Back in the day before the fentanyl craze, REAL China white was usually the purest heroin out there. Pharmaceutical grade heroin is off white, sometimes looking more white than off-… but those days are long over. Rarely can you find true China white that is the color it should be that truly doesn’t have fent or other synthetic substances in it (which are usually just other analogues of fent). Sure, this new synthetic stuff is strong, but it lasts about an hour, maybe two if you’re lucky. Not to mention it commonly has hit spots and is just even more dangerous in general with fent, fent analogues, and the new etazene stuff. It has zero legs whatsoever compared to real H, which now is almost always tan, light brown, or grey. Usually I had always found that the greyish stuff with the strong scent of vinegar is the best.
Recently a batch of tannish-grey, non-synthetic from a particular source was EC tested at 89% pure H with no traces of fent whatsoever, which is fantastic if you ask me. A second source wasn't far behind at 86%. Even though the white synthetic is stronger, usually you get more bang for your buck with the real deal H because it was often cheaper in my experience and lasted 2-3 times as long at least. Personally I liked the feel of it much better when I did it in the past anyway. I just don’t get the hype or appeal at all around this white, synthetic fenta-dope. But to each his own I suppose.
Edit: it should also be noted that fentanyl test strips are notoriously inaccurate, particularly when testing for fentanyl analogues, rep finally carfentanil. Test your product multiple times, and mix it up well after you receive it to ensure you are working to eliminate hotspots and increasing the likelihood of your test being accurate, because counting on a fentanyl dealer to mix it up effectively so that you’re safe is probably not the smartest idea
