GIP

Where it comes from

Made in

K cells of the duodenum and jejunum

Sent out by

Fat and glucose arriving in the upper small intestine

Acts on

• Pancreatic beta cells
• Fat tissue
• Bone
• Brain

What it does

• Boosts insulin release while glucose is high ¹
• Promotes fat storage after a meal
• Reduces bone breakdown after eating
• Its insulin effect is lost in type 2 diabetes and returns when glucose is brought down ¹

In medicine

• Tirzepatide acts on the GIP and the GLP-1 receptor together; approved for type 2 diabetes (2022), obesity (2023) and sleep apnoea (2024) ²
• In 469 people with obesity and moderate to severe sleep apnoea, it cut apnoea events by about two-thirds more than placebo at a year ³
• GIP alone is no medicine: its insulin effect is too weak in diabetes to be useful ¹

Beyond the body’s own use

• Both GIP agonists and GIP blockers cause weight loss in trials, which is the field’s standing puzzle ¹
• Maridebart cafraglutide, a GIP-blocking antibody carrying a GLP-1 peptide, took off 12.3% to 16.2% of body weight against 2.5% on placebo at a year in a 465-person phase 2 trial, dosed monthly; larger trials are running ⁴
• Whether the GIP part is why tirzepatide causes less nausea than GLP-1 alone is a hypothesis, not a finding: no trial in people has separated the two receptors