Women and Men Share Similar Potential for Muscle Growth Through Weight Training

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How Testosterone Influences Baseline Strength and Growth

The physiological gap in muscle size between sexes is primarily established early in life. Testosterone acts as a primary driver for muscle mass during development, creating a distinct starting point for adults. “Testosterone increases muscle mass in boys, and so you get an adult 20-year-old man and an adult 20-year-old woman, and there’s going to be differences in baseline muscle size and strength,” Lauren Colenso-Semple, researcher and science communicator, via National Geographic While these baseline differences exist, the body’s response to training is more universal. Once a resistance program begins, the gap in growth potential narrows. A 2025 meta-analysis published in PeerJ found that the capacity for muscle growth is similar across both sexes. Colenso-Semple noted that the trajectory of muscle size and strength gains is “very, very similar in men and women” when lifting weights.

The Role of Short-Term Hormone Spikes vs. Long-Term Balance

A common misconception in fitness circles is that “hormone spikes” immediately following a workout are the primary drivers of muscle growth. Resistance training does trigger temporary increases in several hormones, including Growth hormone (GH), Insulin-like growth factor-1 (IGF-1), and testosterone. However, LinkedIn reporting indicates that these short-term increases do not predict how much muscle a person will actually build. The direct answer to whether these brief spikes build muscle is no. The real influence of hormones lies in the overall hormonal environment and the balance between two competing processes:

Muscle Protein Synthesis (MPS): The process of building new proteins.

Muscle Protein Breakdown (MPB): The process of breaking down old proteins.

Muscle growth occurs only when the body builds more protein than it breaks down. Hormones act as the regulatory system for this balance. For instance, insulin helps muscles retain protein, while cortisol promotes the breakdown of protein.

Testosterone as a Cellular Signal

Testosterone does not build muscle in a vacuum; it functions as a signaling molecule. Produced primarily in the testes for men and in smaller amounts in the ovaries and adrenal glands for women, it targets specific androgen receptors within muscle cells. These receptors act like switches. When testosterone binds to them, the muscle cell receives instructions to build more proteins and increase strength following a workout. In this capacity, exercise signals the need for adaptation, and testosterone ensures that the message is effective and sustained over time. The importance of this hormonal maintenance is evident when levels drop. In conditions of very low testosterone, individuals often face increased fatigue, slower recovery, and a loss of muscle mass and strength. When levels return to normal, muscle mass typically increases again.

The Gap in Women’s Strength Training Adoption

Despite the evidence that women can achieve relative gains similar to men, a significant gap remains in how women utilize strength training. This is often attributed to outdated advice suggesting women must “train around” their hormones or avoid heavy weights. The lack of adoption has public health implications. Resistance training is a critical tool for preserving bone density, supporting healthy aging, and improving cardiovascular health. Metric Stat U.S. adult women meeting federal muscle-strengthening guidelines (2020) 27 percent While hormonal fluctuations can affect how a workout feels on a daily basis, there is little evidence that women require entirely different training programs to achieve fitness, strength, or muscle growth. Consult your healthcare provider before starting a new high-intensity strength training program.

Find more reporting in our Health section.