Examining Protein Requirements for Pre-Menopausal Women Post-Exercise

Women are often bombarded with various diet, health, and lifestyle advice, yet exercise science research has historically underrepresented female-specific responses and needs. Recent findings from the University of Otago—Ōtākou Whakaihu Waka study delve into how pre-menopausal women respond to post-exercise protein supplementation.

Led by researcher Marc Murray, the study focused on assessing the influence of protein intake after resistance and high-intensity interval training sessions on muscle development and growth hormones, particularly Insulin-like Growth Factor 1 (IGF-1). IGF-1 plays a crucial role in muscle protein synthesis, which is vital for muscle repair and growth.

The research emphasized the importance of including pre-menopausal women in exercise science because much of the existing guidelines are based predominantly on male or mixed-sex data, potentially overlooking hormonal and physiological differences. Estrogen and progesterone in women can influence muscle protein turnover and their unique responses to training and nutrition.

In the study, 27 healthy, untrained women aged 18 to 50 participated over 12 weeks, engaging in bi-weekly upper-body resistance workouts and thrice-weekly high-intensity cycling sessions. Post-exercise, half of the women received a whey protein supplement containing 24 grams, while the other half consumed a low-protein, 3-gram drink with the same caloric value.

Results showed significant improvements in strength and lean muscle mass across all participants, with no significant difference observed between the protein-supplemented group and the control group, nor notable changes in IGF-1 levels. This suggests that, at least over a 12-week period, post-exercise protein supplementation may not have an immediate differential effect on muscle adaptation in pre-menopausal women.

However, researchers noted that longer-term studies might reveal more pronounced effects, as 12 weeks could be insufficient to observe the full impact of protein intake. Factors such as diet and timing of workouts relative to meals could also influence outcomes. Nonetheless, protein supplements remain a convenient way to help meet daily protein requirements, especially for women with suboptimal dietary intake.

Murray concluded that untrained women can safely follow exercise guidelines primarily based on male data and still achieve significant strength and muscle gains. The study underscores the necessity for more research into women’s physiological responses to training and nutrition, addressing the historical under-representation in health science research.

For more details, see the full study: Post-Exercise Whey Protein Supplementation: Effects on IGF-1, Strength, and Body Composition in Pre-Menopausal Women, a Randomised Controlled Trial, Nutrients (2025). Source: https://medicalxpress.com/news/2025-09-pre-menopausal-women-protein.html