Testing Your Supplements

That's good. Having a reference standard makes it much easier. Then you have a lot more options for ID, and an accurate purity assay is a possibility. You could use HPLC for both ID and assay if you want. I'd personally do more techniques to confirm. However, if the retention time matches, it is likely the same compound. IR is super nice for an extra confirmation. If you have an IR spectra that matches the reference standard, and the HPLC retention time matches, you don't really need to go crazy with an NMR. That's if it is pure, though. If there are some impurities in it that have different functional groups, the IR is going to show them (as long as they contain carbon). Sometimes certain impurities can mask weaker signals in the primary compound. Again, remember that HPLC is only going to show impurities that have a chromophore, and if you are using an HPLC without a PDA detector you are only going to be seeing one wavelength. That's a trick a lot of Chinese companies use. Let's say you run your non-PDA detector HPLC at 220nm and see an impurity. They will tell you to run it at 190nm or 250nm. Then maybe the impurity peak goes away, and they say: "See, it's pure!" When you just fiddled with the detector to mask it. However, if you have a reference standard, you can just run the same methods on each and do math to get the assay. Then I would do melting point, too, as it is so easy and a hard number you can't mask.

As for suppliers, it's a crap shoot. It's especially bad right now because of some political things going on in China. A few large labs used their government contacts to shut down other labs under the guise of "environmental regulations." This allowed these labs to gain a monopoly on a few key precursors to certain compounds. For instance, there is only one lab making MK-677 and Ostarine now, as they gained a monopoly over some key precursors. The quality has tanked for those two. Seriously, it has gone down the shitter. I would not consume any MK-677 or Ostarine coming from China at the moment. Until someone comes up with a new synthesis route that doesn't need those precursors, or somebody gets around them with their own political contacts, we are left with this single lab putting out garbage product. It sucks!