I bought mine from edited out because I realize this wasn’t a pm lol, they test every batch they sell through janoshik (probably the most respected peptide tester) and include the results. They also reimburse members of the community who send their own vials for testing as a way to show that they don’t bullshit the results. You can take a look at their telegram channel. In terms of US vendors this is who I would suggest, you just have to wait for them to do presales for the GLPs for the good prices.

Otherwise there’s stairwaytogrey which is where you’ll find all the Chinese vendors (join the telegram). That’s more Wild West and you have to go out of your way if you wanna get stuff tested as a group or try to find out if a batch you bought from a vendor was already tested by a group. But it’s dirt cheap.

Did you buy from China? Or from a middleman that had the batch tested? Honestly if it was tested I’d really not worry about it (and even if it wasn’t I personally feel that stuff like tirzepatide tests as clean so often in the grey space that subcutanous injections done properly really don’t represent that much risk).

https://particlepeptides.com/en/content/48-peptide-calculator

With the GLPs I’d say start with half the recommended starting dose for your first week to assess if you’re a super responder. Splitting the dose into bi weekly can also help smooth out the intensity if the side effects are too much. I personally ended up using a smart scale and only increased my dose when I was plateauing, which helped keep the effects mild (also lower doses meant spending even less).

Make sure to reconstitute with Hospira bacteriostatic water, the other stuff is such a crapshoot and not worth the risk. Watch videos on how to do injections/recon/etc.