- Access
- Grey market
- Cost / month
- ≈ €36–140
- researchers' estimate; no listing to price
Felt in 2–4 weeks
Builds over days or weeks of regular use rather than with each dose.
24 user reports
Glowing 2Positive 7Mixed 5Nothing 5Negative 4Bad reaction 1r/moreplatesmoredates· · 17 upvotesOriginal ↗
So I started cycling it a little under a year ago. 6 weeks on 4-6 off. And lemme tell ya I’ve never had a more potent driver for just straight lean mass.
GlowingRecovery · about a year, 6 weeks on / 4-6 off
powerlifter on testosterone cypionate and EQ (about 750 mg/week) with arimidex; injects right after training with carbs and protein
r/BodyHackGuide· · 1 upvotesOriginal ↗
with the igf I’ve been able to gain weight and 2 cm of height because of my young bone age.
GlowingRecovery · 35 mcg 5x/week · 1 month
21-year-old hard-gainer with open growth plates ('young bone age'); others told him he risks diabetes, he says he monitors blood sugar
r/BodyHackGuide· · 7 upvotesOriginal ↗
Yeah I didn't notice anything ether just slightly a better pump
NothingRecovery
- Strict case
- A potent, long-acting IGF-1 receptor agonist with no human data at all: it accelerated tumour growth in mice, the same receptor causes hypoglycaemic seizures and carries a malignancy warning on the approved IGF-1 drug, and every vial is grey-market.
- Users report
- Split reports. Fans describe big pumps, fuller muscles, faster recovery and quick strength gains, often within 2-3 weeks. One user noticed less pain from a long-standing shoulder strain, and one 21-year-old says he gained weight and 2 cm of height. Most positive reports come from people also on testosterone, anavar, HGH or GLP-1s, so the effect cannot be separated out. Common downsides are water weight and puffiness, lethargy, tension headaches, intense soreness, light-headedness and hypoglycaemia symptoms when dosed without carbs; users keep dextrose or gummy bears to hand. There was one ER visit for a racing heart (normal ECG) and one report of a swollen prostate. At least one 17-year-old reports taking it, and younger teens keep asking about it. Felt nothing: About a fifth of first-hand reports felt nothing beyond a pump, and sceptics in every thread call it a waste next to growth hormone; a few blame degraded or fake vials, since it breaks down quickly once mixed..
- Best effects
- Big muscle pumps and fullness · faster recovery between sessions · quick strength gains (largely water in some reports) · lean-mass gain, mostly reported on top of steroids
- Downsides
- Hypoglycaemia (shaky, faint, 'felt like crap' when taken fasted) · water retention and puffy face in the first weeks · lethargy, tension headaches · severe next-day soreness in some · tolerance after 3-4 weeks, so it is cycled · expensive for what users get
- Watch
- Strong IGF-1 receptor activation that IGF-binding proteins barely hold back: accelerated tumour growth in a mouse cachexia model; theoretical promotion of existing or undiagnosed cancers · Hypoglycaemia, potentially severe: it is 2-3 times more potent than IGF-1 at lowering glucose in animals, and the approved IGF-1 drug causes hypoglycaemic seizures · Organ and soft-tissue growth seen with IGF-1 therapy (tonsils, spleen, kidneys, facial soft tissue) and with LR3 in rat gut · Never tested in humans; a His-tagged lab reagent has been found in a black-market vial
- Evidence
- Animal only — No human study of IGF-1 LR3. It was developed around 1990 in Adelaide, is sold mainly as a cell-culture reagent, and was tested only in rats, pigs and marmosets. The closest human data come from full-length IGF-1 (mecasermin, Increlex), which is a different molecule: shorter acting and held in check by binding proteins.
- Caveat
- No human pharmacokinetic or dosing data exist, so every community dose is extrapolated from cell-culture potency and bodybuilding forums. Reddit sentiment is heavily confounded by steroids and GLP-1s taken at the same time, and users report that LR3 barely moves a standard IGF-1 blood test, so they cannot check that a vial is active.
- Typical use
- Community dosing is 20-100 mcg/day subQ or IM, usually after training with 0.5-1 g of fast carbs per mcg, for 4-8 weeks then the same time off. Never fasted. Users report 27–60 mcg/day (median 30 mcg, n=7).
- Getting it
- Research-peptide vials only; it has never been a medicine anywhere. Usually reconstituted in 0.6% acetic acid because it degrades fast in bacteriostatic water. Banned in sport by WADA (S2).
- Stacked with
- Testosterone, anavar and other steroids: Most of the strongly positive reports come from people running it on top of a steroid cycle. · HGH or CJC-1295/ipamorelin: Often run alongside to offset feedback suppression of the user's own GH; many commenters say HGH alone is cheaper and better. · Retatrutide or tirzepatide: Added during or after a GLP-1 cut to hold muscle; users on both report hypoglycaemia crashes and sugar cravings. · PEG-MGF: An old forum protocol alternates weeks of LR3 and PEG-MGF; no data supports it.