Preptin
Preptin is a small hormone made by the pancreas and released together with insulin that helps build bone and influences glucose handling; levels are raised in obesity and insulin resistance.
Plain English
Patient-Friendly Explanation
Preptin is a short peptide of 34 amino acids, produced by the same pancreatic cells that make insulin and released into the blood alongside it when you eat, especially when the meal contains carbohydrate. Researchers have identified two jobs so far. First, it is anabolic for bone: it encourages the bone-building cells to multiply and lay down new bone. Second, it amplifies insulin release from the pancreas, so it feeds back into glucose control. Levels are higher in people with obesity, type 2 diabetes and polycystic ovary syndrome, and they tend to track with insulin resistance and body mass index. After substantial weight loss - including after bariatric surgery - preptin falls, along with insulin. Preptin is a research hormone rather than a test ordered in routine practice, but it is interesting because it links three things usually treated as separate: blood sugar, appetite hormones and bone strength.
Medical
Clinical Definition
Preptin is a 34-amino-acid amidated peptide derived from the E-domain of pro-insulin-like growth factor II, co-secreted with insulin from pancreatic beta cells in response to glucose, and first characterised as an osteogenic factor that stimulates osteoblast proliferation, differentiation and bone nodule formation in vitro and increases bone density in vivo. It also acts as a self-amplifying insulin secretagogue, potentiating glucose-stimulated insulin release. In humans, circulating preptin is elevated in obesity, type 2 diabetes, gestational diabetes, polycystic ovary syndrome and in postmenopausal women, and correlates positively with body mass index, fasting insulin, HOMA-IR, HbA1c and bone turnover markers, suggesting it participates in the coupling between energy metabolism and bone remodelling. Preptin decreases after diet-induced weight loss and after bariatric surgery in parallel with improved insulin sensitivity, and rises again with weight regain in some series. It has also been studied for putative roles in beta-cell survival and in vascular calcification, but these remain experimental. Measurement is by immunoassay in research settings only. The clinical interest is mechanistic: preptin is one of several signals - with insulin, amylin, IGF-1 and osteocalcin - that tie pancreatic endocrine function to bone metabolism, and it helps explain why rapid weight loss, particularly after bariatric surgery, is associated with measurable bone loss even as insulin resistance improves. That combination underpins the standard advice to protect muscle and bone during large weight loss with adequate protein, calcium and vitamin D, resistance training and monitoring of bone density.
Key Insight
Why It Matters
Preptin is a reminder that the pancreas, appetite, bone and blood sugar behave as one connected system rather than separate chapters. It is also one reason we pay attention to protein intake and bone health when someone loses a lot of weight quickly.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: September 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
