★ Growth Hormone

IGF-1 LR3

Growth Hormone · 0.1mg × 10 vials

In plain terms: IGF-1 LR3 is a research compound - injectable, fast-acting and well studied.

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Quick Start
🧪
Format
Injectable (reconstituted) · 0.1mg × 10 vials
🎯
Who it's for
bulking research
💉
How it's run
20-40 mcg subcutaneous, once daily
When you'll notice
pumps + recovery within first week
Pricing
$85from · kit of 10
US: 2-5 day · Intl: 7-14 day
+ $40 ship · singles $20 · free over $1k per tier
0.1mg × 10 vials$85
1mg × 10 vials$365
Order / Consult on Telegram →
~20-30 hr
Half-life
4-6 wk on / 4 off
Cycling
pumps + recovery within first week
First effects
growth-hormone
Class
Overview

What Is IGF-1 LR3?

IGF-1 LR3 (Long R3 IGF-1) is a synthetic, modified version of insulin-like growth factor 1, the downstream peptide that does most of the actual tissue-growth work after growth hormone signals the liver. Two changes from native IGF-1: an arginine substitution at position 3 (replacing the glutamic acid, hence "R3"), and a 13-amino-acid extension on the N-terminus (the "Long" part), bringing total length to 83 aa vs the 70 of endogenous IGF-1. Both changes serve one purpose: dramatically reduce binding affinity to the six IGF binding proteins (IGFBPs) that normally trap circulating IGF-1 and shut it down within minutes. The result is a molecule that escapes IGFBP sequestration, stays free in circulation, hits IGF-1 receptors on muscle and other tissues for ~20-30 hours instead of ~10 minutes, and is roughly 2-3x more potent than native IGF-1 on a per-molecule basis. Downstream, IGF-1R activation drives the PI3K/AKT/mTOR pathway (the master switch for muscle protein synthesis), MAPK signaling for satellite cell proliferation, and GLUT4 translocation for glucose uptake. Translation: protein synthesis up, satellite cells (the muscle stem cells that fuse into existing fibers) activated, nutrient partitioning toward muscle, glucose pulled into muscle cells aggressively. The aggressive glucose uptake is also the source of the hypoglycemia risk that defines the dosing rules.

Protocols

Typical dose ranges by experience level - educational reference. Message us and we tailor it to you.

Protocol20-40 mcg subcutaneous, once daily
Frequency1x per day, ideally post-workout on training days, same time of day on rest days
Duration4 weeks on / 4 weeks off, run one cycle and reassess

Eat a carb-containing meal 15-30 min pre-injection. New researchers commonly report a "head-rush" or lightheaded feeling 20-40 min post-injection if blood glucose drops, that's the signal to eat more carbs around the dose next time. First-cycle reads are subtle, mostly pump quality, recovery between sessions, and ~2-4 lb scale weight (largely glycogen + water). Don't chase dramatic visual changes on a 4-week first cycle.

Protocol40-60 mcg subQ, once daily
Frequency1x per day, post-workout on training days
Duration4-6 weeks on / 4 weeks off

This is the "working dose" band where most users see visible recomp effects when paired with a hypertrophy training block and surplus calories. Bodyfat shifts are modest, the compound is muscle-anabolic, not lipolytic. Hypoglycemia management is non-negotiable at this band, especially if researcher trains fasted. Lower-back/joint pain is a moderate-frequency report at 50+ mcg, often described as a "growing pains" sensation, generally resolves at dose reduction.

Protocol60-100 mcg subQ, once daily (some split AM/PM at 50+50)
Frequency1x per day or split BID
Duration4-6 weeks on / 4 weeks off, hard cap. Do not run continuously.

100 mcg is the practical ceiling. Doubling above this does not double results, the dose-response curve flattens hard above 80 mcg, and side effect severity rises near-linearly past that point. Advanced researchers running 80-100 mcg almost always stack with HGH or CJC+Ipa for synergistic GH-axis activation and report the IGF-1 LR3 portion is what drives the recovery and visible muscle fullness rather than the GH portion (which contributes more to fat loss and connective tissue).

What To Expect
pumps + recovery within first week
noticeable change
hypertrophy reads at 3-4 weeks
noticeable change
Side Effects

Straight talk - what people actually report, and what the studies measured.

What users report
From forums, Discord & TikTok
  • Hypoglycemia/blood sugar crashes: the most-reported side effect, manageable with pre-injection carb meal; users who skip the carbs and inject fasted report dizziness, sweats, brain fog 30-60 min post-dose
  • Lower back / joint pain: moderate-frequency, "growing pains" sensation at 50+ mcg, often resolves at dose reduction or with hydration + electrolyte focus
  • Pump quality / vascularity: reported by majority of users within first 1-2 weeks, often the first sign the compound is working
  • Numbness/tingling in fingers: lower-frequency report, similar to carpal tunnel sensation from water retention + IGF-1 mediated tissue effects
  • Gut growth ("IGF gut"): the bodybuilding-forum folk-claim that high-dose IGF-1 LR3 causes visceral organ growth and a distended abdomen. Reality is the "GH gut" / "palumboism" look is far more often attributable to high-dose HGH + insulin + slin pin use, not IGF-1 LR3 at research doses (20-100 mcg). At standard doses this is largely a myth.
  • Localized growth at injection site: pure folklore. IGF-1 LR3 distributes systemically within minutes. Bilateral biceps injection does not selectively grow biceps. Users who think they see local growth are seeing transient pump + placebo.
  • Hair shedding: occasional reports, generally tied to rapid recomp + nutritional gaps rather than a direct drug effect
  • - Divergence: Forum dosing (20-100 mcg/day for 4-6 weeks) is far below the mecasermin clinical doses (60-120 mcg/kg twice daily, i.e., 5-10 mg/day for a 70 kg adult) used for severe primary IGFD pediatric patients. AE rates in research-tier dosing are dramatically lower than published RCT rates for that reason. Hypoglycemia is the AE that translates across both contexts.
What the studies show
Measured in clinical trials
  • Hypoglycemia: dose-dependent, well-documented in mecasermin (recombinant IGF-1) trials, ranges from mild (lightheadedness, sweating) to severe (syncope) at supraphysiologic doses; LR3 variant raises free-IGF activity further by escaping IGFBP buffering
  • Injection site reactions: erythema, mild itching at 5-15% in mecasermin studies
  • Lymphoid hypertrophy: tonsillar/adenoid growth documented in pediatric mecasermin trials at therapeutic doses, less reported at research-tier doses
  • Headache: 10-15% in clinical use
  • Theoretical/long-term: chronically elevated circulating IGF-1 is associated in epidemiology with increased risk of breast, prostate, colorectal, and thyroid cancer (Oxford 400k cohort, 2020). This is a chronic-elevation signal, not a 4-6 week pulse signal, but worth flagging for researchers with strong family cancer history.
The Research

Peer-reviewed studies and clinical guidelines - tap any to read the source.

PubMedLong R3 IGF-1 infusion stimulates organ growth, guinea pig model (PMID 7561636)

](https://pubmed.ncbi.nlm.nih.gov/7561636/) - foundational paper on LR3 variant pharmacology and IGFBP-evasion

Read study ↗
PubMedIGF-1 and its monitoring in medical diagnostic and in sports (PMC7913862)

](https://pmc.ncbi.nlm.nih.gov/articles/PMC7913862/) - comprehensive review of IGF-1 biology + sports use + WADA detection context

Read study ↗
PubMedEffect of IGF1 on Myogenic Proliferation and Differentiation of Bovine Skeletal Muscle Satellite Cells via PI3K/AKT (PMC11675145)

](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11675145/) - satellite cell activation mechanism

Read study ↗
PubMedmIGF-1-Induced Hypertrophy and Ca2+ Handling in Differentiated Satellite Cells (PMC4168228)

](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4168228/) - hypertrophy pathway evidence

Read study ↗
PubMedObesity and endocrine-related cancer: the role of IGF-1 (PMC9899991)

](https://pmc.ncbi.nlm.nih.gov/articles/PMC9899991/) - IGF-1 + cancer risk biology

Read study ↗
Clinical guidelinesOxford 400k cohort, IGF-1 and cancer risk

chronic elevation cancer signal

Read study ↗
+ 4 more studies & references
From The Community

Aggregated sentiment from public forums & socials - real-world reports, not individual endorsements.

SSwolverine IGF-1 LR3 b

Hypoglycemia/blood sugar crashes: the most-reported side effect, manageable with pre-injection carb meal; users who skip the carbs and inject fasted report dizziness, sweats, brain fog 30-60 min post-dose

SSwolverine IGF-1 LR3 s

Lower back / joint pain: moderate-frequency, "growing pains" sensation at 50+ mcg, often resolves at dose reduction or with hydration + electrolyte focus

PPeptide Catalog IGF-1

Pump quality / vascularity: reported by majority of users within first 1-2 weeks, often the first sign the compound is working

TTruth About Peptides I

Numbness/tingling in fingers: lower-frequency report, similar to carpal tunnel sensation from water retention + IGF-1 mediated tissue effects

PPeptIQ IGF-1 LR3 muscl

Gut growth ("IGF gut"): the bodybuilding-forum folk-claim that high-dose IGF-1 LR3 causes visceral organ growth and a distended abdomen. Reality is the "GH gut" / "palumboism" look is far more often attributable to high-dose HGH + insulin + slin pin use, not IGF-1 LR3 at research doses (20-100 mcg). At standard doses this is largely a myth.

PPeptideDeck IGF-1 LR3

Localized growth at injection site: pure folklore. IGF-1 LR3 distributes systemically within minutes. Bilateral biceps injection does not selectively grow biceps.

Common Questions
SubQ (intramuscular sometimes used by advanced researchers; site-specific local growth from IM is folklore, the molecule distributes systemically within minutes regardless of injection site). 20-40 mcg subcutaneous, once daily
pumps + recovery within first week, hypertrophy reads at 3-4 weeks
Most users run a recovery (PCT) protocol after a cycle to restore natural production and hold onto gains. Message us for the standard protocol.
A popular pairing is IGF-1 LR3 + CJC-1295 + Ipamorelin. See the Protocols section, or ask us for a stack built around your goal.
Yes. Every batch is third-party lab tested - request the COA on Telegram and we send it over.
Safety & Contraindications

Hard stops

  • Active cancer or recent cancer history (any tissue, IGF-1 is mitogenic across most epithelial tissues)
  • Strong personal history of thyroid, breast, prostate, or colorectal cancer
  • Active diabetic retinopathy (IGF-1 may worsen)
  • Pregnancy or breastfeeding
  • Acromegaly or any active GH-axis tumor
  • Severe hypoglycemia history or untreated reactive hypoglycemia
  • Pediatric use outside of physician-supervised mecasermin protocols

Caution flags

  • Type 1 or insulin-dependent type 2 diabetes (will need significant insulin dose adjustment, do not run without endocrinologist)
  • Strong family cancer history in IGF-sensitive tissues
  • Severe hepatic or renal impairment
  • Researchers training fasted (the population most likely to hit hypoglycemia)
  • Sleep apnea (IGF-1 mediated soft tissue growth may worsen)

Stacking conflicts

  • Caution with insulin/slin pins (hypo risk compounds, advanced researchers only)
  • Caution with MK-677 (additive insulin resistance + IGF-1 elevation, monitor glucose)
  • No clean conflict with the rest of PP's catalog (BPC, TB, CJC+Ipa, MGF, HGH, tesamorelin, GHK-Cu all stack fine)
Is It Right For You?

✓ Good fit

  • bulking research
  • recomp goals
  • post-cycle muscle preservation
  • advanced GH-axis stackers
  • customers already running CJC+Ipa or HGH wanting to amplify
  • plateau breakers in hypertrophy blocks

✗ Not a fit

  • fat-loss-only goals
  • cancer history
  • T1D
  • beginner peptide researchers with no GH-axis experience
  • customers who can't manage a carb meal around injection timing
  • sedentary researchers
  • anti-aging customers looking for a "general health" peptide

Administration & Storage

Route: SubQ (intramuscular sometimes used by advanced researchers; site-specific local growth from IM is folklore, the molecule distributes systemically within minutes regardless of injection site)

Injection site: rotate abdomen and outer thigh subQ; if researcher insists on IM the "bilateral injection into trained muscle group post-workout" protocol exists in the forum literature but local effect is unproven

Storage: refrigerated, ~14-21 days after reconstitution (IGF-1 LR3 is less stable post-recon than the GLP-1s, use sooner). Pre-recon vials: refrigerated, freezer for long storage

Notes: Always eat a meal containing carbs 15-30 minutes before injection. Hypoglycemia is the #1 acute risk and it's real, not theoretical. Most common admin window is immediately post-workout (when nutrient partitioning is most favorable and glycogen-uptake bias is highest), but timing-around-workout matters less than people claim. Slow-wall injection technique (1 ml over 20-30 seconds) is recommended at reconstitution to avoid protein denaturation from shear stress. Do not shake the vial, swirl gently.

All products sold for research purposes only. Not for human or animal consumption. Must be 21 or older to purchase. By placing an order you confirm compliance with all applicable local laws and regulations.