centertrt.org › Best-Testosterone-BoostersBest Testosterone Boosters | What's Legit And What Isn't! - Libido - Customer Satisfaction - Ingredient Quality - Potential Side Effects - Value We also don't approve of proprietary blends, these mean we don't really know if you you're getting good value. Especially considering only around 30% of testosterone supplements actually have been shown to work, with 70% having no or indeterminant effects. [1]