menopausal symptoms but also in enhancing weight loss efforts.
Possible Explanations for Enhanced Weight Loss
Several theories have been proposed to explain the enhanced weight loss observed in postmenopausal women on hormone therapy. One possibility is the “healthy user bias,” where women using hormone therapy might also engage in healthier lifestyle habits. These could include more regular exercise, potentially driven by better management of vasomotor symptoms like hot flashes.
Additionally, preclinical studies in mice have suggested that estrogen could interact synergistically with GLP-1 signaling, further amplifying the weight loss effects of tirzepatide. However, these findings are still exploratory and require further investigation in human trials.
Caution and Considerations
It is important to note that while the study indicates an association, it does not establish causation. Dr. Castaneda emphasized that menopausal hormone therapy is not indicated solely for weight loss, and the decision to use both hormone therapy and weight-loss medications must be individualized. Dr. Adams reiterated that menopausal hormone therapy should not be prescribed solely for weight management but noted that its potential benefits in combination with GLP-1 agonists could improve weight loss outcomes for some women.
Future Research Directions
This study raises critical questions about the interaction between menopausal hormone therapy and weight loss treatments. Future research should explore how different forms of hormone therapy impact weight loss with tirzepatide and investigate the long-term outcomes of combining the two treatments.
Conclusion
Midlife weight gain is a common challenge for many women, particularly during menopause, and it is associated with increased health risks. This study provides valuable insights into how GLP-1 receptor agonists like tirzepatide may be more effective for women undergoing hormone therapy. While these findings are promising, they underscore the need for individualized treatment plans and further research to optimize weight management strategies for postmenopausal women.
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