Muscle · Reference
IGF-1 LR3 Side Effects: Low Blood Sugar, the Cancer Question, and What to Report
This page is a practical reference to what to watch, what to do and who should not take it. What IGF-1 LR3 is, how it differs from native IGF-1 and what research has looked at are in what is IGF-1 LR3.
The side effect that matters most with IGF-1 LR3 is low blood sugar: IGF-1 has insulin-like effects, native IGF-1 caused hypoglycaemia in healthy adults in published work, and IGF-1 LR3 is designed to escape the binding proteins that normally buffer that effect. Shakiness, sweating, sudden hunger, confusion or light-headedness after a dose mean eat something, then contact your care team. The second concern is growth signalling: IGF-1 promotes the growth and survival of cells generally, so a personal or family history of cancer is treated as a reason not to use it. Beyond those, prescribers most often report injection-site redness or soreness and headache. There are no human trials of IGF-1 LR3, so none of this has been measured for the analogue itself.
This page is a practical reference to what to watch, what to do and who should not take it. What IGF-1 LR3 is, how it differs from native IGF-1 and what research has looked at are in what is IGF-1 LR3.
IGF-1 LR3 Side Effects
The short answer
| Side effect | Where the concern comes from | What to do |
|---|---|---|
| Low blood sugar (hypoglycaemia) | Insulin-like effects of IGF-1; seen with native IGF-1 in healthy adults | Know the signs; eat, then call; severe or confused: 911 |
| Growth signalling and cancer risk | IGF-1 promotes cell growth; observational association with several cancers | A personal or family history of cancer rules it out at Pepti |
| Injection-site redness or soreness | Prescriber reports | Rotate sites |
| Headache | Prescriber reports | Report it; headache with visual change needs same-day care |
| Hunger or light-headedness after a dose | Prescriber reports; may be low blood sugar | Treat it as low blood sugar until shown otherwise |
| Lymphoid tissue swelling, raised pressure inside the skull, joint pain | Approved native IGF-1 labelling, mostly in children | Unknown for adults on the analogue; report any of them |
The products this page covers:
| Product | What is in it | Typical printed directions | Price |
|---|---|---|---|
| IGF-1 LR3 | 5 mL multi-dose vial, IGF-1 LR3 200 mcg/mL (1000 mcg per vial) | 0.25 mL (25 units) subcutaneously Monday through Friday nights at bedtime | $259/mo |
| ASCEND Blend | 6 mg CJC-1295, 12 mg ipamorelin, 10 mg tesamorelin and 1 mg IGF-1 LR3 in 5 mL | Printed on the vial | $289/mo |
At 200 mcg/mL, 0.25 mL is 50 mcg of IGF-1 LR3 per dose (arithmetic from the vial strength, on a U-100 insulin syringe), and a vial holds 20 doses, about four weeks of weeknight dosing. Your own directions are set by your physician after reviewing your intake and are printed on the vial. Prices are all-in: medication, physician review, refill management and shipping, with no membership fee. IGF-1 LR3 is compounded by a PCAB-accredited, FDA-registered US 503A pharmacy. Compounded medications are not FDA approved.
IGF-1 LR3 Side Effects
Why IGF-1 LR3 carries sharper cautions than most peptides
Insulin-like growth factor 1 is a 70-amino-acid hormone made mostly by the liver in response to growth hormone. In the blood, more than 99 per cent of it is bound to IGF binding proteins, which extend its life, keep it out of tissue until it is wanted, and buffer the insulin-like effects of the free fraction.
IGF-1 LR3 is a laboratory analogue: the 70 amino acids of IGF-1 plus a 13-amino-acid extension, and one substitution (arginine for glutamate at position 3) that sharply reduces binding to those proteins. More of it stays free and active. That is the whole reason the molecule was made, and it is also the reason the cautions are sharper: the binding proteins are a brake as well as a reservoir, and this analogue is built to bypass them.
| Native IGF-1 in your body | IGF-1 LR3 | |
|---|---|---|
| Bound to binding proteins | More than 99 per cent | Sharply reduced |
| Buffering of insulin-like effects | Yes | Largely bypassed |
| Human trials | Yes, as the approved native drug mecasermin, mostly in children | None |
| Effect on your own growth hormone and IGF-1 | It is the signal the pituitary reads | Suppresses them in animal work while it is given |
None of the trial data behind mecasermin belongs to IGF-1 LR3. Its cautions are the part that does transfer, which is the direction this page carries them.
IGF-1 LR3 Side Effects
Low blood sugar: the first thing to know
Why it happens
IGF-1 and insulin are structurally related, and at high concentrations IGF-1 activates the insulin receptor as well as its own. Either route lowers blood glucose by pushing it into muscle and fat. A 1987 paper in the New England Journal of Medicine reported that recombinant native IGF-1 given to healthy adults produced hypoglycaemia. The approved native product carries a warning for severe hypoglycaemia including seizures, and in its labelling, which pools five studies in 71 children, hypoglycaemia was reported at least once in 42 per cent. The approved native product also advises against driving or strenuous activity for two to three hours after a dose until a tolerated dose is established, and is labelled to be given close to a meal or snack.
The signs and what to do
What you notice What it may be What to do Shakiness, sweating, sudden hunger, light-headedness Low blood sugar Eat or drink something with sugar now, then contact your care team Confusion, unusual behaviour, slurred speech More severe low blood sugar Eat or drink sugar if you can swallow safely; call 911 if it does not resolve quickly Unable to swallow safely, unresponsive, or a seizure Severe low blood sugar Someone with you should call 911 Repeated episodes, even mild ones A pattern your physician needs to know about Message your care team before the next dose Anyone prescribed IGF-1 LR3 is told what low blood sugar feels like, and what to do about it, before the first dose. Your directions on timing and food are the ones to follow; if they are unclear, ask before the first dose rather than after. Never change your own dose.
Who is at higher risk
Insulin and any other glucose-lowering medication are the interactions a physician asks about first. Diabetes, impaired glucose tolerance or a tendency to low blood sugar is raised at intake for the same reason, and IGF-1 LR3 is not prescribed alongside insulin without a specific plan.
IGF-1 LR3 Side Effects
Growth signalling and the cancer question
IGF-1 promotes the growth and survival of cells, not only muscle cells. A 2004 systematic review in the Lancet reported that higher circulating IGF-1 in the general population was associated with a higher risk of prostate cancer, premenopausal breast cancer and colorectal cancer. That is an association in observational data, not a demonstration that IGF-1 causes cancer, and it concerns the native hormone. The approved native product is contraindicated in anyone with a malignancy or a history of one.
The animal work points the same way. A 1995 paper in the Journal of Endocrinology infused LR3 IGF-1 into guinea pigs and reported that organs grew while the animal's own IGF-1, IGF-2 and binding proteins fell, and a 1992 paper in the Journal of Endocrinology reported marked growth of the gut in rats given IGF-1 analogues including LR3. It is a signal that grows whatever tissue it reaches.
The prudent reading is that a personal or family history of cancer is a reason not to use this peptide, and Pepti's intake treats it that way. The broader question is covered in can peptides cause cancer. Long-term safety is not established, and a concern with any growth-promoting signal is exactly the kind that would only show up over years.
IGF-1 LR3 Side Effects
Other side effects
What prescribers report
Effect Detail Injection-site redness or soreness The most common report; rotate sites Headache Reported; a headache with visual change needs same-day care Hunger or light-headedness after a dose Treat as possible low blood sugar Nothing at all Most people report nothing visible in the first week, which is normal What the approved native IGF-1 labelling lists
Beyond low blood sugar, the approved native product's labelling lists swelling of lymphoid tissue, raised pressure inside the skull (headache with visual change), joint pain and injection-site changes, mostly in children. Whether and how often these apply to adults on the analogue is unknown. Report any of them.
Your own axis
IGF-1 is the signal the pituitary reads to decide how much growth hormone to release, so supplying it from outside turns the body's own output down. Animal work describes the body's own IGF-1 and binding proteins being suppressed while the analogue is given and recovering afterwards; there is no human data on this. No withdrawal and no rebound have been reported, because the studies that would report them have not been done.
Quality
The FDA has raised a general concern about immunogenicity with injectable compounded peptides. A 2010 paper in Growth Hormone & IGF Research analysed a black-market product sold as LR3 and found a research-grade version with a purification tag still attached. Where the vial comes from matters; Pepti publishes lot test results at /quality/lab-results.
IGF-1 LR3 Side Effects
Serious reactions: what needs emergency care
| Symptom | What it may be | What to do |
|---|---|---|
| Confusion, a seizure, or being unable to eat or drink safely | Severe low blood sugar | Call 911 |
| Swelling of the face, lips or throat, widespread hives, trouble breathing | Serious allergic reaction | Call 911 first, then tell your care team |
| A severe headache with visual change | Possible raised pressure inside the skull | Same-day urgent care; call 911 if severe or with confusion |
| You think you injected far more than your directions | Possible overdose, with a high risk of low blood sugar | Eat something with sugar, call Poison Control at 1-800-222-1222, and message your care team; call 911 for any confusion or drowsiness |
| An injection site that is hot, spreading or worse after 48 hours | Possible infection rather than irritation | Message your care team the same day |
| A reaction that is severe or spreading | Not an expected effect | Stop and contact your care team |
IGF-1 LR3 Side Effects
Injection-site reactions and storage
IGF-1 LR3 is injected under the skin, into the fat layer, usually in the abdomen or thigh, rotating sites so the same spot is not used repeatedly. A small lump that appears as you inject and softens over a day or two is fluid in the tissue; one that appears days later and is warm or spreading needs a same-day message. Technique is in how to inject peptides safely.
It ships refrigerated with ice packs, with sterile syringes and alcohol prep pads. Keep it out of the freezer and out of light. Beyond-use dating runs from first puncture and is on the label.
IGF-1 LR3 Side Effects
When to message your care team
- any episode of shakiness, sweating, sudden hunger or light-headedness after a dose, even if it passed
- a headache that persists, or any change in vision
- joint pain or swelling that is new
- a new lump anywhere, a changing mole, or unexplained weight loss
- you are diagnosed with diabetes or any cancer
- you start any new medication, especially anything that lowers blood glucose
There is no established interaction list for IGF-1 LR3, because the trials that would produce one have not been run. That is why the intake asks for every medication you take.
IGF-1 LR3 Side Effects
Who should not take IGF-1 LR3
| Situation | Status |
|---|---|
| Personal or family history of cancer | Treated as a reason not to prescribe |
| Diabetes, impaired glucose tolerance or a tendency to low blood sugar | Raised at intake; usually a reason not to prescribe |
| Taking insulin or another glucose-lowering medication | Not prescribed without a specific plan |
| Diagnosed low IGF-1 or growth hormone deficiency | An endocrinologist's conversation; IGF-1 LR3 is not a treatment for it |
| Pregnancy or breastfeeding | Not used; safety data is absent |
| Tested athletes | IGF-1 and its analogues are prohibited at all times under the WADA code |
| Under 18 | Pepti prescribes to adults only |
Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account.
IGF-1 LR3 Side Effects
IGF-1 LR3 vs growth hormone secretagogue side effects
Sermorelin, CJC-1295 / Ipamorelin and tesamorelin act upstream at the pituitary, so your own gland releases growth hormone in pulses and rising IGF-1 feeds back to slow them. Their typical side effects are the growth-hormone-axis cluster: fluid retention, joint ache and tingling hands when the dose is above what you need. IGF-1 LR3 delivers the end signal directly and bypasses that feedback, which is why its cautions, low blood sugar and the cancer question, are sharper. In the ASCEND Blend the IGF-1 LR3 cautions apply in full. The wider category is in peptides for muscle growth and recovery.
IGF-1 LR3 Side Effects
What the evidence shows, honestly
There are no randomised controlled trials of IGF-1 LR3 in humans and essentially no published human clinical studies of it at all. The side-effect picture on this page is assembled from three places: what native IGF-1 did in people (low blood sugar), what the approved native product's labelling warns about (severe hypoglycaemia, a malignancy contraindication and a list of mostly paediatric effects), and what prescribers report. Nothing shows the analogue is exempt from any of the native hormone's cautions, and its design removes the buffer that softens them. Any source describing IGF-1 LR3 as free of side effects is not describing the evidence. The general picture is in peptide side effects: what to watch for.
IGF-1 LR3 Side Effects
Where to get IGF-1 LR3 prescribed
IGF-1 LR3 cannot be bought legitimately without a prescription. Products sold "for research use only" have no accountable pharmacy behind their identity, purity, sterility or concentration, and the black-market LR3 analysed in 2010 still carried a manufacturing tag. The prescription route:
- Complete a free online intake covering your history, medications, cancer and family history, blood sugar and what you want help with.
- A physician licensed in your state reviews it, usually within 24 hours.
- If it is appropriate, a PCAB-accredited, FDA-registered US 503A compounding pharmacy prepares it to that prescription. Lot test results are published at /quality/lab-results.
- It ships refrigerated with ice packs, with sterile syringes and alcohol prep pads, and your directions printed on the vial.
- Your care team stays reachable for side effects and questions. Refills run every 28 days, one vial per fill.
Pepti is cash-pay and does not bill insurance, and prescribes IGF-1 LR3 in every state except Oklahoma, plus DC The step-by-step page is how to get IGF-1 LR3 prescribed online.
References
What this is based on.
References
- Philippou A, Maridaki M, Halapas A et al.. The role of the insulin-like growth factor 1 (IGF-1) in skeletal muscle physiology · In Vivo (2007) · PMID 17354613
- Francis GL, Ross M, Ballard FJ et al.. Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency · J Mol Endocrinol (1992) · PMID 1378742
- Tomas FM, Knowles SE, Owens PC et al.. Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats · Biochem J (1992) · PMID 1371669
- Read LC, Tomas FM, Howarth GS et al.. Insulin-like growth factor-I and its N-terminal modified analogues induce marked gut growth in dexamethasone-treated rats · J Endocrinol (1992) · PMID 1613443
- Conlon MA, Tomas FM, Owens PC et al.. Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig · J Endocrinol (1995) · PMID 7561636
- Guler HP, Zapf J, Froesch ER. Short-term metabolic effects of recombinant human insulin-like growth factor I in healthy adults · N Engl J Med (1987) · PMID 3299085
- Chernausek SD, Backeljauw PF, Frane J et al.. Long-term treatment with recombinant insulin-like growth factor (IGF)-I in children with severe IGF-I deficiency due to growth hormone insensitivity · J Clin Endocrinol Metab (2007) · PMID 17192294
- Renehan AG, Zwahlen M, Minder C et al.. Insulin-like growth factor (IGF)-I, IGF binding protein-3, and cancer risk: systematic review and meta-regression analysis · Lancet (2004) · PMID 15110491
- Adams GR, McCue SA. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats · J Appl Physiol (1998) · PMID 9572822
- Musarò A, McCullagh K, Paul A et al.. Localized Igf-1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle · Nat Genet (2001) · PMID 11175789
- Barton-Davis ER, Shoturma DI, Musaro A et al.. Viral mediated expression of insulin-like growth factor I blocks the aging-related loss of skeletal muscle function · Proc Natl Acad Sci U S A (1998) · PMID 9861016
- Allard JB, Duan C. IGF-Binding Proteins: Why Do They Exist and Why Are There So Many? · Front Endocrinol (Lausanne) (2018) · PMID 29686648
Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.
Common questions
IGF-1 LR3 Side Effects, answered.
The ones that matter are low blood sugar and the theoretical growth-signalling concern. Beyond those, prescribers most often report injection-site redness or soreness, headache, and hunger or light-headedness after a dose. The approved native IGF-1 labelling also lists lymphoid tissue swelling, raised pressure inside the skull and joint pain, mostly in children.
It can. IGF-1 has insulin-like effects, native IGF-1 produced hypoglycaemia in healthy adults in a 1987 study, and the approved native product warns of severe hypoglycaemia including seizures. IGF-1 LR3 is designed to escape the binding proteins that buffer that effect.
Shakiness, sweating, sudden hunger, confusion or light-headedness after a dose. Eat or drink something with sugar, then contact your care team. Confusion that does not resolve quickly, a seizure, or being unable to swallow safely needs 911.
Nobody has shown that it does, and nobody has shown that it does not. Higher circulating IGF-1 has been associated with prostate, premenopausal breast and colorectal cancer in observational research, and the approved native product is contraindicated in malignancy. A personal or family history of cancer is treated as a reason not to prescribe it.
Headache is reported by prescribers. A headache with visual change needs same-day care, because raised pressure inside the skull is listed on the approved native IGF-1 labelling.
Joint pain is listed on the approved native IGF-1 labelling, mostly in children; whether it applies to adults on the analogue is unknown. Report new joint pain or swelling.
In animal work it lowers the body's own growth hormone and IGF-1 output while it is given, with recovery afterwards. There is no human data on how long that lasts.
Diabetes, impaired glucose tolerance and any glucose-lowering medication are raised at intake, and IGF-1 LR3 is not prescribed alongside insulin without a specific plan. For most people with diabetes it is not the right peptide.
Long-term safety is not established. There are no human trials, and a concern with any growth-promoting signal is the kind that would only show up over years.
IGF-1 and its analogues are prohibited at all times under the WADA code, and anti-doping laboratories have published methods for detecting LR3. See do peptides show up on a drug test.
Eat or drink something with sugar, call Poison Control at 1-800-222-1222, and message your care team. Call 911 for any confusion, drowsiness, a seizure, or inability to swallow safely. The free assessment goes to a physician licensed in your state. A consultation does not guarantee a prescription.
Next step
See what a physician recommends for you.
A licensed physician in your state reviews your intake and decides what is appropriate. A consultation does not guarantee a prescription.