Growth Hormone Peptides: They Work. That Is The Problem

These Do Not Contain Growth Hormone

Worth clearing up first, because the marketing blurs it. Ipamorelin, CJC-1295, sermorelin, hexarelin and the GHRPs are not growth hormone. They are secretagogues: compounds that prompt the pituitary to release more of your own.

That distinction is the entire sales argument. Because it is your own hormone, released in your own pattern, it is presented as safer and more natural than injecting growth hormone directly.

It also means the chain of reasoning has two links, and almost all the discussion is about the first one:

1. Does the compound raise growth hormone?
2. Does raising growth hormone do anything you want?

The evidence on the first is genuinely strong. The evidence on the second is the part nobody puts on a product page.

The Trial Counts, Which Do Not Say What You Expect

Elsewhere in this section the count is the argument — BPC-157 has zero, epitalon has zero. That line is not available here, and using it would be false:

• GHRP-2: 204 records, 42 randomised trials
• Hexarelin: 312 records, 27
• Tesamorelin: 121 records, 26
• GHRP-6: 663 records, 20
• Sermorelin: 331 records, 19
• Ipamorelin: 54 records, 2
• CJC-1295: 33 records, 1

Two things fall out of that list.

First, the two sold hardest to consumers — ipamorelin and CJC-1295, usually together — are the two at the bottom. Three randomised trials between them.

Second, the ones with real evidence are not what is being sold. Sermorelin was an approved drug, Geref, and was discontinued. Tesamorelin is approved now, as Egrifta, for a specific condition. The GHRPs are largely 1990s and 2000s pharmacology from academic endocrinology.

The same shape as retatrutide and cagrilintide, arrived at from a different direction.

What Those 42 Trials Were Measuring

Open them and the endpoint is almost always the same: does growth hormone go up. Serum GH, IGF-1, dose-response curves, comparisons between secretagogues, timing of the pulse.

The answer is yes, robustly, and has been for thirty years. These compounds do what they say.

Which is a pharmacology question, not a clinical one. It establishes the mechanism and stops precisely where the interesting part begins. A trial showing that a compound raises a hormone tells you nothing about whether the person holding the syringe ends up stronger, leaner, or better.

So “42 randomised trials” is true, and it is the answer to a question about the pituitary rather than about the buyer.

So Somebody Tested The Second Link Directly

If the point of a secretagogue is to raise growth hormone, then the cleanest test of the whole idea is to skip the middleman: give people growth hormone itself, at doses that certainly work, and measure what happens.

That has been done many times, and pooled in a systematic review in the Annals of Internal Medicine. Forty-four articles describing 27 study samples. 303 participants received growth hormone, representing 13.3 person-years of treatment.

The participants were the population this is sold to: mean age 27, mean BMI 24, mean VO₂ max 51. Young, lean and fit.

What happened:

• Lean body mass increased by 2.1 kg (95% CI 1.3 to 2.9).
• Strength did not appear to improve.
• Exercise capacity did not appear to improve.
• Lactate during exercise was significantly higher in two of the three studies that measured it.
• Soft tissue oedema and fatigue were more frequent than in untreated participants.

The reviewers' conclusion: claims that growth hormone enhances physical performance are not supported by the scientific literature.

What 2.1 Kilos Of Lean Mass Without Strength Means

Take the two findings together, because separately each is misleading and together they say something specific.

Lean body mass went up. Strength did not. Those are hard to reconcile if the added mass were contractile muscle tissue, because more muscle is generally stronger muscle.

Now read the adverse events in the same review: soft tissue oedema was more frequent. Growth hormone causes fluid retention, and retained fluid is measured as lean mass by every method that separates fat from not-fat.

The review does not assert that the 2.1 kg was water, and neither will this page. But a lean-mass gain that produces no strength gain, in the presence of documented oedema, is not the result someone is buying when they buy this.

It is also a useful reminder for reading any body-composition claim: “lean mass” is everything that is not fat, including water and glycogen. The measure people care about is muscle that does something, and the test for that is whether it lifts more.

Which is the whole problem with this category in one line: the peptides raise growth hormone, growth hormone adds lean mass, and the lean mass does not make you stronger.

The One That Is Actually Approved

Tesamorelin is worth its own note, because it shows what happens when one of these is developed properly. 121 records, 26 randomised trials, and approval as Egrifta.

What it is approved for: reduction of excess abdominal fat in people with HIV-associated lipodystrophy. A specific condition, in a specific population, with a specific mechanism — not general body recomposition, not anti-ageing, not performance.

Sermorelin makes the opposite point. It was approved as Geref and has been discontinued, which is not the trajectory of a compound that turned out to be broadly useful.

Between them they map the category: where a growth hormone secretagogue has been taken through proper development, it has ended up either treating one narrow condition or leaving the market. Neither outcome supports the version sold to healthy adults for physique.

And the intervention that reliably adds contractile tissue in healthy adults has never needed a pituitary at all: progressive resistance training with enough protein. It produces strength along with the mass, which is the part the hormone did not.