Ray Peat often talked about how prolactin is a stress hormone and should be suppressed to a minimum required baseline. The most common ways to reduce prolactin are vitamin E and P5P or a dopamine agonist like lisuride or cabergoline. For the dopamine agonists, they work with prolactin in a feedback loop where high dopamine suppresses prolactin, while high prolactin suppresses dopamine. However, the dopamine agonists, while super effective, have problems. Lisuride is expensive and only easily available from Idealabs and doesn't last very long. Meanwhile, cheaper and longer lived agonists like cabergoline run with a nonzero risk of heart fibrosis, unless you use a low dose. So, I was interested in a more robust way to suppress prolactin aside from the commonly known options that could both be effective and last a while, and I might have found something.
The Del1-9-G129R-hPRL peptide is a variant of the human prolactin hormone specially crafted to antagonize prolactin receptors. Peptides in general have really caught on because they can have interesting properties that normal small molecules can't easily achieve. In addition, they might be easier to manufacture. Anyway, Del1-9-G129R-hPRL is one example of modification of an existing peptide with changed receptor activation. Antagonism of prolactin receptors should achieve all the things Peat aimed for when suppressing prolactin the normal way as well as increase dopamine due to the feedback loop.
There are a few studies on Del1-9-G129R-hPRL:
Structural and Thermodynamic Bases for the Design of Pure Prolactin Receptor Antagonists
Prolactin receptor antagonism uncouples lipids from atherosclerosis susceptibility
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C10&q=Del1-9-G129R-hPRL&btnG=
You can even buy it!
https://plr-ltd.com/products/detail/179
However, Del1-9-G129R-hPRL, like many peptides has a catch. As it is merely prolactin with a couple slight modifications, it retains prolactin's short half life of around 40 minutes. This is unacceptable if you were to use it as a Peaty supplement, unless you'd want to inject yourself with a needle every hour or so. So, in light of this, there is a variant of Del1-9-G129R-hPRL: PrlRA-ABD. PrlRA-ABD has a much longer half life on the order of 24 hours or more, so it would be practical to use for prolactin suppression.
PrlRA-ABD also has studies backing it up:
https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.1112987/full
https://www.proquest.com/openview/1ea422e2efb6c414ca81c014237bdc7f/1?pq-origsite=gscholar&cbl=2026366&diss=y
https://www.proquest.com/openview/387728698a91276b1e8522549fd4ca0b/1?pq-origsite=gscholar&cbl=2026366&diss=y
But these are all the studies that exist. So, what we need to do now is figure out how to make PrlRA-ABD so that we can do research with it. I am interested in hearing if there is anything else comparable to these peptides that is actually commercially available right now so that we can have a better way to suppress prolactin.
