Women remain underrepresented in exercise and nutrition research, which is odd when you consider how many depend on structured training and thoughtful dietary choices to feel strong, energised and capable across different stages of life. That gap makes it harder for us as coaches to give advice that genuinely reflects women’s physiology. It also means that when a study appears that focuses exclusively on women, it should be taken seriously. A new systematic review and multilevel meta-analysis does exactly that, and it gives one of the clearest views yet of how multi-ingredient protein supplements work alongside structured exercise for female clients.
This kind of insight sits perfectly for anyone studying or working through a nutrition coach course, because it connects physiology with practical, everyday coaching. The findings also speak directly to professionals who lean into a women’s health approach as part of their broader fitness courses, especially those who prioritise resistance training.
Protein intake, nutrient timing and the basics of muscle recovery often pop up early in a nutrition course, and this review helps move those concepts from theory into application. The research team pulled together nine randomised controlled trials including 408 women aged 18 to 73, all following structured training programmes. Most completed resistance training, while others combined aerobic and resistance sessions.
The Research
The supplements used in the trials were multi-ingredient blends, not single sources of protein. Some included whey or casein. Others relied on soy. Several combined protein with leucine, creatine, vitamin D, carbohydrates or calcium. The researchers wanted to understand whether these blends supported muscle growth, strength improvements or changes in body composition when women trained consistently.
The review asked one core question: Does structured exercise paired with multi-ingredient protein supplementation support measurable improvements in women’s muscle mass and strength? The answer is encouraging, although it takes some unpacking.
The Findings
The combined results showed that pairing multi-ingredient protein supplements with structured exercise led to improvements in fat-free mass, muscle size and strength. The increase in fat-free mass averaged around 0.45 kg. It may seem small, but it reflects genuine positive change in muscle tissue. Hypertrophy also improved and the gains were statistically significant. Strength improvements sat in the moderate range, which aligns with earlier findings in male or mixed samples, but this is the first review to bring multiple trials together for women alone.
Alongside these gains, the review also made it clear what did not shift. Fat mass stayed largely the same. Body fat percentage did not move much. Waist circumference barely changed. Functional performance measures, such as sit-to-stand scores, remained stable. These outcomes help shape conversations with clients. Muscle responds well to high-quality protein intake and structured training. Fat reduction follows a different pathway and needs specific nutritional and behavioural strategies.
Why These Results Make Sense for Women
A bit of physiology helps explain the patterns in the data. Muscle protein synthesis depends heavily on leucine-rich protein sources. Women often benefit from more deliberate protein intake, partly because they generally have lower baseline muscle mass and partly because hormonal variations create more fluctuations across a month.
The multi-ingredient blends used in the trials included elements that naturally support training and recovery. Creatine supports phosphocreatine replenishment and training volume. Vitamin D plays a role in neuromuscular function and bone health, which matters even more for peri- and post-menopausal women. Carbohydrates assist with recovery and fuel availability. These additions create an environment where resistance training can have more impact.
Who Responded Best and Why
The review highlighted several factors that changed how well the supplements worked.
Age: Older women gained more fat-free mass. Younger women showed more pronounced strength improvements. Age influences training adaptation, and this study reinforces that understanding.
BMI: Women classified as overweight showed improvements. Women living with obesity did not experience the same level of change, which reflects the known issue of anabolic resistance.
Supplement Timing: Timing played a noticeable role. Taking supplements close to training sessions supported increases in fat-free mass. When supplements were taken with meals, strength improvements stood out more in the data.
Programme Duration: Programmes lasting longer than twelve weeks produced clearer and more consistent changes in both muscle mass and strength. This matches what no doubt we have all observed in practice. These adaptations need time.
Isocaloric vs Non-Isocaloric Designs: Results were stronger in studies where supplements added extra calories. This lines up with the recurring pattern seen in active women who unintentionally operate in a low-energy state. Energy intake influences muscle retention and training output.
How to Apply These Findings
These findings translate easily into practical coaching steps. Daily protein intake often works best between 1.2 and 2.0 g/kg/day for women who train regularly. Per-meal targets around 0.32–0.38 g/kg help stimulate muscle protein synthesis throughout the day. Many women fall short of these numbers, so tracking intake can reveal more than expected.
Multi-ingredient blends can support women who struggle to reach ideal protein intake through food alone, particularly those following vegetarian or vegan dietary patterns. These blends contain key nutrients for muscle health and may be helpful during heavier training blocks. Food should remain the foundation, but supplements can fill gaps as needed.
Training Structure That Works Well for Women
Most of the programmes in the review relied on three weekly training sessions using intensities between 60 and 85% of 1RM. This is a common approach when training women aiming to build muscle and strength. Whole-body or lower-body dominant training formed the base of each programme, using exercises such as squats, presses, rows, deadlifts and leg presses.
Aerobic or HIIT sessions can be added when goals include fat reduction or improved cardiovascular health. The review reinforces that resistance training is central when the aim is muscle size and strength.
Life Stages, Motivation and the Broader Health Picture
Beyond sets, reps and nutrient timing, the review touches on a bigger theme. Women face unique life-stage transitions that influence everything from training consistency to motivation. Physical activity often drops after adolescence and continues to decline through adulthood. Workload, caregiving and fatigue all play a part. During peri- and post-menopause, muscle loss accelerates, bone density drops and blood lipids change.
A steady routine of resistance training paired with consistent, high-quality protein intake becomes a strong foundation for healthier ageing. This pattern appears across multiple areas of women’s health research, not just in this meta-analysis.
This message can shape the coaching conversation in meaningful ways. Muscle contributes to metabolic health, bone strength, energy regulation and overall resilience. It gives women confidence and independence later in life. When goals shift from weight loss alone to long-term strength and capability, women often find a deeper level of motivation to keep going.
Final Thoughts
The review offers the straightforward message that when women follow structured strength training and support it with targeted, high-quality protein intake, often in the form of multi-ingredient blends, they see improvements in muscle mass and strength. The process suits women across a wide range of ages and training backgrounds. It encourages a steadier and more sustainable approach to health and wellbeing through every life stage.
Reference
- Zhou, C., Qiu, M., Zeng, Z., et al. (2025). Effects of multi-ingredient protein supplementation combined with exercise intervention on body composition and muscle fitness in healthy women: A systematic review with multilevel meta-analysis. Frontiers in Nutrition. Click here to review the full research article.
Step Into Coaching Women With Confidence
The Women’s Health & Exercise Specialist & Master Diplomas™ are designed for anyone who wants to step confidently into the fitness industry and build a career that truly supports women through every stage of life. They cover the physiology, training approaches and health considerations that matter most, from menstrual cycle awareness to peri- and post-menopause needs. We’ve also just released a brand-new version of the course created specifically for qualified personal trainers who want to deepen their expertise in female-focused coaching and offer a more informed, supportive service to their clients. This pathway gives you a clear, practical understanding of how to help women train well, recover well and feel strong throughout their lives.
Women’s Health & Exercise Specialist/Master™ – Distance Study, In-Person & Live-Virtual
