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ForumsOther Peptides & Research CompoundsSelank and Semax — anxiolytic peptides overview

Selank and Semax — anxiolytic peptides overview

NeuroNate Sun, Jun 7, 2026 at 9:13 PM 2 replies 73 viewsPage 1 of 1
NeuroNate
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Jun 7, 2026 at 9:13 PM#1

Writing this once so I can stop repeating it across threads. It is about the pharmacology, and it is deliberately narrow — everything I am not confident about is marked as such.

What is actually established

The pharmacokinetics explain nearly every practical question asked here. Albumin binding above 99% slows clearance enough to make weekly dosing possible; a terminal half-life near a week means four to five weeks to steady state and therefore a four-week titration interval; subcutaneous bioavailability around 89% means injection site barely matters. Those three facts answer most timing questions before they are asked.

The condition it depends on

The adaptation point cuts both ways: tachyphylaxis to gastric emptying is why tolerability improves, and it is also why people who were relying on physical fullness feel the effect fade while the appetite effect is still working.

The practical version

Numbers worth memorising for this class: Tmax one to three days for the weekly peptides, terminal half-life about a week for semaglutide and about five days for tirzepatide, steady state at four to five half-lives, subcutaneous bioavailability high enough that site choice is irrelevant.

What I am not sure about

What I am after is which effects tachyphylax and which persist, because the answer explains why tolerability improves while the appetite effect keeps working. I have searched first, so if this is covered somewhere point me at it and I will read it.

— NeuroNate · corrections welcome and will be edited into this post with credit
40 10jason_paloalto, Dr.LeslieOBGYN, MikeNYC_runner and 37 others
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Dr.KarenChen
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Jun 7, 2026 at 9:26 PM#2
NeuroNate said:
The pharmacokinetics explain nearly every practical question asked here.

Amycretin (AMY/GLP-1 dual agonist) emerging data relevant to the pharmacology: Phase 1 showed -13.1% body weight at only 12 weeks, the fastest trajectory ever seen for an anti-obesity agent[1].

Amylin receptor agonism enhances satiety signaling through the area postrema and reduces glucagon secretion. Combined with GLP-1R agonism, this dual mechanism may produce even greater efficacy than current agents.

Early-stage data — interpret with caution. But the trajectory is extraordinary.

References:
[1] Novo Nordisk investor presentation, September 2023.
39 9JessicaM_2024, TomFromTexas, mike.trainer_LA and 36 others
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InsuranceTom
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Jun 7, 2026 at 9:39 PM#3
NeuroNate said:
The pharmacokinetics explain nearly every practical question asked here.

This is where I part company with the consensus forming above. The mechanism is more central than most summaries suggest. Receptor agonism in the arcuate nucleus activates POMC neurons and inhibits AgRP/NPY signalling, and the downstream MC4R pathway is the same one disrupted in monogenic obesity — convergent genetic evidence that the target is the right one. Peripherally there is glucose-dependent insulin secretion, glucagon suppression and delayed gastric emptying, but the gastric component largely adapts over months while the central effect persists, which is why the durable effect is appetite rather than fullness.

Last edited: Jun 8, 2026 at 2:39 AM
38 8Dr.ReproEndo, lucas_SP_BR, lisa_labSD and 35 others
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Dr.BariatricHTX
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Jun 7, 2026 at 9:52 PM#4
InsuranceTom said:
The mechanism is more central than most summaries suggest.

Receptor pharmacology relevant to the pharmacology: semaglutide is a GLP-1R agonist with a C-18 fatty acid chain that enables albumin binding (>99%), creating a depot effect with a ~168-hour half-life enabling weekly dosing[1].

Tirzepatide is a dual GIP/GLP-1R agonist with higher GIP affinity (5:1 GIP:GLP-1 potency ratio). The GIP component may enhance beta-cell function and adipocyte lipid metabolism beyond what GLP-1 alone achieves.

For the pharmacology, the pharmacology explains the clinical differences between these agents.

References:
[1] Lau J, et al. J Med Chem. 2015;58(18):7370-7380.
37 7stefan_berlin, Dr.EM_Chicago, pete_RVA and 34 others
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ben_calgary
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Jun 7, 2026 at 10:59 PM#5
Dr.KarenChen said:
Amycretin (AMY/GLP-1 dual agonist) emerging data relevant to the pharmacology: Phase 1 showed -13.1% body weight at only 12 weeks, the fastest…

Mine went the same way, slower.

36 6NauseaFreeNow, SteveThurs, B12Beth and 33 others
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