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 rarely exceeding 3 kg in the first year without pharmacological aid.

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, your gains slow down a lot—and you probably won't gain more than 3 kg of muscle in a year unless you're using drugs.

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 rarely exceeding 3 kg in the first year without pharmacological aid.

What the research says

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

    This study looks at how muscles grow from weight training and says natural gains are limited — you can’t get super big without drugs, which matches the claim that people usually gain less than 3 kg of muscle in a year.

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.