Harmful isn't that likely IMO. I'm sure its not dosed at 400 tho. I've tried to get short esters to hold over 100 and long to hold over 200/250. Fof this you need eo, unless youre just that good. They're claiming there's 100mg of short AND 300mg of long with only 20%bb?! Maybe, but I doubt it. The two long esters are odd too. Why cyp And enan? They're pretty much the same. At least in dust, you have 30mg prop (short) 60mg Iso, 60mg phenylprop (medium esters) and test DECA (med/long ester) so it'll release evenly thru the week was the idea. Putting prop and enan/cyp in a blend, it'll release the prop within days, and the longs two weeks later? Why? I dunno, bottom line, its probably not harmful per se, I'd look for others that have used it. "Hi test labs" too? Screams amateur ugl, someone discovered powders. See of your friend knows who it comes from. Its really all based on the intentions/skill of the cook