Research notes on the molecules shaping modern biology.

Cognitive Health & Aging

Plasma GHK-Cu declines from roughly 200 ng/mL at age 20 to 80 ng/mL by age 60—a pattern that has prompted researchers to examine peptide biomarkers in aging and whether shifts in circulating humanin and related peptides track longevity signaling pathways.

Updated Aug 19, 2026

Peptide Mechanisms

In 2004, cultured cell studies revealed that GLP-1 receptors desensitize within hours of continuous exposure—a finding that should have foreclosed their use as durable therapeutics, yet animal models and clinical trials told a different story about peptide tachyphylaxis and long-term receptor tolera

Updated Aug 18, 2026

Peptide Mechanisms

In 2019, researchers began systematically measuring circulating peptide blood levels through LC-MS and related assays, revealing how nutritional intake correlates with serum peptide concentrations—a measurement challenge that has only recently moved beyond clinical endocrinology into broader researc

Updated Aug 17, 2026

Peptide Mechanisms

Tirzepatide's approval in 2022 sparked quieter excitement among structural biologists studying peptide biased signaling—how a single receptor activates different cellular pathways depending on which molecule binds to it. The University of Michigan and Eli Lilly teams mapped the mechanism with unusua

Updated Aug 14, 2026

Pharmacokinetics & Absorption

Eli Lilly's 2023 Phase 2 trial data revealed how retatrutide's pharmacokinetics—specifically its absorption and extended half-life enabled by a fatty acid modification—allow weekly dosing despite targeting three hormone receptors simultaneously.

Updated Aug 13, 2026

Glucagon Receptor Signaling

In 1923, Canadian researchers identified glucagon as insulin's metabolic counterpart—a pancreatic hormone that raised blood sugar. A century later, glucagon receptor agonist research reveals the hormone's effects extend far beyond glucose regulation, influencing lipid metabolism, hepatic physiology,

Updated Aug 12, 2026

NASH Fibrosis & Peptide Therapy

In March 2024, the FDA approved resmetirom for NASH, marking the first regulatory victory after two decades of failed Phase 3 trials—yet NASH fibrosis progression and peptide therapy's potential role in reversing scarring remain largely unexplored in clinical settings.

Updated Aug 11, 2026

Synthesis & Manufacturing

A single amino acid substitution transformed a reliable formulation into a cloudy suspension, revealing how peptide solubility aggregation and precipitation remain unpredictable even when protocols stay unchanged. The phenomenon—governed by charge distribution, pH buffering, and hydrophobic clusteri

Updated Aug 10, 2026