IGF-1 LR3
Also known as Long R3 IGF-1
A long-lasting, lab-made version of IGF-1 — the growth factor that growth hormone works through. Made for lab research.
Quick facts
- Status
- Not an approved medicine
- Evidence
- Preclinical (cell culture)
- Taken as
- Injection
- Common sizes
- 1 mg
- Category
- Growth factor analogue (experimental)
How it works
It switches on the IGF-1 receptor, which tells cells to grow. Changes to the molecule make it last much longer than natural IGF-1.
What people use it for
Muscle growth (claimed)
What the research shows
Studied in cell cultures, not in people.
Side effects & risks
- Low blood sugar, which can be dangerous
- Possible risk of feeding tumour growth
- Banned in sport
Is it legal?
Not an approved medicine in the EU, UK or US. In most countries it is illegal to sell it for use in people. Products labelled "research use only" are not checked for quality or purity. (The approved IGF-1 medicine is mecasermin, which is a different product.) Prohibited in sport (WADA Prohibited List).
Storage & safe handling
- Mix with bacteriostatic water: let it run slowly down the inside of the vial and swirl gently — never shake.
- Store the mixed vial in the fridge and follow the use-by period on the label.
- Wipe the vial top with alcohol and use a new sterile needle and syringe every time.
- Rotate injection sites so the same spot is not used again and again.
- Put used needles in a sharps container, not the household bin.
- Get medical help for redness that spreads, fever, swelling or trouble breathing.
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Sources: WADA Prohibited List; product information for mecasermin (Increlex) for comparison.
Last updated 12 October 2026. Information — not medical advice. PepTimer does not replace a doctor. Many peptides are not approved medicines in the EU, UK or US. Talk to a qualified healthcare provider before starting, changing or stopping any treatment.
Last updated 12 October 2026. Information — not medical advice. PepTimer does not replace a doctor. Many peptides are not approved medicines in the EU, UK or US. Talk to a qualified healthcare provider before starting, changing or stopping any treatment.