GDF-11 biomarkers: believable?

Note this is not meant to impugn the work Steve is doing, or to cast doubt on his sincerity or honesty. Also this post examines the biomarker results, not the proposed value of GDF-11 usage. 

I'm wondering however, are the miracle results really possible? I also do the same daily waking biomarkers, and more even that they measure (not the more expensive clinical machines however Steve & Co have purchased), and have been measuring during all these treatments I'm doing. The difference is that I have not seen this reflected in the biomarkers. 

For example take blood pressure. I easily see the effects of stress, diet and most importantly sleep. NAD has a peripheral affect of improving sleep which has follow through to BP, but it's a somewhat soft correlation. Making sure I don't eat too much the night before, and having a good day has more impact. Otherwise I'm not seeing a trend from the varied approaches. 

Stepping back, GDF-11 plays into stem cell function, yet the treatments I've done are mitochondrial. Which is more fundamental to daily function? It seems to me that mitochondria are as they directly affect, among other things, energy level, which plays into everything. 

Playing the other side, they are seeing this  across multiple people - OK fine, but it wouldn't be the first time that correlation isn't causation, if it's not causal. There's a lot of noise in these measurements so that could be playing into this (small population size of a noisy measurement), or it could be due to issues with the participants measurement technique. The aspiration tests and BP are quite noisy, and yes Steve does an averaging trend AFAIK, but a researcher does more sophisticated statistics than that. 

 Personally I would love this to be true, but am having a hard time seeing it.