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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

What peptides are · Part 1: Building blocks

Side chains give each amino acid a personality

Lesson 1.1.2 · 6 min read · Professional plan

What you'll learn

Side chains differ in size, charge and attraction to water.
One common scheme sorts them into five groups: nonpolar, aromatic, polar uncharged, positive and negative.
Glycine is the smallest, proline stiffens the chain, and cysteine can form disulfide bridges.
Changing one amino acid can change how a protein behaves, as in sickle cell disease.

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