Contraindicated Conditions

What a contraindication means

A contraindication is a condition in which a drug's label says the drug is not to be used, because the expected harm outweighs any benefit. Labels and clinicians usually sort them into two kinds. An absolute contraindication rules the drug out entirely in that situation; pregnancy on the tesamorelin label is one example. A relative contraindication means the risk is high enough that a clinician weighs it against the expected benefit, often with extra monitoring.

U.S. prescribing information puts these in predictable places. Absolute contraindications sit in section 4, titled "Contraindications." Relative concerns usually appear in section 5, "Warnings and Precautions," and the most serious ones can also appear as a boxed warning at the top of the label.

That split matters for this page. Very few research peptides have a section 4 at all, so most of what gets called a "contraindication" online is an inference. The sections below keep the two apart.

Where the lists come from

For an approved drug, the FDA-approved label is the primary source. It draws on the sponsor's trials and animal toxicology, plus reports collected after approval. Labels get revised, so the versions described here are the ones posted on DailyMed as of October 2026.

Peptides sold for research use only have no label. Most compounds discussed here (BPC-157 and TB-500 among them) have never gone through the trials a label is built from. Any contraindication list for them was put together by whoever wrote it (often a vendor or a forum writer), usually in one of two ways: borrowing from an approved relative that acts on the same pathway, or reasoning from mechanism ("this compound promotes blood vessel growth in rodents, so it may be a poor fit for someone with a tumor"). Both are sensible starting points. Neither has been tested for the specific compound.

What approved labels say

The table lists section 4 contraindications from labels of approved drugs related to compounds on this site. Hypersensitivity appears on nearly every label and is left out unless it's the only entry.

Growth hormone pathway

The Egrifta WR label explains its malignancy contraindication directly: tesamorelin releases the body's own growth hormone, which the label calls "a known growth factor," and it states that any preexisting malignancy is expected to be inactive, with treatment complete, before therapy starts. Pregnancy is listed because reducing visceral fat offers no benefit during pregnancy and could harm the fetus. The hypothalamic-pituitary item covers people whose pituitary signaling has been disrupted (the label names pituitary surgery and head irradiation among the causes), since a releasing hormone needs a working pituitary to act on.

The somatropin label adds acute critical illness, meaning complications after major surgery or trauma and acute respiratory failure. It also lists diabetic retinopathy. In the warnings section, both labels flag glucose: Egrifta WR says glucose intolerance or diabetes may develop and calls for checking glucose before and during treatment, and Genotropin says impaired glucose tolerance may be unmasked.

Readers interested in ipamorelin or MK-677 often borrow these lists. The logic holds up in part, because the downstream signal (growth hormone, then IGF-1) is the same. The size of the rise differs by compound. None of these research compounds has been studied in people with these conditions.

Incretins

Semaglutide and tirzepatide carry a boxed warning for thyroid C-cell tumors. In rodents, both drugs caused dose-dependent C-cell tumors at clinically relevant exposures, and both labels say it's unknown whether this happens in humans. A personal or family history of MTC or MEN 2 is still a listed contraindication. The warnings sections also cover hypoglycemia when these drugs are combined with insulin or a sulfonylurea, and diabetic retinopathy complications in people with type 2 diabetes.

Gray-market vials sold as semaglutide or tirzepatide claim to contain the same molecules, so the label reasoning applies if the contents match the claim. Retatrutide has no label as of October 2026. Applying the GLP-1 class warnings to it is an inference, though a common one, since it also activates the GLP-1 receptor.

Melanocortins and mitochondrial peptides

Vyleesi's contraindication follows from a measured effect. The label describes a transient rise in blood pressure and drop in heart rate after each dose, usually resolving within 12 hours. Melanotan II acts on the same receptor family more broadly and has no label, so any blood pressure caution for it is borrowed from bremelanotide.

Forzinity, approved in 2025 for Barth syndrome, lists only serious hypersensitivity. A short section 4 doesn't mean a drug is safe in every condition. Barth syndrome is rare and the approval was an accelerated one, so the label rests on data from a small number of patients.

Research peptides without a label

For BPC-157 and similar compounds such as MOTS-c, no regulator has set any contraindications. What circulates online falls into two groups.

The first is mechanism-based. Rat and cell-culture studies link BPC-157 to new blood vessel growth (angiogenesis), and thymosin beta-4, the parent of TB-500, is involved in cell migration. Writers then reason that someone with a tumor might want to avoid them. That concern is plausible. It has not been measured in people.

The second comes from missing data. No research peptide has reproductive safety studies. That's why pregnancy and breastfeeding appear on nearly every informal list by default. The absence of evidence is the reason, not a known harm.

The label of the nearest approved relative is an obvious reference point when a clinician is involved. How strictly to apply it to an unapproved compound is a judgment made for an individual, not a rule this site can set.

The three conditions covered in depth

Three conditions come up more than any others, and each has its own page.

• Cancer history. Active malignancy is a section 4 contraindication for both tesamorelin and somatropin, and the concern centers on IGF-1 as a growth signal. The cancer history page covers remission and family history in more depth.
• Diabetes. Growth hormone raises insulin resistance, while GLP-1 drugs lower glucose, so the two drug families push in opposite directions. The diabetes page looks at type 1 and type 2 diabetes separately.
• Pregnancy. Tesamorelin lists pregnancy outright, and the weight-loss labels note that weight loss offers no benefit during pregnancy. The pregnancy page covers planning and breastfeeding, where research peptides have no data at all.

How this connects to monitoring

Several of these label entries come paired with a lab test: glucose for the growth hormone drugs, and IGF-1 for tesamorelin. The blood work schedule describes which tests trials and labels have used. Broader practices around supervision and adverse events are covered in the safety protocols overview, and the symptoms labels and case reports describe are grouped by drug class under warning signs.

Whether a condition rules out a compound for a particular person is a clinician's decision. Labels describe populations; a clinician weighs one person's history and other medicines.

What we still don't know

• Whether growth hormone secretagogues carry the same malignancy or retinopathy risk as somatropin. No study has compared them on these outcomes.
• What retatrutide's label will say if it is approved. As of October 2026, it has not been filed with the FDA.
• Whether mechanism-based concerns about BPC-157 or TB-500 and tumor growth show up in people. As of October 2026, no human study has measured it.