Let me answer this question: First of all, Z-Stack comes without Vitamin K2, which, in the long term, could lead to the calcification of arteries. Also, the zinc content is much too high, which could also lead to adverse effects over time. Last but not least, the product does not contain magnesium, which is essential for vitamin D synthesis, and instead has high levels of quercetin, which in the long term could damage your intestinal mucosa. Everyone who has studied medicine should be aware of these metabolic effects. But it seems that Zelenko eventually wasn’t really in charge, but the CEO of The Wellness Company, Foster Coulson, was—which is no excuse for that bad product though.

On the other hand, their flawed product and their unwillingness to change the product's composition motivated me to found @sunfluencer. If they had listened to my advice instead of attacking me, I would never have started my journey to turn my words into actions and to design a product that I'm willing to put into my body every single day.

Cheers,
Simon @Goddek