Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience both.
So the question, as narrowly as I can put it: which effects tachyphylax and which persist, because the answer explains why tolerability improves while the appetite effect keeps working.
Not looking for reassurance. Looking for the part I have got wrong.
mike_mod said:Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience…
Semaglutide structural biology relevant to the pharmacology: semaglutide is a 31-amino acid peptide with 94% homology to native GLP-1(7-36). Three key modifications enable its pharmacokinetic profile:
- Aib8 substitution: DPP-4 resistance (prevents enzymatic degradation)
- Arg34 substitution: improved chemical stability
- C18 fatty diacid at Lys26: albumin binding → long half-life
These three modifications transform a peptide with a 2-minute half-life (native GLP-1) into one with a 168-hour half-life (semaglutide). A masterclass in peptide engineering.
LipidDoc_ATL said:Semaglutide structural biology relevant to the pharmacology: semaglutide is a 31-amino acid peptide with 94% homology to native GLP-1(7-36).
Agreeing with LipidDoc_ATL, and the qualification matters more than the agreement. 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.
If somebody has the primary source to hand I would rather cite it than paraphrase it.
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Browse GL Biochemmike_mod said:Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience…
Can confirm. Same sequence, different timescale.
Adding the clinical framing, because it changes how the question reads.
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.
[1] Novo Nordisk investor presentation, September 2023.