Stanfield's logic is simply wrong.

1. Spermidine found to increase lifespan and fertility in mice.

2. Spermidine levels not found to increase in blood or certain tissues when fed to mice.

3. Therefore, 1 is wrong.

Finding 2 in no way disproves 1. Facts which could be consistent with both 1 and 2 being true:

- spermidine metabolites are responsible for benefits

- while spermidine levels are maintained, excess spermidine is used beneficially

- experimenters in 2 simply haven't looked in the right tissues

And so on. TFA says there were observed phenotypic improvements (follicular health, oocyte number and quality), which categorically trump 2's failure to observe increase in spermidine levels. And none of this says anything directly about spermidine's effects in humans

I’ve watched a lot of Stanfield’s videos. Over time I came to realize that his whole image is built on being “the critic” and tempering optimism around these treatments. Except for his own personal research, which he’d like you to help fund :)

At the end of the day, “the critic” is a valuable job. Someone has to do it. Not sure it is really helping progress the industry though. I think it would be better for him to leave this to the lawyers tho.