Sermorelin vs CJC-1295 / Ipamorelin: choosing your GH peptide protocol

The two most-prescribed growth hormone peptide protocols in concierge medicine are sermorelin and CJC-1295 / Ipamorelin. Both prompt the pituitary to release the body's own growth hormone — preserving the natural pulsatile pattern that exogenous HGH suppresses. They are not the same protocol, and patient marketing tends to flatten the distinction.

Here's what actually separates them, and how a clinician chooses.

How GH release works

Growth hormone is released from the anterior pituitary in pulses — mostly at night, mostly during deep sleep. Two upstream signals drive these pulses:

• GHRH (growth hormone-releasing hormone) — produced in the hypothalamus, tells the pituitary to release GH
• Ghrelin / GHS-R activation — a separate pathway that also triggers GH release through the growth hormone secretagogue receptor

The two protocols differ in which of these pathways they hit.

Sermorelin — pure GHRH

Sermorelin is a 29-amino-acid fragment of human GHRH. It binds the GHRH receptor on the pituitary and stimulates the same pulse the body would produce naturally — just supplementally extended.

Pros: Long clinical history (FDA-approved formulation existed for years before being discontinued; the compound itself is well-understood). Gentle response curve. Single-pathway action means fewer interactions. Affordable. Well-tolerated by patients new to peptides.

Cons: Modest intensity of response — a meaningful but not dramatic increase in nightly GH pulses. Half-life is short (10–15 minutes), so timing matters. Doesn't hit the secretagogue pathway, so you're only tapping one of the two upstream signals.

CJC-1295 / Ipamorelin — dual mechanism

This is a combination protocol pairing two peptides. CJC-1295 is a modified GHRH analog with a longer half-life than sermorelin — extending GHRH signaling through the night. Ipamorelin is a selective ghrelin receptor agonist that triggers GH release through the secretagogue pathway, importantly without spiking cortisol or prolactin (a problem with older GHRPs like GHRP-2 and GHRP-6).

Pros: Hits both upstream pathways simultaneously — substantially stronger GH pulse than GHRH-only protocols. Ipamorelin's clean receptor profile avoids the cortisol/prolactin issues of older GHRP combos. Most patients report better sleep depth, more visible body-composition response, and faster recovery from training within 6–8 weeks.

Cons: More moving parts — two compounds in one injection, more dose variables. Slightly higher cost than sermorelin. Some patients are sensitive to the stronger response and prefer to start lower.

Side-by-side

• Mechanism. Sermorelin = GHRH only. CJC + Ipamorelin = GHRH + ghrelin pathway.
• Intensity. Sermorelin = modest. CJC + Ipamorelin = stronger.
• Sleep impact. Both improve deep sleep; CJC + Ipamorelin tends to be more pronounced.
• Body composition. Both help; CJC + Ipamorelin shows faster visible change in lean mass and visceral fat.
• Cortisol / prolactin. Sermorelin: no impact. CJC + Ipamorelin: clean (Ipamorelin specifically chosen for selectivity).
• Cost. Sermorelin is the lower-cost protocol; CJC + Ipamorelin runs higher.
• First peptide? Sermorelin is the gentler entry point. CJC + Ipamorelin is the protocol you graduate to (or start with, if your clinician thinks you'll do well on it).

A practical decision framework

1. First peptide ever? Sermorelin is the safer starting point — milder response, easier to assess tolerance, lower cost.
2. Sleep is your main goal? Both work; CJC + Ipamorelin tends to deepen slow-wave sleep more visibly.
3. Body composition is your main goal? CJC + Ipamorelin produces faster visible change, particularly around visceral adiposity and lean mass.
4. Recovery from training? CJC + Ipamorelin is the more responsive protocol, especially in patients training hard.
5. Budget-sensitive? Sermorelin remains the cost-effective entry — and works.
6. Want full coverage of both pathways? CJC + Ipamorelin. There's no GHRH-only protocol that replicates the dual-pathway response.

How Vektor selects between them

Most new peptide patients in our practice start on either sermorelin or CJC + Ipamorelin based on three factors: their response history with peptides, their primary goal (sleep vs body composition vs recovery), and their training intensity. We re-evaluate at week 6–8 with labs (IGF-1, fasting glucose, lipids) and a structured patient-reported assessment, and we adjust dose or switch protocol if the response doesn't match the goal.

Both protocols are sourced through our U.S. 503A pharmacy partner. Pricing and availability are reviewed transparently up front — no surprise add-ons after you've started.