How muscle loss begins
It begins without warning. The stairs to the apartment feel steeper than they did a few years ago, the crate of drinks feels heavier, and getting out of the low armchair now requires some momentum.
In medicine, this process is called sarcopenia, after the Greek words for flesh and loss. From around age 50, one to two percent of muscle mass is lost each year. [3]
Muscle strength declines even faster, by one and a half to five percent per year depending on the muscle group. [3] The muscle therefore loses not only volume but also quality.
The legs are affected most severely: Their muscle strength decreases by about 3.2 percent per year, while that of the arms decreases by 1.5 percent. [3] The decline therefore begins exactly where walking, climbing stairs, and standing up depend on it.
Why muscle strength became the most important criterion
In 2019, a European working group revised the definition of sarcopenia and made muscle strength the most important criterion, ahead of muscle mass. [1] Muscle strength more reliably predicts whether someone will fall or lose their independence.
In 2024, an international panel of experts defined three components: muscle mass, muscle strength, and muscle strength in relation to muscle size. [2] How well someone walks or gets up, on the other hand, is considered a consequence of sarcopenia, not one of its components.
The number of people affected therefore depends heavily on how it is measured. In a study of more than 12,000 participants in China, the proportion ranged from 3 to 32 percent depending on the definition. [5]
According to a 2025 German review, mortality among people with sarcopenia is approximately doubled. They also have to be hospitalized significantly more often. [4]
Sarcopenia is now considered an independent muscle disease with its own diagnostic code. [1] Four simple tests described in the article [[ link: show whether you are affected yourself sarсopenia self-test ]].
Why the body responds less effectively to training with age
A 30-year-old and a 70-year-old do the same training, and both build muscle, but not at the same rate. This is due to anabolic resistance: As we age, muscle cells respond more sluggishly to exercise and protein.
Muscle protein synthesis slows down, anabolic hormones decline, mitochondria work less efficiently, and the connection between nerves and muscles becomes more prone to problems. [3] But the biggest single factor is physical inactivity: fewer than 15 percent of people over 65 are as physically active as recommended. [2]
Because the signal is weaker in old age, it has to be made stronger. Walking is therefore not enough, and each meal needs to contain more protein than it did in younger years.
In first place: Strength training
Strength training has the strongest effect, two to three times per week with increasing resistance. A review of 22 randomized studies confirms gains in muscle strength among people aged 75 and older, including those over 80. [7]
A 1990 study of people between 86 and 96 years old became famous. After eight weeks of training, their leg strength had more than doubled. [6]
You do not need a gym for this. In a Norwegian study, people requiring care, with a median age of 86, trained at home with resistance bands for eight months and became stronger than a comparison group that received advice only. [8]
When sarcopenia is already present, muscle strength and mobility improve first. In 24 studies involving 951 people affected, grip strength, walking speed, and the ability to stand up improved reliably, whereas measured muscle mass did not. [9]
In second place: Protein
Professional societies recommend that healthy older adults consume at least 1.0 to 1.2 grams of protein per kilogram of body weight per day. [10] That is significantly more than the often-cited 0.8 grams that apply to adults in middle age.
The German S3 guideline on clinical nutrition in older age, published in 2025, also devotes a separate chapter to the treatment of sarcopenia. [11]
In third place: Supplements
Creatine has the strongest evidence. In 22 controlled studies with 721 participants between 57 and 70 years old, it produced around 1.4 kilograms more lean mass than the same training without creatine. [12]
The effect is significantly greater with training than without it.
The evidence for omega-3 is weaker. It could make muscle cells more sensitive to protein and resistance exercise again.
Controlled studies in older people are lacking for most of the other substances being promoted.
When weight is lost
Every weight loss also costs muscle. Since weight-loss injections such as semaglutide (Ozempic) and tirzepatide (Mounjaro) have become widespread, greater weight loss has also meant greater loss of muscle mass. [13]
A high amount of body fat combined with low muscle mass is called sarcopenic obesity. It is easily overlooked because body weight may appear normal or even be elevated. [4]
State of the evidence
This table ranks the interventions by the strength of their evidence.
| Area | Level of evidence |
|---|---|
| Strength training, two to three times per week | Strong (meta-analyses) |
| Increase in muscle strength from age 75 onward | Strong (22 RCTs) |
| Muscle strength and mobility in sarcopenia | Strong (24 RCTs, n=951) |
| Muscle mass in existing sarcopenia | Not established (24 RCTs, n=951) |
| Protein from 1.0 grams per kilogram | Strong (professional societies) |
| Creatine in addition to training | Strong (22 RCTs, n=721) |
| Omega-3 in addition to training | Initial indications |
| Supplements without training | Less than with training |
| Protection against falls and fractures through supplementation | Still outstanding |
Every row rated strong includes either training or protein. No one has yet directly studied whether supplements prevent falls and bone fractures.
What does this mean in practice?
Age-related muscle loss can be slowed, and muscle strength and mobility can be regained at any age. The study of 86- to 96-year-olds is the best evidence of this.
This requires two things: two to three strength-training sessions per week with increasing resistance, and 1.0 to 1.2 grams of protein per kilogram of body weight, distributed across three meals. That achieves most of the potential benefit.
Supplements build on what training has established. And the earlier you start, the easier it becomes: at 50, you are working preventively; at 75, you are addressing a deficit.
