Lets make it clear: peptides are not drugs (yet), they are research compounds
As research compounds there are no regulations or certifications to comply to and no producer or seller has obligation to market research compounds respecting determinate standard levels.
Since there are no obligations is surrealistic to aspect certain standards which will cost more, especially in such a small niche market.
That said there are companies caring more about quality and other caring less, there are companies performing independent tests on the batches they receive and companies that don't and rely solely on the certificate of analysis provided by the producers.
We all know Ceretropic holds a good reputation that probably it deserves and certainly try to market products respecting at least a certain standard but once the final user gets a positive effects is that really enough to state that the products are pharmaceutical grade?
I don't think a user is able to understand if the product is pure or not, it may be able to tell if gets an effect from it but to asses purity is a very different story.
Until a compound is not a drug (and at that point almost all peptides will need a prescription) nobody can be sure of the purity of it if an independent analysis is not performed (and still that may vary from batch to batch).
Ceretropic as other companies market peptides because there is a demand for compounds that are not ready available since are only for research, they try to satisfy that demand at the best they can (and make their business in the process) but it is a very gray area where nobody really knows where the boundaries of legality are, we can't expect those companies to invest to produce their own peptides under strict quality standards since things may change overnight (did you noticed Ceretropic doesn't carry anymore peptides they where carrying til few months ago? Wondering why? Try to guess...).