Endocrinologists Graded the Growth Hormone Peptides. Three Got the Bottom Tier.
DR
Dr. Anna Chereshnevskyi · General Practitioner ·
Growth hormone peptides are sold as a single category, usually as a stack. A clinic or a forum recommends CJC-1295 with ipamorelin, and the implication is that these are interchangeable tools with a shared body of science behind them.
A review published in Frontiers in Endocrinology in June 2026, by endocrinologists at Poznan University of Medical Sciences, went through them one at a time and sorted them by the strength of the human evidence. The ladder has four rungs and the gap between top and bottom is enormous.
The ladder
Tier A, real randomized trials: tesamorelin, alone. It has randomized controlled trials in HIV-associated lipodystrophy, which is also the condition it is approved for.
Tier B, early human studies: most of the growth hormone releasing hormone analogues and secretagogues, including sermorelin, CJC-1295 with DAC, ipamorelin, and GHRP-6. These have Phase I and Phase II data showing they do raise growth hormone and IGF-1. What they lack is trials measuring whether that produces the outcomes people take them for, such as body composition.
Tier B/C: AOD9604, with limited short-term human trials.
Tier D, no peer-reviewed human studies at all: CJC-1295 without DAC, often sold as Modified GRF 1-29, plus PEG-MGF and IGF-1 LR3.
That bottom rung deserves a pause. These are not compounds with weak or mixed evidence. They are compounds with no published human research, sold and dosed as though they were understood.
Raising a hormone is not the same as a result
The distinction between Tier A and Tier B is the one that gets lost in marketing, and it is the same distinction we drew in our piece on semaglutide and Alzheimer's disease.
A Tier B peptide has been shown to increase growth hormone and IGF-1. That is a measurement. Whether higher IGF-1 in a healthy adult produces more muscle, less fat, better sleep, or faster recovery is a different question, and the review's point is that it has largely not been asked in properly designed trials.
The dosing nobody tested
The review makes an observation that is unusual to see stated plainly in a journal. The protocols people actually follow come from online forums, not from the studies.
The authors note that bodybuilding forums commonly recommend CJC-1295 with DAC at 1 to 2 mg weekly for cycles of 8 to 16 weeks, which is substantially higher and longer than any regimen that has been tested clinically. They describe these protocols as anthropological data, meaning a record of what people do, rather than evidence about what works.
So even for the peptides with some human data, the way they are used in practice sits outside the conditions under which that data was collected.
The risks the review does document
- Hormonal spillover. GHRP-2, GHRP-6, and hexarelin raise prolactin and cortisol. Ipamorelin is preferred in stacks partly because it does not, which is a genuine pharmacological difference rather than marketing.
- Appetite. The ghrelin-mimicking secretagogues stimulate hunger, which is worth knowing if the goal is fat loss.
- Blood sugar. Growth hormone opposes insulin, so dysglycemia and insulin resistance are plausible risks across the class. Short-term tesamorelin trials showed no major signal, but longer exposures have not been measured.
- Fluid retention. Documented with tesamorelin, including swelling and tingling in the limbs.
On cancer, the authors are careful and worth quoting accurately. Higher circulating IGF-1 is associated with increased risk of several cancers in epidemiological studies. That does not establish that any of these peptides causes cancer in humans, and short-term exposure cannot tell you about long-term risk. Their recommendation is that people be counseled about uncertain oncologic risk rather than reassured or alarmed.
The identity problem
The review raises one more issue that no dosing protocol can solve. These compounds circulate as research chemicals with uncertain purity, dose consistency, and sterility, which means a clinician seeing a patient with side effects cannot confirm what the patient actually took.
Everything we have documented this year supports that: testing where one vial in eighteen matched its label, forged certificates, and contaminated injectables.
What the authors conclude
They do not call for a ban, and they do not pretend the interest will go away. Their position is that clinicians should be able to identify and monitor harm without implicitly endorsing use, and that the line between those two things should be made explicit to the patient.
Their overall judgment is that absent regulatory approval, standardized dosing, and long-term safety surveillance, these compounds should generally be discouraged, with particular caution in anyone at elevated cancer risk.
It lines up closely with the UCLA review of 565 studies published weeks later, from a completely different specialty. Two independent groups looked at overlapping compounds and reached the same conclusion. Our growth hormone section sets out what is known for each one.
DR
Written by
Dr. Anna Chereshnevskyi
General Practitioner
Dr. Chereshnevskyi is a general practitioner who graduated from Lviv National Medical University and currently practices at a state hospital in Ankara, Turkey. She specialises in primary care and follows the clinical literature on peptide therapies, metabolic health, and longevity research. She contributes to Peptide.pub as a medical reviewer and blog author, translating complex research into plain, evidence-based language.
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