🍪 CompoundTalk uses cookies to improve your experience, analyze traffic, and personalize content. By continuing to use this site, you agree to our Cookie Policy.
Evidence-based GLP-1 & peptide discussion since 2023
ForumsOral GLP-1 AgonistsOral vs injectable GLP-1: bioavailability and efficacy comparison — need advice

Oral vs injectable GLP-1: bioavailability and efficacy comparison — need advice

mike_mealprep Wed, Mar 26, 2025 at 3:34 PM 12 replies 1,712 viewsPage 1 of 3
This thread is more than 14 months old. Information may be outdated. Consider searching for more recent discussions.
mike_mealprep
Member
412
1,890
Jul 2024
Chicago, IL
Mar 26, 2025 at 3:34 PM#1

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.

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.

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.

I would rather have one careful answer than five confident ones.

46 16mia_MS2, LeilaHI, marcus_mpls and 43 others
Reply Quote Save Share Report
SarahChen_PharmD
VIP Member
4,567
22,341
Dec 2023
San Diego, CA
Mar 26, 2025 at 5:20 PM#2
mike_mealprep 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…

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.
45 15NurseKim_ATL, paul_denver, TinaHashiRN and 42 others
Reply Quote Save Share Report
mike_mod
Moderator
7,234
19,823
Nov 2023
New York
Online
Mar 26, 2025 at 7:06 PM#3
SarahChen_PharmD 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…

Agreeing with SarahChen_PharmD, and the qualification matters more than the agreement. 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.

44 14DoseLogDan, SleepFixSam, PurityPaulOR and 41 others
Reply Quote Save Share Report

Sigma-Aldrich — Research-Grade Standards

Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.

Shop Reference Standards
greg_boulder
Member
345
1,567
Jul 2024
Boulder, CO
Mar 26, 2025 at 8:52 PM#4
mike_mealprep 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.

43 13patPC_UT, Dr.DermMIA, fiona_VT and 40 others
Reply Quote Save Share Report
NurseAsh_DET
Member
356
1,567
Sep 2024
Detroit, MI
Mar 27, 2025 at 7:17 AM#5

From the other side of the consultation, briefly.

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:

  1. Aib8 substitution: DPP-4 resistance (prevents enzymatic degradation)
  2. Arg34 substitution: improved chemical stability
  3. 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.

42 12emily_PDX, Dr.SleepRoch, laura_annarbor and 39 others
Reply Quote Save Share Report

Similar Threads

Orforglipron Phase 3 ATTAIN-1 topline — oral non-peptide GLP-116 replies
Oral semaglutide 50mg (Rybelsus HD) — OASIS program results12 replies
Danuglipron BID dosing — Pfizer oral GLP-1 update7 replies
Oral vs injectable GLP-1: bioavailability and efficacy comparison5 replies
Orforglipron food interaction profile — no fasting requirement15 replies
ForumsNewTrendingMembersAccount

Log In

Forgot password?
No account? Register