"Peptides and cancer" is two questions run together. One is whether peptide drugs can cause cancer. The other is whether a specific peptide people are buying — tesamorelin, BPC-157, IGF-1 — does. The record answers the first for a handful of approved drugs and is silent on the second for nearly everything sold as a research chemical.
This page sets out what the FDA labels say, what was measured in people, and where nothing has been measured. GLP-1 drugs are not covered here: their thyroid-tumour warning and cancer record are on GLP1 Ledger's GLP-1 and cancer page. Nothing on this page is medical advice; anyone with a cancer history or a specific concern should take it to their oncologist or prescriber.
The five approved peptides whose labels warn about cancer
Not every approved peptide label was read for this page; the five below are the peptides people most often ask about whose current labels name cancer in their warnings. Each label was read through openFDA on 7 October 2026.
| Drug (peptide) | Why the label warns | What the label says | Kind of evidence |
|---|---|---|---|
| Tesamorelin — EGRIFTA WR / SV (44-amino-acid GHRH analogue) | Raises GH and IGF-1, "a growth factor" | Contraindicated in active malignancy; pre-existing cancer "should be inactive and its treatment complete"; "discontinue … if there is any evidence of recurrent malignancy"; consider the "increased background risk of malignancies in HIV-positive patients" | Mechanism — no trial signal reported |
| Mecasermin — INCRELEX (recombinant IGF-1, 70 amino acids) | Is itself a growth factor | Contraindicated in children with "malignant neoplasia or a history of malignancy"; "several cases of malignant neoplasia have been observed in pediatric patients"; tumours "observed also more frequently" at higher than recommended doses or with IGF-1 above the normal range | Post-marketing reports, mostly in children with cancer-predisposing conditions |
| Teriparatide — FORTEO (34-amino-acid PTH fragment) | Bone tumours in rats | Osteosarcoma increased "in male and female rats"; "reported in patients … in the post marketing setting; however, an increased risk … has not been observed in observational studies in humans"; avoid in people at higher baseline risk | Animal finding plus human observational data |
| Abaloparatide — TYMLOS (34-amino-acid PTHrP analogue) | Bone tumours in rats | Avoid in people at increased osteosarcoma risk (open growth plates, Paget's disease, bone metastases, prior skeletal radiation, hereditary predisposition) | Animal finding |
| Calcitonin salmon — MIACALCIN (32 amino acids) | A malignancy excess in human trials | In a meta-analysis of 21 randomised trials, malignancies in 4.1% of calcitonin-treated patients vs 2.9% on placebo; an increased risk with long-term injection "is not possible to exclude" | Human randomised-trial data |
Calcitonin is the only row built on a human trial signal. The others are precautions: a mechanism (growth factors), or an animal finding that human data have so far not confirmed. That difference is the most important thing on this page, because it is the difference between "this drug caused cancers in people" and "this drug acts on a pathway cancers also use."
Teriparatide: a warning that was narrowed by evidence
Teriparatide is the clearest case of a peptide cancer warning changing as human data arrived. It was approved with a boxed warning about osteosarcoma in rats and a two-year lifetime limit. The current label carries no boxed warning; it keeps the rat finding, adds that observational studies in humans have not shown an increased risk, and makes use beyond two years something that "should only be considered" if fracture risk stays high. What the label still calls limited is the data beyond two years. The dosing record is on our teriparatide dosage page.
Growth-hormone peptides: the IGF-1 question
The GH-releasing peptides — tesamorelin, sermorelin, ipamorelin, CJC-1295, MK-677 (not a peptide, but sold beside them) — all raise IGF-1. IGF-1 helps cells grow and survive, which is why it is a cancer question at all.
What the record holds:
- Tesamorelin has the only label among them, and it contraindicates active cancer without reporting a trial signal. The label's own reasoning is that GH is "a known growth factor". Its trials were in people with HIV, who have a higher background cancer rate, so the label asks prescribers to weigh that. Searched as "does tesamorelin cause cancer" about 720 times a month: the label's answer is that no signal was reported and the drug is avoided where cancer is active. More of its record is on our tesamorelin side effects page.
- Mecasermin shows what happens at the end of the pathway — IGF-1 itself — and its label is the only one that ties tumours to dose: more often above the recommended dose or above the normal IGF-1 range. That observation is the closest thing to a dose-response in this family, and it comes from post-marketing reports, not a controlled trial.
- IGF-1 LR3, the engineered research version, has never been studied in people; what the mecasermin label does and does not say about it is on our IGF-1 LR3 side effects page.
- Sermorelin, ipamorelin and CJC-1295 have no cancer outcome in any trial found; their trials were weeks to months long and enrolled tens of people. The discontinued sermorelin product GEREF was withdrawn for reasons FDA found were not safety or effectiveness.
The shared limitation: no trial of any GH-releasing peptide was long enough, or large enough, to detect a change in cancer rates. Cancer takes years to show; these trials ran for weeks.
BPC-157: the angiogenesis question, and what was tested
"Does BPC-157 cause cancer" is asked about 260 times a month. The worry has a specific source. BPC-157's healing effects in animal studies are attributed partly to angiogenesis — new blood-vessel growth — and tumours need new blood vessels to grow.
The laboratory evidence for the mechanism is real. In Hsieh et al., J Mol Med 2017, BPC-157 increased vessel density in a chick-embryo membrane assay and in endothelial-cell tube formation, and raised expression and activation of VEGFR2, the main receptor for the vessel-growth signal VEGF. A 2026 clinical review in Missouri Medicine (Moiz et al., PMID 42757290) lists "pathological angiogenesis" and "carcinogenesis" among the potential risks of unregulated peptides including BPC-157 — as potential risks, not observed ones.
What has not been done:
- No human study. ClinicalTrials.gov returned four BPC-157 registrations on 7 October 2026 (rotator-cuff surgery recovery, hamstring strain, a gummy product, and a 2015 safety and pharmacokinetics study with unknown status). None measures cancer, and none has posted results.
- No published long-term carcinogenicity study — the two-year rodent study that approved drugs go through — was found in PubMed. A search for BPC-157 with tumour, cancer or carcinogen terms in title or abstract returned 10 records on 7 October 2026; they are reviews and organ-protection studies from the group that discovered the peptide, including one proposing BPC-157 against cancer cachexia. None is a test of whether it causes or accelerates cancer.
So the honest position is that BPC-157's mechanism makes the question reasonable and the record does not answer it. The same is true of TB-500, where the worry rests on studies finding higher levels of the body's own thymosin beta-4 in some tumours; that record is on our TB-500 side effects page. The wider safety picture for unapproved peptides is on our are peptides safe page.
Melanotan and skin cancer
Melanotan II, sold as a tanning peptide, sits in a separate literature: case reports of new or changing moles and melanoma in people using it. Case reports cannot show cause, and no controlled study exists. PeptideGlowJournal's melanotan side effects page collects those reports and regulator warnings with dates.
Peptides used against cancer
Peptide drugs are also cancer treatments. Leuprolide, goserelin and degarelix are approved for prostate cancer, and octreotide for hormone-secreting tumours; they are on our FDA-approved peptides census. This is worth stating because "peptides fight cancer" appears in research-peptide marketing as if it transferred to unrelated molecules. It does not: each of those drugs has its own receptor, its own trials and its own label.
What is not established
- Whether any GH-releasing peptide changes cancer risk over years of use. No trial was long enough.
- Whether BPC-157, TB-500, MOTS-c, KPV or any other research peptide causes, promotes or prevents cancer in people. Not studied.
- Whether research-market products, whose identity and purity are often unverified, carry risks the pure molecule would not. Our peptide testing page explains what a certificate does and does not show.
- Whether people with a past cancer can use any unapproved peptide safely. No study enrolled them; the approved growth-factor labels exclude or restrict them.
Sources and dates
- EGRIFTA WR and EGRIFTA SV (tesamorelin) prescribing information, Theratechnologies, effective 2026-07-29 (set IDs 839334d3… and 3d783378…), via openFDA, sections 4 and 5.1. Read 2026-10-07.
- INCRELEX (mecasermin) prescribing information, effective 2026-05-18 (Eton) and 2025-08-05 (Ipsen), via openFDA, sections 4 and 5.7. Read 2026-10-07.
- FORTEO (teriparatide) prescribing information, Eli Lilly, effective 2026-08-03, via openFDA, section 5.2; no boxed warning in the current label. Read 2026-10-07.
- TYMLOS (abaloparatide) prescribing information, Radius Health, effective 2026-08-11, via openFDA, section 5.2; no boxed warning in the current label. Read 2026-10-07.
- MIACALCIN (calcitonin salmon) injection prescribing information, Mylan Institutional, effective 2024-09-15, via openFDA, section 5.3. Read 2026-10-07.
- Hsieh MJ et al. Therapeutic potential of pro-angiogenic BPC157 is associated with VEGFR2 activation and up-regulation. J Mol Med 2017;95(3):323–33. PMID 27847966. Read 2026-10-07.
- Moiz A, O'Keefe EL, O'Keefe JH. Dangers of injectable peptides and other unregulated "biohacking" drugs. Mo Med 2026;123(4):337–43. PMID 42757290. Read 2026-10-07.
- ClinicalTrials.gov API v2, intervention "BPC-157", 4 records, queried 2026-10-07. PubMed: BPC-157 AND (tumor[tiab] OR cancer[tiab] OR carcinogen*[tiab]), 10 records, queried 2026-10-07.