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The Study

Three Weeks of Creatine Monohydrate Supplementation Affects Dihydrotestosterone to Testosterone Ratio in College-Aged Rugby Players

In simple terms

This study showed that when rugby players took creatine, their bodies made more of one hormone (DHT) compared to another (testosterone). But it doesn't prove creatine causes this in everyone — just in these 20 guys. It's like seeing your friend get taller after drinking milk — it might be connected, but we can't say milk makes everyone taller.

53%

Analysis score

53/ 90

Maximum 90 for a randomized controlled trial.

Where the score came from

Reporting0
Methodology77
Publication100
Statistical23
Study type (basis of the score)
Randomized Controlled Trial
Level 1b - Individual RCT
What’s the bottom line?

This study looked at whether taking creatine supplements changes the levels of two male hormones: testosterone and DHT.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Randomized Trials
Level 1b
53

53 / 100

Quality score

Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.

Can establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1Even though DHT increased, muscle size and body fat didn't change in just 3 weeks — so the hormone shift didn't quickly affect appearance or strength.
  2. 2After taking creatine, DHT went up by 56% at first, then stayed 40% higher; testosterone didn't change; the DHT-to-testosterone ratio stayed 22% higher for 14 days after the first week.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Clinical Journal of Sport Medicine

Year

2009

Authors

J. van der Merwe, N. Brooks, K. Myburgh

23 citations
Analysis v5

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