The Claim

Untrained individuals can expect to gain approximately 1.5 kg of fat-free mass over 8–12 weeks of resistance training, with gains plateauing significantly after the first 6 months, and long-term annual gains typically ranging from 0.5 to 2.5 kg depending on training experience and genetics.

Source: Load-induced human skeletal muscle hypertrophy: Mechanisms, myths, and misconceptions

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
1score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

If you're new to weight training, you can expect to build about 1.5 kg of muscle in the first couple of months, but after six months, the gains slow down a lot—after that, you might only add half to two and a half kilos of muscle per year, depending on your body and how long you've been training.

See the scientific wording

Untrained individuals can expect to gain approximately 1.5 kg of fat-free mass over 8–12 weeks of resistance training, with gains plateauing significantly after the first 6 months, and long-term annual gains typically ranging from 0.5 to 2.5 kg depending on training experience and genetics.

What the research says

1 study
  1. Study: Load-induced human skeletal muscle hypertrophy: Mechanisms, myths, and misconceptions

    This study looks at how lifting weights makes muscles grow and says the gains people see are real but limited — which matches what the claim says about how much muscle you can build over time.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.