The Claim

In sedentary adults undergoing resistance exercise, daily whey protein supplementation at 1.5 g/kg body weight for four weeks is associated with a significant increase in circulating insulin-like growth factor 1 (IGF-1) levels (p < 0.05), while resistance exercise alone does not produce a significant change in IGF-1 levels.

Source: Correlation between physiological and biochemical variables during short term adequate protein intake combined with resistance exercise in sedentary adults

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
75score
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.

Correlation
1 study reviewed
In plain English

In sedentary adults who perform resistance exercise, taking 1.5 grams of whey protein per kilogram of body weight daily for four weeks results in higher levels of insulin-like growth factor 1 in the blood compared to performing resistance exercise without whey protein.

See the scientific wording

In sedentary adults undergoing resistance exercise, daily whey protein supplementation at 1.5 g/kg body weight for four weeks is associated with a significant increase in circulating insulin-like growth factor 1 (IGF-1) levels (p < 0.05), while no such change occurs with resistance exercise alone, suggesting a potential role for IGF-1 in mediating muscle adaptation under this specific intervention.

Why this might work

When a person drinks whey protein and lifts weights, the amino acids from the protein trigger the liver to release more IGF-1 into the blood. This IGF-1 binds to muscle cells and turns on a chain of signals that build new muscle proteins and stop the breakdown of existing ones. At the same time, the combination of exercise and protein reduces a natural blocker of muscle growth, allowing more muscle to form.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Correlation between physiological and biochemical variables during short term adequate protein intake combined with resistance exercise in sedentary adults

    When sedentary people lift weights and drink whey protein every day for four weeks, their body makes more IGF-1, a protein that helps muscles grow. But if they just lift weights without the protein, their IGF-1 levels don’t go up.

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.