Taking these supplements didn’t change the level of testosterone in men with slow-growing prostate cancer, which is good news because testosterone can sometimes fuel prostate cancer.
Scientific Claim
A phytochemical-rich supplement with or without probiotics does not alter testosterone levels in men with indolent prostate cancer over a 16-week period.
Original Statement
“There was no difference in testosterone levels.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The claim is a direct, null finding reported without inference. The RCT design with objective lab measurement supports a definitive conclusion of no effect.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aWhether this supplement class consistently has no effect on testosterone across diverse populations and formulations.
Whether this supplement class consistently has no effect on testosterone across diverse populations and formulations.
What This Would Prove
Whether this supplement class consistently has no effect on testosterone across diverse populations and formulations.
Ideal Study Design
A meta-analysis of at least 6 RCTs measuring serum testosterone before and after supplementation with phytochemicals (with or without probiotics) in men with indolent PCa, using standardized assays and timing.
Limitation: Cannot detect very small effects or long-term hormonal adaptation.
Randomized Controlled TrialLevel 1bIn EvidenceCausal evidence that the supplement does not alter testosterone in this population.
Causal evidence that the supplement does not alter testosterone in this population.
What This Would Prove
Causal evidence that the supplement does not alter testosterone in this population.
Ideal Study Design
A double-blind RCT of 200 men aged 65–80 with indolent PCa, randomized to supplement or placebo, measuring serum testosterone at baseline, 8, and 16 weeks using LC-MS/MS assay.
Limitation: Short duration may miss delayed hormonal effects.
Prospective Cohort StudyLevel 2bReal-world consistency of testosterone stability with long-term supplement use.
Real-world consistency of testosterone stability with long-term supplement use.
What This Would Prove
Real-world consistency of testosterone stability with long-term supplement use.
Ideal Study Design
A prospective cohort of 400 men with indolent PCa tracking serum testosterone every 6 months for 3 years while using the supplement, adjusting for age, BMI, and comorbidities.
Limitation: Cannot control for concurrent medications or lifestyle changes.
Evidence from Studies
Supporting (1)
This study gave men a special supplement with plant chemicals and sometimes probiotics for 16 weeks and checked their testosterone levels before and after — and found no change. So the supplement didn’t affect testosterone, just like the claim says.