Skip to content

Educational reference only. Not medical advice. Nothing on this site is for sale.

October 28, 2026CompoundingHHS lets 503A pharmacies compound six peptides under an interim enforcement discretion policyOctober 28, 2026Trial resultRetatrutide beats Ozempic on blood sugar and weight in head-to-head TRANSCEND-T2D-2 trialOctober 23, 2026FDA approvalFDA extends once-weekly insulin icodec (Awiqli) to children 10 and older with type 2 diabetesOctober 21, 2026CompoundingCitizen petition asks FDA not to allow compounding of seven peptides reviewed by its advisory committeeOctober 1, 2026Trial resultSurvodutide SYNCHRONIZE-2 phase 3 results in obesity with type 2 diabetes published in NEJMSeptember 30, 2026Trial resultEloraTZP (eloralintide plus tirzepatide) phase 2 results presented at EASD 2026September 30, 2026Trial resultOrforglipron ACHIEVE-4 cardiovascular safety trial published in The LancetSeptember 29, 2026Trial resultFull TRIUMPH-2 retatrutide results published in The LancetSeptember 24, 2026FDA approvalFDA approves insulin efsitora alfa (Onswik), a once-weekly basal insulin for type 2 diabetesSeptember 21, 2026WADAWADA publishes 2027 Prohibited List, naming peptides as examples of non-approved substances

October 28, 2026CompoundingHHS lets 503A pharmacies compound six peptides under an interim enforcement discretion policyOctober 28, 2026Trial resultRetatrutide beats Ozempic on blood sugar and weight in head-to-head TRANSCEND-T2D-2 trialOctober 23, 2026FDA approvalFDA extends once-weekly insulin icodec (Awiqli) to children 10 and older with type 2 diabetesOctober 21, 2026CompoundingCitizen petition asks FDA not to allow compounding of seven peptides reviewed by its advisory committeeOctober 1, 2026Trial resultSurvodutide SYNCHRONIZE-2 phase 3 results in obesity with type 2 diabetes published in NEJMSeptember 30, 2026Trial resultEloraTZP (eloralintide plus tirzepatide) phase 2 results presented at EASD 2026September 30, 2026Trial resultOrforglipron ACHIEVE-4 cardiovascular safety trial published in The LancetSeptember 29, 2026Trial resultFull TRIUMPH-2 retatrutide results published in The LancetSeptember 24, 2026FDA approvalFDA approves insulin efsitora alfa (Onswik), a once-weekly basal insulin for type 2 diabetesSeptember 21, 2026WADAWADA publishes 2027 Prohibited List, naming peptides as examples of non-approved substances

Peptide CompendiumLanguageSign in

Frontiers · Part 3: Cell-penetrating and stapled peptides

Getting through the wall

Lesson 10.3.1 · 6 min read · Advanced plan

What you'll learn

The cell membrane is a strong barrier, and most peptides cross it poorly.
Cell-penetrating peptides, first found in 1988 in the HIV protein TAT, can enter cells and carry cargo.
They get in by passing straight through or by being swallowed into endosomes, and escaping endosomes is a major hurdle.
As of the 2020 review, no CPP drug had FDA approval.

← Find it, then treat it, and a cautionary tale · All lessons in Frontiers · Stapled peptides →