Peptide Therapy Contraindications You Should Know

The right time to learn about peptide-therapy contraindications is at intake, not after starting a protocol. A competent clinician screens for them during the initial visit, asks about family history, reconciles the full medication list, and excludes patients for whom the risk-benefit math does not work. This article describes what that screen actually covers — both the universal contraindications that apply across peptide classes and the class-specific ones that matter for GLP-1, GHRH peptides, NAD+, and tissue-repair peptides.

The point of the screen is not to find a reason to refuse the patient. The point is to make sure the patient who proceeds is the patient for whom the protocol is genuinely safe.

The universal contraindications

A few exclusions apply broadly across most peptide classes used in therapy.

Pregnancy. Pregnancy is an exclusion for essentially all elective peptide therapy. Most peptide classes lack pregnancy safety data, and the clinical posture is conservative: patients who are pregnant or actively trying to conceive do not start or continue peptide therapy. For patients on a peptide protocol who become pregnant, the clinician's standard response is to discontinue and revisit after pregnancy and breastfeeding are complete.

Breastfeeding. The same logic extends through breastfeeding. Some peptides are large molecules unlikely to be excreted in clinically meaningful amounts, but the safety data in nursing infants is generally absent. Conservative practice excludes breastfeeding patients from elective peptide therapy.

Active malignancy. Patients in active cancer treatment, or with recently active untreated cancer, are not candidates for elective peptide therapy. Several peptide classes interact with growth pathways either directly (GHRH peptides increase endogenous growth hormone) or theoretically (GLP-1 receptor signaling has been studied across multiple tissue types). The conservative posture is to exclude active-malignancy patients categorically and to evaluate remote cancer history individually based on type, treatment history, and time since remission.

Severe uncontrolled comorbid disease. Patients with severe uncontrolled cardiovascular, renal, hepatic, or psychiatric disease are not appropriate for elective peptide protocols until the underlying condition is stabilized. The decision is medical, not categorical — what counts as "stable" depends on the specific disease and the specific peptide.

GLP-1 receptor agonist contraindications

The GLP-1 class has the most explicit, label-defined contraindication set, accumulated through years of clinical trials and post-marketing surveillance.

Personal or family history of medullary thyroid carcinoma (MTC). This is an absolute contraindication for the GLP-1 receptor agonist class. The basis is rodent preclinical data showing thyroid C-cell tumors at high doses. Whether the human risk mirrors the rodent finding has been debated, but the labeled contraindication is conservative and clinical practice respects it without exception. Patients with personal or family history of MTC are not candidates for GLP-1 therapy.

Multiple Endocrine Neoplasia Type 2 (MEN2). MEN2 is a hereditary syndrome that predisposes to MTC and is excluded on the same basis. Patients who are aware of a MEN2 family history disclose it during intake; some patients first learn about it during the family-history portion of the screen.

History of pancreatitis. Pancreatitis has been reported in association with GLP-1 use. The label warns about it; clinical practice generally excludes patients with a history of pancreatitis, particularly recent or recurrent episodes. Remote single-episode history with a clearly identified non-recurrent cause is sometimes evaluated case by case.

Severe gastroparesis or active inflammatory bowel disease. Because GLP-1s slow gastric emptying and commonly produce gastrointestinal effects, patients with pre-existing severe gastroparesis or active IBD are at higher risk of clinically significant symptoms. These conditions are typically exclusions or warrant careful individualized evaluation.

Type 1 diabetes. GLP-1 receptor agonists are not approved for type 1 diabetes, and use in T1D patients is generally not appropriate outside of carefully designed clinical contexts. Patients with type 1 diabetes are typically not candidates for elective GLP-1 therapy through standard peptide clinics.

GHRH peptide contraindications

Sermorelin, ipamorelin, tesamorelin, and CJC-1295 stimulate endogenous growth hormone production. The contraindications follow from that mechanism.

Active malignancy. As above, the conservative posture is to exclude patients with active or recent active cancer. Growth hormone has known proliferative interactions, and stimulating endogenous GH release in patients with active malignancy is contraindicated.

Multiple Endocrine Neoplasia syndromes. MEN1 and MEN2 syndromes affect endocrine signaling and are typically exclusions for GHRH peptide therapy. Patients with personal or family history of MEN syndromes require endocrinology consultation before any growth-hormone-related intervention.

Proliferative diabetic retinopathy. Growth hormone exposure has been associated with worsening of proliferative diabetic retinopathy in some clinical contexts. Patients with active proliferative retinopathy are typically excluded from GHRH peptide therapy.

Severe untreated sleep apnea. Growth hormone stimulation can in some patients exacerbate sleep-disordered breathing. Patients with severe untreated sleep apnea are typically not started on GHRH peptide therapy until the apnea is appropriately managed.

Acute critical illness. GHRH peptide therapy is not appropriate during acute critical illness — for example, in the ICU setting or during severe acute infection.

Pituitary or hypothalamic disease. Patients with pituitary tumors, prior pituitary surgery, or known hypothalamic-pituitary axis dysfunction require endocrinology evaluation before GHRH peptide therapy is considered. The clinical picture is individualized and not always exclusionary, but it is not a routine intake.

NAD+ injectable contraindications

NAD+ has fewer hard contraindications than the GLP-1 or GHRH classes, but several patient profiles warrant careful evaluation or exclusion.

Active malignancy. As across all peptide classes, active malignancy is generally an exclusion. The mechanistic relationship between NAD+ supplementation and tumor biology is an area of ongoing research, and the conservative posture is to defer NAD+ therapy in patients with active cancer.

Severe cardiovascular disease. Patients with severe uncontrolled cardiovascular disease are typically not started on injectable NAD+ until the underlying disease is stabilized. The flushing and transient hemodynamic effects of NAD+ injection can be clinically meaningful in this population.

Recent significant surgery or hospitalization. NAD+ injectable therapy is typically deferred until acute medical events are resolved.

Drug interactions a clinician reconciles

The intake medication review covers more than contraindications — it identifies interactions that change dosing or require monitoring.

GLP-1 and oral medications. Because GLP-1 agonists slow gastric emptying, the absorption of co-administered oral medications can be affected. Most clinically meaningful interactions involve narrow-therapeutic-index drugs (warfarin, certain anticonvulsants, certain immunosuppressants). The clinician adjusts timing or monitors levels rather than excluding the patient.

GLP-1 and insulin or sulfonylureas. In patients with diabetes, GLP-1 agonists amplify the glucose-lowering effect of insulin and sulfonylureas. This routinely requires dose reduction of those agents to avoid hypoglycemia and is part of the standard intake conversation for diabetic patients.

GHRH peptides and corticosteroids. Chronic corticosteroid therapy can blunt growth hormone responsiveness and complicate the interpretation of GHRH peptide therapy outcomes. The interaction does not always exclude the patient but does affect dosing and monitoring.

Drug-induced hypoglycemia awareness. Several non-diabetes medications interact with the metabolic effects of peptide therapy in ways the clinician needs to know about. The intake reconciliation is the place this surfaces.

Patient profiles where caution outweighs benefit

Beyond formal contraindications, several patient profiles warrant a frank "this is probably not the right intervention right now" conversation rather than a protocol.

Eating disorder history. Patients with active or recent active anorexia nervosa, bulimia, or other eating disorders are not appropriate candidates for GLP-1 or other appetite-modifying peptide therapy. The risk of disordered patterns being reinforced by a pharmacological appetite signal outweighs the benefit. This is one of the most important screen points and is sometimes missed in less rigorous intake processes.

Underweight BMI. Patients with BMI below a healthy threshold are not candidates for weight-loss-focused GLP-1 therapy. Microdose protocols are sometimes appropriate for patients near a healthy BMI for composition reasons, but the floor for any GLP-1 protocol is a BMI clearly within the healthy range.

Significant unstable mental health. Active uncontrolled depression, suicidal ideation, or severe anxiety can be worsened by some peptide-class adverse effects and complicate the patient's ability to manage a self-injection protocol. Stabilization of mental health usually precedes initiation of peptide therapy.

Inability to commit to clinical follow-up. Peptide therapy is not a one-and-done prescription. A patient who cannot commit to follow-up visits, lab review, and dose-adjustment cadence is a poor candidate regardless of clinical eligibility.

What a thorough intake actually looks like

A peptide-therapy intake that takes the contraindication question seriously covers, at minimum:

• Personal medical history including all current and recent diagnoses
• Family history of MTC, MEN syndromes, and significant endocrine disease
• Cancer history including type, treatment, and time since remission
• Current medications and supplements
• Pregnancy and breastfeeding status
• Mental health history including eating disorder history
• Recent or active gastrointestinal disease for GLP-1 candidates
• Cardiovascular and renal status
• Current labs as indicated by the protocol under consideration

A clinic that does not collect this information at intake is not screening adequately. A clinic that collects it but does not act on it — that prescribes regardless of what the answers are — is doing something other than clinical practice.

How TelePeptide handles the screen

The TelePeptide intake covers the full contraindication checklist for the peptide class under consideration. Patients with absolute contraindications are not started on the protocol; in many cases the clinician can suggest a different peptide class that fits the patient's situation, and in some cases the right answer is no peptide therapy at this stage. The screen is the same whether the protocol is microdose GLP-1, standard-dose GLP-1, NAD+, or GHRH peptide therapy — the contraindication set differs by class, and the intake covers each class's specific exclusions before any prescription is written.

Compounded medications are prepared by licensed 503A pharmacies. Prescribing decisions are made solely by licensed clinicians based on individual medical necessity. These statements have not been evaluated by the FDA. Compounded medications are not FDA-approved.