It is dose dependent. Epicatechins have benefits, but at high doses as the ones contained in supplements of this kind have more cons than pros. Unless you don't care to possibly get cancer for just a couple of extra pounds of muscles.
Can you provide the evidence that supplemental epicatethins can cause cancer? Or the dose response relationship between follistatin and cancer? The duration in which follistatin must be increased and the percentage in which it must be increased, whether there are faulty feedback mechanisms contributing to the effect, how the follistatin was induced (injection or was it just a measure of levels) and whether you can correlate epicatethin to cancer (a natural increased versus one by faulty machinery)
I'll liken this argument to another I repeatedly hear - We at SNS sell supplemental Arachidonic Acid which has evidence showing it can lead to systemic inflammation in the body - this evidence is a primary reason why people will not take it (who are informed on such matters), however what the argument fails to consider is the population in which Arachidonic Acid is more harmful than beneficial. Arachidonic acid supplementation is ONLY harmful when lipid perioxidsation products are also mixed - which are not included In supplemental capsules.
Studies done for up to 50 days (our recommended safety limit) show supplemental ARA at <2g HAS ZERO effect on pro-inflammatory markers and several showing reduction in IL-6 (which means a REDUCTION in pro inflammation).
And further A meta-analysis by Cambridge University looking for associations between heart disease risk and individual fatty acids reported a significantly reduced risk of heart disease with supplemental ARA and EPA DHA.
But yet we are repeatedly told to limit it. Why? Because the typical American diet is so pro-inflammatory that people correlate ARA (given its nature) to the effects rather than their diet as a whole. Limiting processed foods and other things can reduce perioxidation of lipids.
In short, finding a study that shows and effect MUST be related to the population we are a part of (using supplemental epi for example). In soft sciences, you can not just find an end product of something and then attribute it to EVERYTHING that raises that variable.