The tag is what makes you sick.
Untagged is what you want.
It’s extremely difficult to properly remove the tag.
The peptide company I used to rep for had ACE-083 synthesized in the USA, and they had to scrap 3 batches because the process of removing the tag was so difficult to do correctly. It took 4 or 5 months to get the end product.
You’ll know if it has the tag because you’ll get flu-like symptoms and swelling and soreness at the injection site.