IGF-1 LR3

What it is

IGF-1 LR3 is what the growth hormone peptides are trying to raise, delivered directly and built to last all day. Run properly it gives fuller muscles, faster recovery between hard sessions and a lean-while-eating effect; run carelessly it drops your blood sugar on the gym floor.

This is for experienced lifters who have squeezed what they can from training, food and the gentler peptides, and want a stronger push on muscle and recovery for a short block. It also gets used by people recovering from a serious injury who want a body-wide repair signal. It is the wrong choice for a first peptide, for anyone who trains casually, and for anyone with a cancer history, because it tells cells everywhere to grow.

The first thing you feel is the pump: fuller, tighter muscles within days, with better vascularity. Appetite often climbs. Over a four-week run most people see a noticeable change in fullness and recovery, and some fat loss if their diet is in order, with real but modest size gains; it is not a steroid cycle and does not pretend to be. The effect fades within a week or two of stopping. If you do not train hard during the run, you will have paid for a pump and some hunger.

The dose is tiny: 20 mcg to start, 30 to 40 mcg standard, 50 mcg at most, once a day, subQ. Timing is a preference; many do it post-workout with a meal, some pre-workout. The non-negotiable is carbohydrate: it pushes glucose into muscle fast, and a fasted dose followed by a workout is how people end up shaky, sweating and confused. Eat, or have juice on hand. Keep runs to 30 days at most, then about as long off, for two reasons: IGF-1 receptors become less responsive with steady exposure, and it pushes growth signals and blood sugar harder than anything else here. A 1 mg vial at 30 to 40 mcg is about four weeks, so one vial is one cycle; at 20 mcg it stretches to seven. The classic mistake is treating it like a GH peptide and running it for three months.

The honest evidence picture is animal data on muscle and tissue growth plus a long history of use, and almost no human trials of this specific long-acting version. Native IGF-1 is well studied as a medicine for children who cannot make it, which tells us plenty about the side effects (low blood sugar, swelling, jaw and joint growth at high doses over long periods) and nothing about short cycles for muscle. It is not an approved product anywhere.

If you want gentle and sustainable, use Ipamorelin or CJC-1295 and let your own body make the IGF-1. If you want growth in one specific muscle after a tear, MGF or PEG-MGF is the local version of the same idea. Skip IGF-1 LR3 entirely if you are diabetic, on insulin, have any cancer history, or have eye problems from diabetes; none of those are worth the trade.

What people use it for

How it works

Safety, in brief

The full picture — stop signs and who should talk to a doctor first — is on the dosing guide.

Sources

The labels and studies behind this page. Each link opens the original on PubMed, DailyMed or ClinicalTrials.gov.

1. Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated ratsTomas et al., Biochem J 1992 · Study
2. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injectionTomas et al., J Endocrinol 1996 · Study
3. IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeysTomas et al., J Endocrinol 1997 · Study
4. Increlex (mecasermin) prescribing informationDailyMed: Increlex (mecasermin) · Label