STUDresearch · Peptide
IGF-1 LR3
Also known as
Long R3 IGF-1 · Long Arg3 IGF-1 · Long-R3-IGF-I · LONG® R³ IGF-I (cell-culture reagent class) · IGF1 LR3 · IGF-1 Long R3 · LR3 IGF-1 · LR3-IGF-1 · Long arginine 3-IGF-1 · IGF-1
Community talk. May be wrong. Not medical advice. Not a protocol. Not for human or animal use.
Peptide
Lots of talk
Mixed
SubQ / IM
Growth factors
Mixed — SubQ is the systemic forum default; IM site use is debated, and no human LR3 half-life establishes long or local exposure.
What people say
IGF-1 LR3 is an 83-amino-acid IGF-I analogue engineered for research and cell culture with low binding-protein affinity. Adult physique use is gray-market practice, not a validated human treatment.
Doses people talk about
These are unverified adult self-reports, not clinical dose-finding. Training, diet, source identity and co-compounds materially change interpretation.
How it may feel
One six-week report described modest pumps in weeks one to two, then endurance and strength around weeks three to four and fuller appearance by weeks five to six, with water retention, sore joints, transient hand tingling and higher cholesterol. Other users report no value or no glucose symptoms.
Detailed six-week self-report30 / 40 / 50 mcg/day
Two weeks at each amount; the author preferred 40 mcg, reported effects after week three and used tesofensine concurrently.
Repeated-cycle self-report35 mcg/day
One commenter described 35 mcg per dosing day with two days off each week, in four-to-six-week blocks separated by three-to-four weeks off over a year, and reported no sides; macros and five-day training were major confounders.
2026 question and report contrast20–200 mcg/day
The 20 mcg/day figure came from a question, not the respondent's experience; a separate respondent claimed 200 mcg without fasting symptoms, while another reported no value after a three-week run.
Half-life & effect duration
- Half-life in the body
- Community estimateAbout 20–30 hours
- Felt duration people report
- One 6-week logPumps in weeks 1–2; endurance in weeks 3–4; fullness in weeks 5–6
- After stoppingTingling resolved within days in that account
- Other accountsPumps or recovery claims, no value, or no low-blood-sugar feeling
Cycles people discuss
Community records describe short daily or five-days-per-week blocks, commonly three to six weeks, followed by time off. Repeated use over a year also appears, without controlled long-term safety evidence.
Timing
Preserved community notes describe post-workout use and morning-with-food use on rest days, with concern about hypoglycemia around fasting or bedtime. These are reported habits, not a validated schedule or a measured human half-life.
Stacks
HGH, secretagogues, insulin, AAS, DES and MGF-family products dominate LR3 stack talk. A detailed six-week account still included tesofensine, so even apparently simple reports are not clean single-agent evidence.
Access talk
Three names, three products: cell-culture LONG R3 reagent, gray 1 mg “IGF-1 LR3” vials, and prescription mecasermin. Do not treat a research vial as Increlex.
Labs people mention
Glucose is the real-time scoreboard, not a vanity IGF-1 printout. Finger-stick or CGM around the first doses is what 2025–26 hypo threads actually compare.
Watch for
Glucose effects / uncertainty: Hypoglycemia is a serious IGF-class concern, but inspected LR3 accounts conflict: one six-week 30–50 mcg/day report kept fasting glucose and A1C in range, while another claimed no symptoms even at 200 mcg fasted. Shaking, sweating, confusion, blurred vision, seizure or loss of consciousness remain emergency symptoms; these anecdotes do not establish safety.
Tap a line to jump into the full notes. Research only — may be wrong.
Timing context & sources
Half-life in the body
The repeated 20–30-hour human LR3 half-life was not established by the checked primary evidence.
Rat clearance work associates poor binding with altered and sometimes faster clearance. Rat anti-doping work detected LR3 degradation products up to 16 hours, which is not an intact-parent half-life.
No human LR3 concentration-time study; rat species/route mismatch; metabolite detectability cannot be converted into parent exposure or gray-market product kinetics.
- Gillespie et al. — Plasma clearance of IGF-I, des-(1-3)IGF-I and LR3IGF-I (opens in a new tab)Abstract: rat chronic-renal-failure model; total LR3IGF-I clearance increased and reduced 150-kDa-complex binding was associated with increased analogue degradation.Rat disease model and abstract-level quantitative detail; does not provide human LR3 PK or validate the 20–30-hour claim.
- Thomas et al. — Detection of LongR3-IGF-I and other IGF-I analogues (opens in a new tab)Abstract: validated immunopurification/high-resolution-mass-spectrometry method after rat IM administration; identified LR3 degradation products, one detectable up to 16 hours.Rat anti-doping detectability study; metabolite detection is not an intact-parent half-life or human exposure curve.
Felt duration people report
One six-week report placed modest pumps in weeks one to two, endurance in weeks three to four and fullness in weeks five to six; tingling resolved within days after stopping.
A separate 2026 report described pumps and recovery without an amount, while others reported no value or no hypoglycemic feeling.
Unverified products, self-report, changing amounts, training/diet effects and tesofensine co-use; course-time changes do not establish single-dose duration.
- r/Peptides — IGF-1 LR3 experience and same-author follow-up (opens in a new tab)Original six-week log: 30, 40 and 50 mcg daily phases, weeks 1–6 effects, water retention, joint soreness, hand tingling resolving after stopping, cholesterol/LDL increase, stable fasting glucose/A1C and tesofensine co-use; later follow-up discusses maintained modest gains.Single self-report, claimed prescription then research-chemical product, changing amounts, no product assay, training/diet and tesofensine confounding.
- r/Peptidesource — 2026 LR3 experience (opens in a new tab)Question cites 20 mcg/day; one respondent reports pumps/recovery during a short solo run and says retention depended on continued diet and training, without giving amount or dates.Sparse unverified self-report; no product test, measurements or amount for the experience reply.
- r/Peptidesource — 2026 LR3 muscle-building experiences (opens in a new tab)Visible replies conflict: one claims 200 mcg while fasting without symptoms; another reports no value after three weeks; others prefer HGH and mention bloating concerns.Anonymous, unverified products and amounts; no objective glucose, body-composition or product-identity evidence.
What people say
- Hypertrophy / size: Fuller muscle, easier progressive overload, and multi-week size claims on high-food bulk logs — heavily confounded by surplus, training, and stacks. forum
- Pumps / fullness: Early “fuller” look with post-workout carbs is one of the most repeated early signals; water vs true contractile tissue is hard to split. forum
- Recovery feel: Less next-day soreness and better training continuity during hard blocks — sleep, food, and co-compounds often share credit. forum
- Nutrient partitioning: Carbs and protein “land better” peri-workout / post-dose — self-report and insulin-like mechanism talk, not controlled LR3 physique RCTs. anecdote
- Satellite-cell / hyperplasia lore: Community frames LR3 as supporting satellite-cell activation and possible fiber-density gains over pure myofibrillar swelling; this is pathway storytelling more than measured human fiber-count proof. forum
- Site injection claims: IM into lagging/trained muscles for regional fullness — anecdote-heavy; long half-life means local-only effect is partial at best. forum
- Anti-catabolic hold: Better size retention on cuts or downtime in logs — hard to separate from diet, GH-axis partners, and AAS. forum
- Vs GH-raised IGF-1: Positioned as a more direct receptor hit than HGH, MK-677, or CJC/Ipamorelin alone (those raise endogenous IGF-1 upstream). forum
- Stack halo problem: Very often stacked with HGH, insulin, AAS, DES, PEG-MGF, or secretagogues — single-agent credit is unreliable. forum
- Preclinical backdrop: Infused LR3 analogs more potent than equimolar native IGF-1 for body weight, organ growth, and anti-catabolic effects in rat models (e.g., Tomas et al. class work often cited ~1.5–2× or higher potency in catabolic settings). animal
- Cell-culture heritage: LONG R3 IGF-I is a established serum-free media supplement because low IGFBP binding keeps free activity high in culture — explains industrial “why it exists,” not gym efficacy. trial
Doses people talk about
- Assessment / start band: ~20–30 mcg once daily (often post-workout) to gauge hypoglycemic response before titrating. forum
- Common working band: ~30–50 mcg once daily — modal “sweet spot” in many bodybuilding peptide guides and threads. forum
- Moderate extension band: ~40–80 mcg/day appears in broader protocol tables; diminishing returns and sides often discussed above ~50–60 mcg. forum
- Upper community band: ~80–100 mcg/day (sometimes framed 50–100 mcg aggressive) in advanced logs — hypo risk and side frequency rise; not a beginner target. forum
- Smaller / female discussion: ~10–20 mcg/day sometimes discussed as a lower heuristic band — not trial-stratified dosing. forum
- Training-day vs every day: Many run daily for the short block; others dose training days only (~5×/week) and skip or food-pair rest days — both appear in charts. forum
- Timing (default): Post-workout with planned carbs/protein is the dominant rationale (receptor/training stress + lower hypo risk). forum
- Rest-day timing: Morning-with-food is common when dosing rest days; pre-bed dosing is widely discouraged (overnight hypo harder to catch; endogenous nocturnal GH pulse suppression talk). forum
- Carb pairing talk: Protocol summaries often pair dose with ~30–50 g fast carbs within ~30 minutes and a protein-forward meal in the hour after; never intentionally fasted. forum
- Missed dose: Community/protocol consensus is skip and resume next day — do not double-dose (additive hypo risk). forum
- Source uncertainty: Gray-market labels ≠ verified identity, purity, or stated mcg; underdosing/mislabel confounds every log. forum
- 2025–26 cap talk: Protocol sheets still copy 20 → 40 → 50 mcg over weeks and treat ~50–60 mcg as the “more is mostly hypo” ceiling — not a new trial. forum
- Training-days-only 2026: Some logs skip rest days to cut hypo exposure and vial cost; others run daily for the short 3–4 week block. forum
- Not a 100 mcg beginner chart: 80–100 mcg/day still shows up in aggressive logs and some 2025 Reddit cycle posts; hypo and “this is a tiktok dose” pushback are the replies. forum
- Framing: Community and research-chem protocol ranges only — not medical advice, not clinical prescriptions, not validated athletic protocols. No human trial has established an LR3 hypertrophy dose. forum
- Vs clinical mecasermin (context only): Increlex is weight-based BID SubQ native IGF-1 for pediatric severe primary IGFD (start ~0.04–0.08 mg/kg BID, max 0.12 mg/kg BID with food) — not an LR3 bodybuilding chart and not transferable as “safe adult mcg.” trial
How it may feel
- 0–2 hours post-dose: Usually no “buzz”; early focus is glucose — shakiness, sweat, hunger, lightheadedness if carbs are low or dose is aggressive. forum
- ~30–90 minutes: Community hypo windows often cluster here; protocol guides stress carbs already planned, not rescue-only after symptoms. forum
- Days 1–3: Little visual change; logs emphasize learning hypo response, injection technique, and never dosing fasted. forum
- Days 3–7: Fuller pumps with post-workout carbs in some logs; others mainly manage glucose and see nothing cosmetic yet. forum
- Weeks 1–2: Checkpoint — is pump/recovery worth daily injections + carb vigilance? Non-responders recheck surplus, training, sleep, source. forum
- Weeks 2–3: Waist/scale water and “soft” fullness watched; progressive unexplained abdominal expansion is a community stop flag (organ-growth worry). forum
- Weeks 2–4: Subjective size/fullness claims most often land here when they land; not a steroid-like overnight flip. forum
- Weeks 4–6 (2026 sheets): Many charts hard-stop here for desensitization / organ-growth lore. Continuous month-plus runs are the “why is my waist weird” posts. forum
- If you only feel shaky: 2025–26 logs treat that as glucose, not “it’s working.” Carbs first, not a dose jump. forum
- TikTok-skepticism feel: 2025 MPMD-adjacent threads still call gray LR3 a scammer size peptide vs HGH; pumps-with-carbs is the remaining “I felt it” report when people feel anything. forum
- Week 1 monitoring focus: Fasting/symptom glucose checks; Increlex-adjacent human data show hypo events densest early in rhIGF-1 exposure — community mirrors that caution for LR3 starts. trial
Around the dose
- Clock: Post-workout with planned carbs is the 2025–26 default. Morning-with-food on rest days. Bedtime is widely treated as a hypo trap. forum
- Never fasted: Opposite of GHRP empty-stomach lore. LR3 is insulin-like — food around the pin is the hypo rule, not optional flavor text. forum
- Carbs in reach: Glucose tabs / juice in the same window as the pin is the usual “don’t be a hero” talk, especially first weeks and above ~50 mcg. forum
- Training: PWO timing is a habit, not a proven local-hypertrophy trick. Long half-life means the analog is still circulating the next day. forum
- Site vs SubQ: IM into the trained muscle is still argued on 2025–26 boards; the counter is 20–30 h activity = systemic spillover either route. forum
- Mix talk (no SOP here): Acetic-acid vs bacteriostatic-water is a loud 2025–26 handling fight (aggregation at neutral pH). This card still has no reconstitution chart. forum
- After: Eat the carbs you already planned. Don’t “see if you can fast through it.” forum
- GLP-1 / reta caution: Appetite suppression can hide the early hunger cue of a crash — extra glucose vigilance in those stacks. forum
Cycles people discuss
- Core rule in lore: Not a continuous lifestyle peptide — receptor desensitization and cumulative growth-pathway risk drive short blocks. forum
- Short / aggressive burst: ~10–14 days or ~21-day “on” then multi-week off appears in some hypertrophy camps. forum
- Common short block: ~3–4 weeks on, ≥4 weeks off minimum (often cited as the modal structure). forum
- Standard chart: ~4 weeks on / ≥4 weeks off. forum
- Extended community max: ~5–6 weeks on only after prior cycles showed acceptable glucose tolerance; off-time often ≥ on-time (e.g., 6 weeks off). forum
- 4–6 weeks on / 4–6 weeks off: Very common template across stacking guides; continuous multi-month use widely discouraged. forum
- Pulsed vs daily-within-block: Pulse around a hard mesocycle, or daily for a short defined block then hard stop — both discussed. forum
- Why off-time: Forums cite IGF1R downregulation / blunted response with unbroken exposure; recovery of sensitivity is lore-level, not routine receptor assays in gym users. forum
- Re-runs: Common on later bulks; no long-term safety database for repeated gray-market LR3 cycles. forum
- Stack-length asymmetry: GH secretagogues (CJC/Ipa, etc.) sometimes run longer than the LR3 window; LR3 is the shorter “cap” compound in those charts. forum
- Exit triggers discussed: Recurrent hypo despite food, progressive unexplained waist expansion, new severe headache/visual symptoms, or any concerning new growth/lesion — community stop flags, not a complete medical algorithm. forum
Timing
- Half-life claims (community + protocol guides): ~20–30 hours for LR3 and ~20–30 minutes for DES are widely repeated. No human LR3 PK study supporting the 20–30-hour figure was identified; rat studies instead show binding-dependent clearance and detectable metabolites, not a human parent half-life. forumanimal
- Once-daily rationale: Forum schedules commonly use once-daily LR3 and contrast it with more frequent DES site talk. A dosing interval is practice lore, not proof of parent-molecule half-life or day-to-day accumulation. forum
- Layering within a block: Daily doses may overlap residual activity day to day over a multi-week run. forum
- Glucose timing: Insulin-like disposal can appear within hours of a dose — carbs planned around injection, not only “if you feel bad.” forum
- Avoid bedtime window: Guides commonly keep dosing ≥2–3 hours before sleep to reduce overnight hypo risk and limit coincidence with natural nocturnal GH pulses (exogenous IGF-1 can feedback-suppress pituitary GH). forum
- Vs DES: DES = short/local burst IM post-workout; LR3 = long/systemic default — different tools, not interchangeable. forum
- Vs PEG-IGF / PEG-MGF: PEG extensions further change duration/localization talk; forum charts simplify these into “systemic LR3 vs local MGF/DES” boxes. forum
- Binding-protein context: LR3 has poor IGFBP affinity, which changes free activity and clearance. In rat research, reduced binding was associated with faster clearance or degradation in relevant comparisons; it does not prove a longer human plasma half-life. animal
- Vs mecasermin PK: Native rhIGF-1 (Increlex) has shorter clinical half-life context and BID clinical dosing — another reason not to copy pediatric mg/kg charts onto LR3 mcg plans. trial
- Detection note: Long R3-IGF-I and related analogs have published anti-doping detection approaches (immunopurification + HRMS class methods) — relevant for tested athletes. trial
More on what it is
- Mechanism talk: IGF1R tyrosine kinase → PI3K/Akt/mTOR (protein synthesis, glucose/AA uptake, anti-apoptosis) and MAPK/ERK (proliferation / satellite-cell talk); insulin-like glucose disposal is the same pathway that drives hypoglycemia. forum
- What it is: Synthetic 83-aa analog of human IGF-1 (native is 70 aa): Glu3→Arg3 (“R3”) plus a 13-aa N-terminal extension (“Long”); mass often listed ~9,111 Da. Engineered for research/cell culture (LONG R3 IGF-I class), not as an approved physique drug. trial
- Why people search it: Forums frame LR3 as a direct IGF-1-receptor analogue with longer activity than native IGF-1 and contrast it with HGH or secretagogues. The direct-receptor framing is mechanistic; the claimed human duration is not established. forumanimal
- Why longer/more free: Arg3 + Long extension sharply cut IGF-binding-protein (IGFBP) affinity (vendor/pharmacology literature often cites >100–1000× reduced IGFBP binding), so more peptide stays free at IGF1R. trial
- Evidence posture: Strong cell/animal IGF biology and industrial cell-culture use; adjacent human safety from rhIGF-1 (mecasermin / Increlex) in pediatric severe primary IGFD — but no large RCTs validating gray-market LR3 for adult hypertrophy. trial
- What it is not: Not HGH, not insulin, not a SARM, not mecasermin (native 70-aa rhIGF-1), not oral/topical product for these goals, not FDA-approved for muscle, recomp, or “anti-aging.” trial
- Regulatory / sport: Research-chem / gray-market peptide space for physique talk; WADA S2 peptide hormones/growth factors — prohibited in and out of competition; detection methods for Long R3-IGF-I exist in anti-doping literature. trial
Stacks
- HGH + LR3: Classic “GH axis” growth/recovery stack — dual attribution confounded; more glucose and growth-pathway load. forum
- CJC-1295 (often no DAC) + Ipamorelin + LR3: Popular peptide stack — secretagogues elevating endogenous GH/IGF-1 upstream, LR3 as direct post-workout receptor hit; timing usually separated (GHS fasted AM/bed; LR3 post-workout). Sample charts often show LR3 ~40–60 mcg PWO with Ipa ~100–200 mcg and CJC no DAC ~100 mcg bed-class doses (vendor charts vary). forum
- Sermorelin / other GHRH: Alternate upstream GH pulse support when CJC is not used. forum
- MK-677 + LR3: Oral GH-secretagogue + direct IGF analog — appetite/water from MK plus LR3 hypo risk; confounded recomp talk. forum
- Insulin + LR3 (advanced, high-risk): Nutrient-partitioning lore in hardcore forums; additive hypoglycemia — widely flagged as not beginner and often treated as avoid-outside-supervision. forum
- AAS bulks: LR3 layered onto steroid cycles in advanced camps; sides, source quality, and multi-drug confounds dominate. forum
- PEG-MGF + LR3: “Two-wave” recovery lore — PEG-MGF soon post-workout for early satellite-cell talk, LR3 hours later for differentiation/protein-synthesis talk; schedules vary and evidence is community-level. forum
- DES + LR3: Local short DES site shots plus systemic LR3 — complexity and glucose risk stack; not a starter protocol. forum
- BPC-157 (± TB-500): Recovery/soft-tissue support alongside LR3 hypertrophy blocks — different pathways; credit split. forum
- MOTS-c discussion: Some modern stack guides pair mitochondrial/insulin-sensitivity talk with LR3 to “buffer” metabolic stress — still research-chem lore. forum
- GLP-1 / retatrutide caution: Appetite suppression can mask early hypo hunger cues; community says extra glucose vigilance if combined for recomp. forum
- Training + surplus: Progressive overload and peri-workout carbs are repeatedly credited when logs look good — non-pharmacologic half of the stack. forum
Access talk
- Three names, three products: cell-culture LONG R3 reagent, gray 1 mg “IGF-1 LR3” vials, and prescription mecasermin. Do not treat a research vial as Increlex. forum
- Gray identity: Underfilled or wrong analog is the usual “no pumps / no hypo” suspicion before “non-responder.” forum
- Not on the July 2026 PCAC seven. trial
- Not a 503A “peptide compounding” story: LONG R3 IGF-I is an industrial cell-culture analog; mecasermin (Increlex) is the approved native IGF-1 drug for pediatric IGFD — different molecule, different legal shelf. trial
- WADA S2: Growth-factor analogs stay prohibited — not a secretagogue loophole. trial
Labs people mention
- Glucose is the real-time scoreboard, not a vanity IGF-1 printout. Finger-stick or CGM around the first doses is what 2025–26 hypo threads actually compare. forum
- IGF-1 assay caveat (loud 2025–26): LR3 is an analog. Standard IGF-1 immunoassays may miss it, partly cross-react, or read *lower* because exogenous IGF activity can feedback-suppress pituitary GH and liver-made IGF-1. A flat or falling IGF-1 does not prove the vial is dead. forumtrial
- Do not titrate LR3 to a forum “200–300 ng/mL sweet spot.” That number is secretagogue/rGH lore. On LR3, people watch glucose, waist, and whether pumps showed up with food. forum
- If IGF-1 explodes: people first ask whether GH, MK-677, or DAC-CJC is in the same month — LR3 is a poor explanation for a huge native-IGF-1 jump. forum
Storage notes
- No mix instructions here: STUDresearch does not list reconstitution, diluent volumes, or syringe unit charts. People reconstitute many different ways and vial labels differ — that content creates more confusion than clarity. forum
- Storage (general talk only): Unopened research products are usually kept cool, dry, and away from light per the seller label. Anything after first use is product-specific — follow the label, not a universal forum SOP. forum
- Acetic vs bac (identity, not a mix chart): 2025–26 vendor/Reddit handling posts treat dilute acetic acid as the anti-clump solvent and bac water as the sting-reducer people sometimes add in the syringe. Still not reconstitution math. forum
Watch for
- Glucose effects / uncertainty: Hypoglycemia is a serious IGF-class concern, but inspected LR3 accounts conflict: one six-week 30–50 mcg/day report kept fasting glucose and A1C in range, while another claimed no symptoms even at 200 mcg fasted. Shaking, sweating, confusion, blurred vision, seizure or loss of consciousness remain emergency symptoms; these anecdotes do not establish safety. forumanecdote
- Never fasted / never careless bedtime: Community hard rules for hypo mitigation; keep fast carbs (glucose tablets, juice) available around doses. forum
- Insulin / insulin-secretagogue combo: Additive glucose crash — widely treated as advanced-only or avoid in unsupervised research-chem settings. forum
- IM technique risk: Nerve/vessel contact risk higher than SubQ; site-enhancement does not cancel systemic effects. forum
- Water / soft fullness / edema: Facial or systemic fullness hard to separate from diet and GH-axis stacks. anecdote
- Joint aches, headache, lethargy, nausea: Minority logs; causality muddy under polypharmacy. forum
- Organ growth / visceral concern: Long or high exposure lore includes kidney/spleen/heart growth risk and irreversible “GH gut”–style abdominal expansion worry — primary argument for short cycles. forum
- Endogenous GH suppression: Exogenous IGF-1 can feedback-suppress pituitary GH — another reason some avoid late-evening dosing. forum
- Desensitization: Continuous multi-week-plus use framed as less efficient over time via receptor downregulation — widely believed lore; gym users rarely assay receptors. forum
- Insulin resistance talk: Progressive glucose-handling worsening on long runs is part of the anti-continuous-use argument. forum
- Source quality: Mislabel, underdosing, contamination, wrong peptide — structural gray-market risk independent of mechanism. forum
- Hypo window 2025–26: Shake/sweat/fog still clusters ~30–90 min post-pin, especially fasted cardio or stacked insulin-sensitizers / GLP-1s that hide hunger cues. forum
- Waist / organ-growth lore: Progressive unexplained abdominal expansion remains the community stop flag for stretching a 4-week block. forum
- Acetic-acid sting ≠ potency: Site burn from acidic diluent is handling talk, not proof the analog is “strong.” forum
- Don’t chase a serum IGF-1 number on LR3: Analog + assay mismatch + GH feedback can make the printout lie either way. Watch glucose and waist. forum
- Increlex-adjacent magnitude (native rhIGF-1, not LR3 trial): FDA program data often summarized as hypo in a large minority (~42% of 71 pediatric subjects in classic labeling summaries), with severe events and rare seizures/LOC — informs pathway risk, not LR3-specific rates. trial
- Injection sites: Pain, redness, swelling, bruising; lipohypertrophy with repeated same-spot use (also noted on mecasermin labels). trial
- Intracranial hypertension class warning: Mecasermin label notes papilledema / intracranial hypertension in a small number of subjects — new severe headache with visual change is a stop-and-evaluate flag in adjacent safety talk. trial
- Lymphoid / tonsillar hypertrophy (adjacent): Documented in rhIGF-1 clinical use; not a common gym talking point but pathway-relevant. trial
- Acromegaloid change (chronic excess IGF/GH axis): Long-term overdose narratives borrow from excess GH/IGF physiology (soft-tissue overgrowth, cardiac risk) — more cautionary physiology than common short-block outcome. trial
- Mitogenic / cancer-pathway caution: IGF1R signaling is growth- and anti-apoptosis–related; active/recent malignancy is a hard community and label-style contraindication; epidemiology links higher circulating IGF-1 to certain cancer risks. trial
- Preclinical tumor model note: IGF-1 LR3 class work has shown support of protein turnover but also increased tumor growth in tumor-bearing rat models in cited papers — pathway concern, not a human incidence rate for short gym cycles. animal
- Pregnancy / diabetes / organ disease: Community and adjacent label logic treat these as avoid/contraindication zones without specialist care. trial
- Tested sport: WADA-prohibited; not “undetectable” in modern anti-doping context. trial
- Not risk-free “research only” word magic: Research-chemical framing does not erase hypo, growth-pathway, or sterility risks. forum
Evidence mix
Mostly community / anecdote tags
Full: every bullet (trial + community). Use Scan for a faster bro-science read.