Can peptides cause cancer?

What the label, human studies or user reports say about cancer for each of 68 compounds, grouped by where the answer comes from.

Compounds: 68
From labels: 16
From human studies: 3
Not reported when studied: 4
No human data: 9

Each answer says whether cancer was reported, and how often where that’s known. “Not reported” means the label or trials didn’t list it, not that it can’t happen. Talk to a doctor or pharmacist about any symptom that worries you.

Why each concern arises, grouped by how the compounds work: peptides and cancer.

From a product label 16

What the prescribing information says, with rates against placebo where the label gives them.

CerebrolysinApproved drug: LabelThe EU label says standard animal studies, including of cancer potential, show no special risk; Romania’s label adds that clinical experience hasn’t shown cancer-causing effects.
ExenatideApproved drug: LabelThe twice-daily pen has no boxed warning, though benign thyroid tumors rose in rats; the weekly form had one. In EXSCEL, pancreatic and medullary thyroid cancers didn’t differ from placebo.
hCGApproved drug: LabelRuled out with prostate, breast and other hormone-sensitive tumors. Testicular tumors were reported now and then in young men treated for infertility; no causal link was established.
L-CarnitineApproved drug: LabelThe label says no long-term animal studies of cancer risk have been done; lab tests in bacteria and yeast found no gene damage.
LiraglutideApproved drug: LabelCaused thyroid tumors in rodents; human risk is unknown (boxed warning). In Saxenda’s trials, breast cancer hit 0.7% of women vs 0.2% on placebo, too few cases to judge cause.
OrforglipronApproved drug: LabelHas the class boxed warning for thyroid tumors; it can’t act in rodents, which got none. Ruled out with a personal or family history of medullary thyroid cancer or MEN 2.
OxytocinApproved drug: LabelThe US label says no animal or human studies of cancer risk exist; long-term nasal use hasn’t been studied for it.
PT-141Approved drug: LabelTwo-year rat and mouse studies found no rise in tumors, and gene-damage tests were negative. The label doesn’t address moles or skin cancer.
SemaglutideApproved drug: LabelCaused thyroid tumors in rodents; human risk is unknown (boxed warning). Ruled out with a personal or family history of medullary thyroid cancer or MEN 2, an inherited tumor syndrome.
SS-31Approved drug: LabelUnknown: carcinogenicity studies haven’t been done. It caused no DNA damage in lab and rat tests, the label says.
TesamorelinApproved drug: LabelRuled out with active cancer because it raises growth hormone, a known growth factor. The label urges care given HIV’s higher cancer risk; lifetime animal cancer studies weren’t done.
TirzepatideApproved drug: LabelCaused thyroid tumors in rats; human risk is unknown (boxed warning). Ruled out with a personal or family history of medullary thyroid cancer or MEN 2, an inherited tumor syndrome.
TriptorelinApproved drug: LabelIn prostate cancer, the early testosterone surge can worsen the disease. Rats given it for 13–19 months developed more pituitary and other tumors; mice didn’t, and DNA-damage tests were negative.
GonadorelinApproved drug: LabelNo cancer risk is listed. The UK label advises against use with a pituitary tumor because bleeding into the gland (pituitary apoplexy) can occur.
Melanotan 1Approved drug: LabelNo cancer studies; DNA-damage tests were negative (US label). Labels advise twice-yearly skin checks. Melanomas in existing moles have been reported with unlicensed melanotan injections.
ThymalinApproved drug: LabelNot listed as a risk in the Russian label, which approves it for people with cancer after chemotherapy or radiotherapy, to restore immunity and blood cell production.

From human studies 3

What published trials and case reports found.

AOD9604Human studies: TrialIn a 12-week trial, 4 people on it had cancers reported, including melanoma and breast cancer; investigators called them unrelated, and FDA said the data are too thin to judge.
LL-37Human studies: TrialThe 3-patient melanoma injection study recorded squamous cell skin cancer in one; a case report describes cancer-like skin growths that cleared after stopping. FDA cites lab findings of tumor promotion.
Melanotan 2Human studies: TrialNo controlled data. Several case reports describe melanomas arising in moles during or after melanotan use, and FDA cites them; whether it causes melanoma is unproven.

A precaution, not measured 33

A concern that follows from how it works or from a related drug.

MazdutideApproved drug: PrecautionA 248-person phase 2 trial saw no thyroid tumors and no calcitonin, a thyroid tumor marker, of 20 ng/L or more. Related drugs caused thyroid tumors in rodents.
CagrilintideHuman studies: PrecautionUnknown: trials have lasted up to 68 weeks, too short to judge, and no animal cancer studies are published. Semaglutide’s thyroid tumor warning would apply to CagriSema.
DihexaHuman studies: PrecautionHGF and its receptor c-Met drive the growth of many cancers, and dihexa is claimed to boost that signal. No cancer study of dihexa or its prodrug exists.
BPC-157Preclinical: PrecautionFDA found no cancer studies; lab tests showed no DNA damage. It promotes blood vessel growth in animals, which tumors also use, so cancer risk is a theoretical concern.
CartalaxPreclinical: PrecautionUnknown. In cell studies it raised cell-division markers and lowered p53 and other brake proteins on cell growth. No study has tested what it does in cancer.
EpithalonPreclinical: PrecautionUnresolved: it switches on telomerase, which FDA says could raise cancer risk with continuous use; intermittent mouse studies found fewer tumors but were too limited to judge.
FOXO4-DRIPreclinical: PrecautionUnknown. In senescent cells it pushes p53, the body’s main tumor-suppressor protein, out of the nucleus. No long-term study has looked at cancer risk, in animals or people.
HumaninPreclinical: PrecautionUnknown in people. In mice with an aggressive (triple-negative) breast cancer, humanin shielded tumor cells from chemotherapy and sped growth and spread; its cancer role is unresolved.
PinealonPreclinical: PrecautionUnknown. In a cell study its developers reported that it activates processes that make cells multiply and alters the cell cycle. No study has tested effects on tumors.
GHRP-2Approved drug: PrecautionNo study has looked at cancer. It raises growth hormone, and with continuous dosing IGF-1, both of which promote cell growth, so risk with repeated use is a theoretical concern.
GlutathioneApproved drug: PrecautionNo cancer signal in trials; a 185-person chemotherapy trial found no change in time to progression. Tumors use glutathione to resist treatment, a theoretical concern with extra doses.
VIPApproved drug: PrecautionNo human data. VIP roughly doubled colony growth of a lung cancer cell line, and blocking its receptor slowed lung tumors in mice; kidney cancer cells grew slower with it.
ARA-290Human studies: PrecautionNo cancers were reported in trials lasting 28 days to 12 weeks, but it promotes tissue repair and blood vessel growth, so long-term risk is unknown. Trials excluded recent cancer.
CJC-1295 with DACHuman studies: PrecautionNo cancer studies exist. It keeps GH and IGF-1 raised for over a week; FDA cites pituitary tumors in mice making excess GHRH and DNA damage in mouse pituitary cells.
GHK-CuHuman studies: PrecautionNo cancer studies exist. It encouraged blood vessel growth in animal studies, which tumors also use, so injected use raises a theoretical concern.
GHRP-6Human studies: PrecautionNo study has looked at cancer. It raises growth hormone and IGF-1, which promote cell growth, so risk with repeated use is a theoretical concern.
HexarelinHuman studies: PrecautionNo study has looked at cancer. It raises growth hormone, which promotes cell growth, so risk with repeated use is a theoretical concern.
IpamorelinHuman studies: PrecautionNo cancer studies exist. It raises GH and then IGF-1, and FDA says the tumor risk on growth hormone labels may also apply to drugs that raise GH.
MK-677Human studies: PrecautionNo trial was designed to look at cancer, and FDA found no animal cancer studies. It keeps IGF-1 raised, and higher IGF-1 is linked with cancer risk.
NAD+Human studies: PrecautionNo human data. Some cancers make extra NAD+-producing enzyme, and blockers of it have been tested as cancer drugs, so boosting NAD+ with an existing cancer is a theoretical concern.
RetatrutideHuman studies: PrecautionNo cancer signal has been reported. Related drugs caused thyroid C-cell tumors in rats, so trials excluded anyone with personal or family history of medullary thyroid cancer or MEN 2.
SermorelinHuman studies: PrecautionNo cancer studies: long-term animal tests weren’t done, and tests showed no genetic damage. It raises GH and IGF-1, which promote cell growth, so active cancer is a theoretical concern.
SurvodutideHuman studies: PrecautionNo cancer signal has been reported. Related drugs caused thyroid C-cell tumors in rodents, so trials excluded anyone with personal or family history of medullary thyroid cancer or MEN 2.
TesofensineHuman studies: PrecautionNo cancer data: published trials lasted up to 48 weeks and excluded people with recent cancer, and no animal cancer studies have been published.
Thymosin Beta-4Human studies: PrecautionNo cancers were reported in trials of up to 12 weeks, but it drives cell migration and new blood vessels and is raised in some tumors; long-term risk is unknown.
AHK-CuPreclinical: PrecautionNo cancer studies exist. In lab tests it made hair-follicle cells multiply and die less, growth effects that leave long-term cancer risk an untested, theoretical question.
CJC-1295 (no DAC)Preclinical: PrecautionNo cancer studies exist. It is designed to raise GH and IGF-1, which drive cell growth, and mice making excess GHRH develop pituitary tumors (FDA).
Follistatin-344Preclinical: PrecautionNo cancer studies. It blocks activin and myostatin, signals that hold tissue growth back, so cancer risk is a theoretical concern. Gene therapy adds its own long-term unknowns.
IGF-1 DESPreclinical: PrecautionNo cancer studies. It acts on the IGF-1 receptor, which drives cell growth. Mecasermin is ruled out in children with cancer, and cancers have been reported after its use.
IGF-1 LR3Preclinical: PrecautionNo cancer studies. It acts on the IGF-1 receptor, which drives cell growth. Mecasermin is ruled out in children with cancer, and cancers have been reported after its use.
PEG-MGFPreclinical: PrecautionNo data on PEG-MGF. Plain MGF made prostate, breast and bone cancer cells multiply in lab studies, so a longer-acting form raises a theoretical concern.
SLU-PP-332Preclinical: PrecautionNo cancer data. ERRα, the receptor it activates most, has been studied as a target to block in breast and ovarian cancer; what long-term activation does is unknown.
TB-500Preclinical: PrecautionNo cancer studies exist. Its parent protein drives cell movement and new blood vessel growth, and high levels appear in some tumors, so cancer risk is a theoretical concern.

Seen only in animals 3

Animal findings don’t show what happens in people.

KPVPreclinical: AnimalFDA found no cancer studies. In mice prone to colitis-linked bowel tumors, KPV reduced tumors, so no animal signal points the other way.
DSIPApproved drug: AnimalNo human data. In mice given monthly Deltaran courses for life, spontaneous tumors were 2.6 times rarer (2003), an animal result that says nothing about risk in people.
MGFPreclinical: AnimalNo human data. In lab studies it made prostate, breast and bone cancer cells multiply; in mice, prostate cells engineered to make it grew faster or spread more.

Studied in people, not reported 4

Labels or trials covered enough people and didn’t report it. It can still happen.

Thymosin Alpha-1Approved drug: Not reportedNot reported as a side effect in trials lasting up to a year, several of them in people with cancer. FDA found no animal studies of cancer risk.
ArgirelineHuman studies: Not reportedNo signal in the small skin trials, but no cancer studies exist; a bacterial gene-mutation test was negative, and lab tests found almost none reaches deeper skin.
LarazotideHuman studies: Not reportedNot reported in trials lasting up to 12 weeks, which are too short to judge cancer risk; no long-term study exists.
MatrixylHuman studies: Not reportedNot reported in trials up to 12 weeks, and no cancer studies exist; a 2024 safety review noted negative gene-damage tests and little absorption through skin.

No human safety data 9

No one has been given it in a published study, so it can’t be ruled in or out.

Kisspeptin-10Human studies: No dataFDA found no cancer or gene-damage studies. Kisspeptin was first identified as the product of a gene that curbs cancer spread in lab models.
MOTS-cPreclinical: No dataUnknown: FDA’s 2026 review found no cancer, DNA-damage or repeat-dose toxicity studies in animals, and no human data.
SelankApproved drug: No dataNo data. No long-term human study exists, and the Russian label doesn’t address cancer.
SemaxApproved drug: No dataNo cancer data in people and no long-term studies. The Russian labels say lab tests found no mutagenic (DNA-damaging) effects.
SNAP-8Human studies: No dataNo human or animal cancer data; the only human studies lasted 4–12 weeks and tested mixes.
5-Amino-1MQPreclinical: No dataNo human data, and no long-term animal study has looked at cancer risk.
AdamaxPreclinical: No dataNo data; Adamax has never been studied in animals or people.
HGH Fragment 176-191Preclinical: No dataNo cancer data for this peptide. In a 12-week trial of AOD9604, a related peptide, 4 people had cancers reported; investigators called them unrelated.
PE-22-28Preclinical: No dataNo data: no cancer or long-term animal safety studies have been published.

Sources

Each answer comes from the compound’s own page, under “Can it cause …?”, where its sources are listed.

By Vial Guide editorsLast reviewed October 7, 2026

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