CJC-1295 / Ipamorelin →
The most widely prescribed GH-secretagogue combination. GHRH analog + selective ghrelin mimetic. Phase 2 human PK data; preclinical selectivity evidence.
Compounds in this class
Each compound has its own deep dive.
Want the full picture on one specific GH secretagogue? Each page below covers mechanism, the most-cited clinical evidence (with PMIDs), typical dosing context, safety considerations, and 2026 regulatory status.
Sermorelin →
GHRH(1-29) analog with the longest clinical safety record in this class — historically FDA-approved as Geref. Strong 503A regulatory footing.
Tesamorelin (Egrifta) →
The only GH secretagogue with current FDA approval (NDA 022505, 2010). Phase 3 RCT evidence in HIV-associated lipodystrophy. Off-label use exists in a documented gray zone.
MK-677 / Ibutamoren →
Orally bioavailable, non-peptide ghrelin agonist. Investigational status, real glucose and CHF-signal concerns, and a complicated 503A picture. Educational page only.
Mechanism of action
How GH secretagogues work — and why they differ from HGH.
Growth hormone secretagogues are a heterogeneous class of peptides and small molecules that stimulate the pulsatile secretion of endogenous GH from the anterior pituitary. Rather than administering synthetic GH directly, these compounds work upstream — signaling the body's own GH-releasing machinery. This distinction is clinically meaningful: endogenous GH secretion remains pulsatile and subject to negative feedback, which is theoretically protective compared to exogenous rhGH.
GHRH Analogs — CJC-1295, Sermorelin, Tesamorelin
These peptides mimic or are structurally related to growth hormone-releasing hormone (GHRH) — the hypothalamic signal that triggers pituitary GH release. They bind to GHRH receptors on somatotroph cells in the anterior pituitary, stimulating GH secretion in the same physiological manner as endogenous GHRH. CJC-1295's "drug affinity complex" (DAC) modification extends its half-life, enabling less frequent dosing than native GHRH. Tesamorelin is a stabilized GHRH analog and the only FDA-approved compound in this class for any body composition indication.
Ghrelin Mimetics — Ipamorelin, MK-677 / Ibutamoren
These compounds bind to the growth hormone secretagogue receptor (GHS-R1a), also known as the ghrelin receptor. Ghrelin — the "hunger hormone" — naturally stimulates GH release through this receptor; ipamorelin and MK-677 replicate this action. Ipamorelin's critical clinical advantage over older GHRP-class compounds (GHRP-2, GHRP-6) is its selectivity: it produces potent GH release without substantially elevating cortisol, ACTH, or prolactin. MK-677 is uniquely orally bioavailable — unlike all other GHS peptides, it does not require injection.
CJC-1295 + Ipamorelin — The Combination
The CJC-1295 + ipamorelin combination is widely used clinically because the two mechanisms are synergistic: GHRH analogs prime the pituitary while ghrelin mimetics amplify the GH pulse. Together they produce greater GH release than either agent alone — a rationale supported by pharmacodynamic reasoning, though direct combination-protocol RCTs in humans are limited.
What "Pulsatility" Means for Safety
Natural GH secretion occurs in pulses — 6–12 per day in young adults, with the largest pulse during slow-wave sleep. Exogenous rhGH creates sustained, non-pulsatile GH exposure that suppresses the pituitary. GHS peptides preserve pulsatile release and leave the negative feedback axis intact, which most clinicians view as a safer long-term profile — though direct long-term safety comparative data between GHS and rhGH approaches in adults are absent.
What patients explore it for
Common therapeutic goals and clinical applications.
Patients and clinicians explore GHS compounds for several goals. Most fall outside FDA-approved indications and are managed in clinical telehealth programs under off-label prescribing frameworks.
Body Composition Optimization
Reduction of visceral and subcutaneous fat; increase in lean muscle mass and quality — particularly in middle-aged adults experiencing age-related GH decline (somatopause). Tesamorelin's FDA-approved data show mean VAT reductions of 24 cm² versus placebo in Phase 3 trials.
Sleep Quality
GH is secreted primarily during slow-wave sleep. Many patients report subjectively improved sleep quality with low-dose GHS use, particularly with bedtime-timed protocols. This is consistent with the mechanism but has not been validated in controlled human trials for non-approved GHS compounds.
Recovery and Longevity Protocols
Mitigating age-related decline in GH/IGF-1 axis activity — supporting connective tissue, bone, and muscle recovery. GH plays a recognized role in cellular repair and regeneration. Long-term longevity outcomes have not been evaluated in RCTs.
Metabolic Health
Potential improvement in insulin sensitivity (with monitoring), lipid profiles, and visceral adiposity. Tesamorelin's trial data showed improvements in triglycerides and cholesterol-to-HDL ratio alongside visceral fat reduction. Glucose parameters must be monitored — particularly with MK-677, which significantly raises fasting glucose.
Post-Surgical and Injury Recovery
Some clinicians incorporate GHS protocols into broader post-surgical or sports injury recovery programs, drawing on GH's role in collagen synthesis and tissue repair. Evidence is largely indirect, extrapolated from GH deficiency research and tesamorelin trials. High-quality RCTs in sports injury contexts are absent.
HIV-Associated Lipodystrophy
Tesamorelin's FDA-approved indication: excess abdominal fat accumulation in HIV-infected patients on antiretroviral therapy, where lipodystrophy causes significant metabolic and body image consequences. This is the most evidence-supported application in the GHS class.
Evidence summary
Clinical evidence across the GHS class.
Clinical evidence exists across a spectrum — tesamorelin has the strongest (Phase 3 RCT, FDA-approved); CJC-1295 and ipamorelin have Phase 2 human data; MK-677 has several small human RCTs; sermorelin has the longest clinical safety record from pediatric use. All PMIDs below are verified against PubMed.
CJC-1295 — Phase 2 Human Trial
PMID: 17018654 · Ionescu & Frohman, JCEM 2006 · Evidence: Level II
In a dose-escalation study of healthy adult volunteers, a single injection of CJC-1295 (60 or 90 mcg/kg) increased mean GH concentrations by 46% and IGF-1 levels by 45%, with preserved pulsatility of GH secretion. Elevated GH and IGF-1 persisted for 6 days post-injection. This remains the primary human pharmacokinetic and pharmacodynamic reference for CJC-1295 and established the DAC modification as enabling prolonged GHRH receptor engagement without desensitization.
Ipamorelin — Foundational Pharmacology
PMID: 9849822 · Raun et al., Eur J Endocrinol 1998 · Evidence: Level IV (preclinical)
The foundational paper establishing ipamorelin as "the first selective growth hormone secretagogue." In rats and conscious swine, ipamorelin produced potent, dose-dependent GH release with selectivity comparable to GHRH — without the ACTH and cortisol elevation characteristic of GHRP-2 and GHRP-6. This selectivity — GH release without HPA-axis activation — defines ipamorelin's clinical appeal. Note: this is preclinical data; large human RCTs for ipamorelin in adults remain limited.
MK-677 — Elderly RCT
PMID: 8954023 · Chapman et al., JCEM 1996 · Evidence: Level II
In healthy elderly subjects (mean age ~65), daily oral MK-677 25 mg for 2 weeks increased mean 24-hour GH concentration by 97% and raised serum IGF-1 into the normal range for young adults (141 → 265 mcg/L). Fasting glucose increased significantly (5.4 → 6.8 mmol/L at 4 weeks) — a critical finding highlighting insulin resistance risk with ibutamoren, particularly in pre-diabetic patients. One of the most-cited human trials establishing GHS-R1a agonism by an oral agent.
Tesamorelin — Phase 3 Pooled Analysis
PMID: 20554713 · Falutz et al., JCEM 2010 · Evidence: Level I
The pivotal regulatory dataset supporting tesamorelin's FDA approval. In a pooled analysis of two Phase 3 double-blind RCTs (n=806 HIV+ patients with lipodystrophy), tesamorelin 2 mg/day significantly reduced visceral adipose tissue by −24 cm² vs. +2 cm² with placebo at 26 weeks (treatment effect −15.4%, p<0.001). Triglycerides, cholesterol-to-HDL ratio, and body image scores also improved. This is Level I evidence — the only GHS compound with this designation for a body composition endpoint.
Tesamorelin — 2026 Meta-Analysis
DOI: 10.1016/j.orcp.2026.01.002 · Badran et al. 2026 · Evidence: Level I (meta-analysis)
This 2026 meta-analysis of 5 RCTs confirmed tesamorelin significantly reduced VAT (MD = −27.71 cm², p<0.001), trunk fat, hepatic fat, and waist circumference while increasing lean body mass (MD = +1.42 kg, p<0.001) in HIV-related lipodystrophy. Treatment was well tolerated with no major safety signals beyond musculoskeletal complaints (arthralgia, myalgia) and injection site reactions. Strengthens the Phase 3 evidence base with pooled RCT data.
Systematic Review — GHS in Hypogonadal Males
DOI: 10.21037/tau.2019.11.30 · Sinha et al. 2020 · Evidence: Level III (systematic review)
This systematic review synthesized evidence on sermorelin, GHRP-2, GHRP-6, ibutamoren, and ipamorelin in men with hypogonadism or metabolic syndrome. Conclusion: all are potent GH/IGF-1 stimulators with favorable body composition effects in preclinical and limited human data, but "a paucity of data examining clinical effects currently limits our understanding." High-quality long-term RCTs are needed. An honest and important summary of the evidence state as of 2020.
Dosing context — educational only
What clinical protocols look like.
⚠ EDUCATIONAL ONLY — Not a Prescription
The dosing information below describes ranges used in clinical telehealth settings and published research, for educational purposes only. It is not a prescription, recommendation, or individualized guidance. All dosing decisions are made exclusively by a licensed prescribing clinician based on your complete health history, baseline IGF-1 levels, current medications, metabolic markers, and clinical assessment. Do not initiate or adjust any medication based on this content.
CJC-1295 + Ipamorelin Combination
Commonly blended. Typical clinical ranges: CJC-1295 (without DAC) ~100–200 mcg + ipamorelin ~100–300 mcg per injection, subcutaneous, once or twice daily. Some protocols use CJC-1295 with DAC at lower frequency (1–2x/week) due to extended half-life. Duration: typically 3–6 month cycles with IGF-1 monitoring. Route: subcutaneous injection.
Sermorelin
Historically used for adult GH optimization. Typical subcutaneous doses range from 100–500 mcg at bedtime, to align with the natural nocturnal GH pulse. Shorter half-life than CJC-1295 DAC analogs. Has the longest clinical safety record of non-approved GHS compounds due to decades of use in pediatric GHD diagnosis (as Geref®, now withdrawn from market but with extensive safety data).
Tesamorelin
FDA-approved dose: 2 mg subcutaneous once daily for HIV lipodystrophy. Off-label use in non-HIV populations exists at similar dosing; no FDA-approved indication exists outside the HIV context. Contraindicated in patients with hypothalamic-pituitary axis disruption (hypophysectomy, pituitary tumor, head irradiation) and in pregnancy.
MK-677 / Ibutamoren
Oral administration, typically 12.5–25 mg daily. Important regulatory note: ibutamoren is not FDA-approved for any indication and is classified as an investigational drug. It is not on any compounding bulks list and cannot be legally dispensed through standard 503A compounding programs. Sometimes sold as a "research chemical" — this does not constitute a legal pathway for human use.
IGF-1 monitoring is standard practice in any clinical GHS program to assess response and prevent supraphysiologic IGF-1 levels. Baseline labs and follow-up panels are part of responsible GHS clinical protocols.
Safety & contraindications
What your clinician needs to evaluate.
Common Adverse Effects
Water retention and peripheral edema (particularly at initiation; usually resolves). Joint discomfort or carpal tunnel syndrome-like symptoms related to GH-mediated fluid shifts. Transient numbness or tingling. Increased appetite, particularly with ipamorelin and MK-677 via ghrelin receptor activation. These effects are dose-dependent and often resolve with protocol adjustment.
Active Malignancy — Primary Safety Concern
GH and IGF-1 have mitogenic (cell growth-promoting) activity. Use in patients with active cancer or significant personal/family history of hormone-sensitive tumors requires careful clinician risk-benefit evaluation. This is the primary theoretical safety concern with all GHS peptides in the long term. Cancer history must be disclosed and evaluated before initiating any GHS protocol.
Glucose and Insulin Resistance
GHS agents — especially MK-677 — can raise fasting blood glucose and worsen insulin sensitivity. Clinically significant glucose elevation was observed in the Chapman 1996 MK-677 RCT. Regular monitoring of fasting glucose and HbA1c is appropriate. Pre-diabetic patients require careful monitoring and may not be appropriate candidates for certain GHS compounds.
Acromegaly Risk at High Doses
Chronically supraphysiologic IGF-1 levels carry theoretical risks including acromegalic features — joint enlargement, soft tissue changes, carpal tunnel syndrome, and headaches. IGF-1 monitoring throughout the protocol is the primary mitigation strategy. Clinicians should target IGF-1 within an age-appropriate physiological range, not supraphysiologic levels.
Tesamorelin-Specific Contraindications
Contraindicated in patients with disruption of the hypothalamic-pituitary axis due to hypophysectomy, pituitary tumor, or head irradiation. Contraindicated in pregnancy. Not recommended in active malignancy. These contraindications apply to the FDA-approved indication and are medically important baselines for any tesamorelin use.
MK-677 Cardiac Caution
One clinical trial reported worsening of congestive heart failure symptoms in patients with CHF. MK-677 should be used with caution in patients with cardiac conditions. The compound's investigational drug status also means that its full safety profile in diverse patient populations remains incompletely characterized.
Regulatory status — May 2026
What's approved, what's compoundable, and what's under review.
Tesamorelin — The Only FDA-Approved GHS for Body Composition
Tesamorelin (Egrifta®) received FDA approval in 2010 (NDA 022505) for treatment of excess abdominal fat in HIV-infected patients with lipodystrophy. This is the only FDA-approved GHS compound for an adult body composition indication. Compounded tesamorelin for off-label use in non-HIV populations operates in a regulatory gray zone — prescribers should document individualized clinical rationale and confirm current pharmacy compliance guidance.
CJC-1295, Ipamorelin, and the July 2026 PCAC Meeting
CJC-1295 and ipamorelin are not FDA-approved for any indication. Both have been nominated for the FDA's 503A bulks list and were on the Category 1 evaluation list (under active consideration) as of early 2026. The FDA's Pharmacy Compounding Advisory Committee (PCAC) meeting scheduled for July 23–24, 2026 is expected to address multiple peptides including GHS compounds. Legal compounding under 503A requires appearing on the approved bulks list or being a component of an FDA-approved drug — consult current pharmacy compliance guidance for status.
Sermorelin
Previously FDA-approved for pediatric GHD diagnosis (Geref®); approval was voluntarily withdrawn by the manufacturer. Compounding of sermorelin for adult use is legal under 503A as it appears on several state and compounding pharmacy formularies. Not on the federal 503A bulks list as of mid-2026.
MK-677 — Investigational Drug
Not FDA-approved, not on any compounding bulks list, classified as an investigational new drug. Prescribing or compounding MK-677 carries significant regulatory risk. It is not appropriate for telehealth programs operating under standard 503A compounding pathways. Sometimes sold as a "research chemical" — this does not constitute legal authorization for human administration.
WADA note: Ipamorelin, CJC-1295, sermorelin, and tesamorelin are all prohibited in competitive sports under the WADA Prohibited List (peptide hormones and related substances). This does not affect clinical use by non-athletes but is important for patients who compete in sanctioned sports to understand before initiating any protocol.
FAQ
Common questions about GH secretagogues.
How are these different from HGH injections?
GHS peptides stimulate your pituitary to release its own growth hormone, preserving natural pulsatility and negative feedback. Exogenous recombinant HGH bypasses this system entirely and suppresses the pituitary's own production. Most clinicians view the GHS approach as more physiologically nuanced for long-term use — though comprehensive long-term comparative safety data are limited for both approaches.
How long until I notice results?
IGF-1 levels typically rise within 2–4 weeks. Body composition changes — reduced fat mass, improved lean mass — are generally noticed within 8–12 weeks, with more pronounced effects at 3–6 months. Sleep quality improvements are often reported within the first 2–4 weeks. Response depends on baseline IGF-1 levels, age, lifestyle, and specific compounds used.
Will these affect cortisol or testosterone?
GHS peptides primarily act on the GH/IGF-1 axis. Ipamorelin's key advantage is that it does not meaningfully elevate cortisol or ACTH, unlike older GHRPs. Your clinician should obtain baseline hormone panels before starting and monitor throughout treatment, including IGF-1, fasting glucose, and relevant metabolic markers.
Is MK-677 available through a compounding pharmacy?
No. MK-677 is classified as an investigational new drug and is not on any legal compounding bulks list. Standard 503A telehealth compounding programs cannot legally dispense it. It is sometimes sold as a research chemical, which does not constitute a legal pathway for human use.
Can GHS peptides help with injury recovery?
GH plays a recognized role in connective tissue synthesis and repair. Some clinicians use GHS protocols as part of broader recovery programs. Evidence is largely indirect — extrapolated from GH deficiency research and tesamorelin trials — not from controlled trials evaluating GHS peptides specifically for sports injuries. High-quality human RCTs in this context are absent.
Do I need to cycle off these peptides?
Many clinical programs use 3–6 month treatment cycles with 1–2 month breaks to prevent receptor desensitization and pituitary downregulation. This is a clinical judgment based on your individual IGF-1 response, treatment goals, and the specific compounds used. Cycling is not universally required and depends on the protocol and prescriber assessment.
Informational only. Content on this page is for informational purposes and does not constitute medical advice. All prescriptions are issued at the sole discretion of the prescribing clinician. Growth hormone secretagogue prescribing requires a complete clinical evaluation including IGF-1 baseline, glucose metabolism assessment, cancer history review, and ongoing monitoring. Not all compounds are available in all states. Last reviewed: May 2026.
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