Hypertrophy in relation to striated skeletal muscle refers to the increase in muscle mass through enlargement of muscle cells, a physiological adaptation process that is primarily triggered by strength training, stress stimuli, and hormonal stimulation .
For many men, hypertrophy is associated with aesthetics or bodybuilding. But muscle growth plays a far broader role in general health, metabolism, hormone regulation, and everyday performance .
Especially in the context of testosterone, insulin sensitivity and stress regulation, hypertrophy is a highly relevant factor in men's health - not only in the gym, but in the overall lifestyle.
What happens during hypertrophy?
During intense physical exertion (e.g., weight training), microscopic damage occurs in the muscle fibers. The body reacts to this with repair and adaptation processes by:
- the muscle fibers thicken (not increase in number)
- incorporates more contractile proteins (e.g., actin, myosin)
- the cross-sectional area of the muscles increases
- and thus increases resilience
Simply put: The body prepares for future stresses by making the muscles bigger, stronger, and more resilient .
What forms of hypertrophy are there?
There are broadly two types:
- Myofibrillar hypertrophy : Enlargement of the contractile units in the muscle leads to increased strength. Develops through heavy loads and low repetitions.
- Sarcoplasmic hypertrophy : An increase in cell volume due to the accumulation of fluid, glycogen, and enzymes leads to increased muscle volume. This results from higher volume and medium repetition ranges.
For lasting success, a combination of both stimuli is often beneficial.
How is hypertrophy triggered?
To achieve effective muscle growth, certain conditions must be met:
- Progressive overload = increasing training stimuli over time
- Mechanical stress - through controlled repetitions under load
- Metabolic stress - e.g., through repetitions near muscle failure
- Sufficient regeneration – at least 48–72 hours per muscle group
- Hormonal status - including testosterone, growth hormone, IGF-1
- Calorie surplus + sufficient protein
Sleep, stress, and micronutrients (e.g., magnesium, zinc, vitamin D) also influence the ability to hypertrophy.
What role does testosterone play?
Testosterone is one of the most important anabolic stimulants for muscle growth. Testosterone:
- stimulates protein biosynthesis
- inhibits muscle-wasting processes (catabolism)
- promotes regeneration
- Increases training adaptation and motivation
Low testosterone levels can lead to a lack of hypertrophy, poor recovery, and loss of strength, even with training.
In addition, cortisol (stress hormone) and SHBG (binds testosterone) also influence actual muscle growth.
Which training methods promote hypertrophy?
- Classic strength training with 6–12 repetitions per set
- 3-5 training sessions per week , depending on recovery capacity
- Compound exercises such as squats, bench press, deadlifts
- Eccentric loading (e.g., slowly lowering the weights)
Bodyweight training, machines, free weights or resistance bands can also be effective; the crucial factor is the progressive stimulus.
What blocks muscle growth?
- Too few calories or protein
- Chronic stress / excessively high cortisol levels
- Poor sleep
- Low testosterone levels
- Overtraining or insufficient stimulus
- Alcohol, smoking, micronutrient deficiencies
Furthermore, an imbalanced hormonal status can lead to stagnation despite training - especially if symptoms such as fatigue, loss of libido or muscle loss occur at the same time.
Other muscle groups can also hypertrophy, for example, the heart muscle. However, this can have negative health consequences.
Conclusion
Hypertrophy is far more than just muscle building for aesthetics; it's a key component for health, metabolism, hormonal balance, and performance . Those who strategically apply stimuli, pay attention to nutrition and recovery, and understand their own hormonal makeup will benefit sustainably, both physically and mentally.
Tip: If you train regularly but don't see any progress, or feel tired and drained despite your discipline, a hormonal imbalance could be the cause. Adon Health's premium hormone analysis provides you with all the relevant values, including free testosterone, cortisol, LH, and FSH – conveniently from home. This way, you can see if your body is ready for real muscle growth.
Listen to our podcast episode with Dr. Sascha Gail on the topic "What men really need to know about training" or read the blog article on strength and endurance training .
