The Claim

Nine weeks of high-load or low-load resistance training in recreationally trained males has no significant effect on basal or acute post-exercise salivary testosterone or cortisol levels.

Source: Muscle Hypertrophy, Strength, and Salivary Hormone Changes Following 9 Weeks of High- or Low-Load Resistance Training

What the research says

Supports is higher

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

Supports
62score
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.

Description
1 study reviewed
In plain English

Nine weeks of either heavy or light weight training does not change resting or exercise-related levels of testosterone or cortisol in the saliva of men who train recreationally.

See the scientific wording

Neither high-load nor low-load resistance training significantly alters basal or acute post-exercise salivary testosterone or cortisol levels in recreationally trained males over nine weeks, suggesting systemic hormonal changes are not a primary driver of hypertrophy or strength adaptations.

Why this might work

When muscles are worked hard, whether with heavy or light weights, the physical stretch and burn inside the muscle trigger local signals that build more muscle tissue. These signals do not rely on changes in hormone levels in the blood or saliva. The body adjusts how much hormone binds to muscle cells instead of releasing more, so hormone levels stay flat even as muscles grow.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Muscle Hypertrophy, Strength, and Salivary Hormone Changes Following 9 Weeks of High- or Low-Load Resistance Training

    This study found that whether men lifted heavy or light weights for nine weeks, their stress and sex hormone levels in saliva didn’t change — meaning those hormones aren’t the main reason muscles grow or get stronger.

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.