The messenger that does the growing while growth hormone takes the name — most signals in the body are relayed before they act.
Identity
- Class
- Single-chain growth factor (70 aa)
- Source
- Liver (GH-stimulated) and local tissues
- Receptor
- IGF-1 receptor (IGF-1R, a receptor tyrosine kinase)
Key properties
Evidence floorClinicalREF1CLIN1Approximate values for the native hormone; engineered analogs are often deliberately larger and far longer-acting. Each figure carries its own provenance tier, and the floor is the weakest of them - the Standard.
Mechanism
GH stimulates hepatic IGF-1, which carries out much of GH's tissue-growth effect and feeds back negatively on the pituitary and hypothalamus to restrain further GH release. IGF-1 circulates bound to IGF-binding proteins that modulate its availability.
Reference notes
- IGF-1 is the principal effector of GH's growth-promoting actions.
- Its negative feedback is why sustained secretagogue exposure does not produce limitless GH.
- IGF-binding proteins are a key layer controlling how much IGF-1 is bioavailable.
Regulatory status
United States · reviewed September 2026- Basis
- Mecasermin (Increlex, 2005) approved for severe primary IGF-1 deficiency.
Status describes the molecule as a drug substance under US law and is an editorial reading of the public record — approvals, trial registrations, and the FDA 503A bulk-substances list. It is not legal advice and it changes; the review date above is the last time the table was checked. Other jurisdictions are noted only where they differ materially.
Common questions
- What is Insulin-like growth factor 1 (IGF-1)?
- The hepatic mediator of growth hormone's anabolic effects. Structurally it is Single-chain growth factor (70 aa).
- How does IGF-1 work?
- GH stimulates hepatic IGF-1, which carries out much of GH's tissue-growth effect and feeds back negatively on the pituitary and hypothalamus to restrain further GH release. IGF-1 circulates bound to IGF-binding proteins that modulate its availability.
- How strong is the evidence for IGF-1?
- PeptideHormone grades IGF-1 at the "Established" evidence tier — its mechanism and core effects are settled across the peer-reviewed literature. It is catalogued as an endogenous signal the body produces itself, and the tier is an editorial judgment about the public literature that can change as the science does.
- What is the half-life of IGF-1?
- The reported circulating half-life of IGF-1 is ~12–16 h bound to IGFBPs (~10 min free).
- Is IGF-1 FDA-approved?
- Yes — as of September 2026, IGF-1 is an approved prescription medicine in the United States. Mecasermin (Increlex, 2005) approved for severe primary IGF-1 deficiency. Status is US-centric and can change; check the FDA record for the current position.
In the literature
Live registry counts · retrieved- Ph 118
- Ph 255
- Ph 334
- Ph 422
Searched as Insulin-like growth factor 1, IGF-1, mecasermin. Counts are search hits from the primary registries, not a curated set and not a grade – a measure of how much work exists on IGF-1, not how it turned out.
Selected literature
Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.
- 1.Regulation and function of insulin and insulin-like growth factor receptor signalling · Nature reviews. Molecular cell biology, 2025 · PMID 39930003
- 2.Insulin-Like Growth Factor-1 and Neuroinflammation · Frontiers in aging neuroscience, 2017 · PMID 29163145
External references
IGF-1 in the public knowledge graph — the same entity resolved across the authoritative chemistry and protein databases.