Ipamorelin

The story

1. ~1995–1997 Novo Nordisk chemistry programme derives a pentapeptide from GHRP-1 by deleting the central Ala-Trp dipeptide; internal code NNC 26-0161
2. 1998 Raun et al. publish "Ipamorelin, the first selective growth hormone secretagogue" — the ACTH/cortisol selectivity data come from conscious swine
3. 1999 Only published human trial of ipamorelin as a GH secretagogue: dose-escalation PK/PD in 40 healthy male volunteers
4. 1999–2001 Rat work on longitudinal bone growth, bone mineral content, and counteracting glucocorticoid-induced bone and muscle loss — the mechanistic basis for later "healing" and "recovery" marketing
5. 2008–2009 NCT00672074, a Phase 2 placebo-controlled trial in postoperative ileus, runs under a sponsor registered under the name Helsinn Therapeutics
6. 2011–2014 NCT01280344, a 320-patient quadruple-masked Phase 2 dose-finding trial, runs under the same sponsor name — registered under the name Helsinn Therapeutics. Completed 2014-05; results never posted or published
7. 2014 Beck et al. publish the 117-patient ileus trial: well tolerated, no significant efficacy difference from placebo (p = 0.15)
8. 2018–2019 Ipamorelin and glycine-modified analogues identified in seized black-market growth-promoting products
9. 2026 Independent analysis of 6,441 gray-market peptide samples — including ipamorelin — finds 41.6%–71.1% failing basic quality criteria and endotoxin in 15%

What it does

• growth hormone (pulsatile release)
• IGF-1

What the evidence shows

Two published human interventional trials of ipamorelin exist, total n=154. Both were intravenous, neither ran longer than about a week, and the only one carrying an efficacy endpoint — postoperative ileus, n=114, randomized, double-blind, placebo-controlled — did not beat placebo; the largest trial ever run on the molecule, 320 patients and quadruple-masked, completed in 2014 and has never reported, and its registry record is cited here only for the fact that it exists, records completion and has posted nothing (NCT01280344, T2). The compound's defining commercial claim — growth hormone release without cortisol, ACTH or prolactin elevation — rests on a single 1998 experiment in conscious swine, in which the prolactin half was not a point of difference at all, because prolactin did not move for the comparator secretagogues either. No human study of ipamorelin has ever measured cortisol, ACTH or prolactin, and none has ever measured IGF-1.

Overall evidence strength: Low certainty

• Gobburu JV, Agersø H, Jusko WJ, Ynddal L (1999) — dose-escalation PK/PD in healthy volunteers (1999) Randomized controlled trial

  Source PMID 10496658

• Beck DE, Sweeney WB, McCarter MD (2014) — postoperative ileus (2014) Randomized controlled trial

  Source PMID 25331030

• NCT01280344 (2011–2014) — the missing trial Randomized controlled trial

  NCT01280344

  Source

• Raun K et al. (1998) — the selectivity paper (1998) Preclinical / mechanistic

  Source PMID 9849822

• Lall S et al. (2001) — adiposity (2001) Preclinical / mechanistic

  Source PMID 11162489

• Andersen NB et al. (2001) — glucocorticoid catabolism (2001) Preclinical / mechanistic

  ---

  Source PMID 11735244

Who it's for, who should skip

Only under direct physician supervision, and only where the regulatory status permits. Its status is currently gray — trackers report it as unavailable via licensed channels pending litigation. Not for anyone with active or recent cancer, or who is pregnant.

Skip it if

• active or recent cancer — GH-axis agents are contraindicated in active or recent malignancy — growth signaling can accelerate tumor growth. hard block
• pregnancy — Contraindicated in pregnancy. hard block

Running it

No dosing protocol is published for this compound — there is no lawful supervised channel for the use this guide covers. What follows is monitoring, expectations, and safety framing only.

Form

injectable

What to expect

• Acute (hours) — A single intravenous dose produces one episode of GH release, peaking at about 0.67 hours and declining exponentially to negligible concentrations. Dose-proportional kinetics; terminal half-life about 2 hours. This was seen at every dose level tested in 40 healthy men (Confidence: Trial-documented (PMID 10496658))
• Onset (days) — In postoperative patients, twice-daily IV dosing produced a median time to first tolerated solid meal of 25.3 h vs 32.6 h on placebo — a difference that did not reach significance (p = 0.15) (Confidence: Trial-documented, negative (DOI 10.1007/s00384-014-2030-8))
• Tolerance / plateau — Not characterised in humans; no dose-response or duration-response data beyond the single-dose PK/PD study, and the one trial that tested three dose levels has never reported. In rats given ipamorelin for 21 days, somatotroph percentage and GH cell-type ratios were unchanged (Confidence: Preclinical only / No data (PMID 12168778; NCT01280344 — T2 — registry record, self-asserted, unverified, supporting the absence finding only))
• Post-cessation — Not studied in humans. Systemic exposure clears within hours given the ~2 h half-life; nothing documents what happens to any claimed benefit afterward (Confidence: No data)
• Long-term — No data of any kind. The longest human exposure described in any registered trial is the up-to-ten-day regimen in NCT01280344's own arm descriptions (T2 — registry record, self-asserted, unverified) — and that trial never reported, so ten days is a statement about what a record says was to be given, not about anything observed. The longest human exposure with a published outcome is seven days. FDA concluded non-clinical toxicity studies were "too limited in scope and duration to inform safety considerations" (FDA) (Confidence: No data)

Response signs

Getting it right

• Monitoring: Establish a baseline before, not after. Tracking any marker from a pre-exposure baseline is what makes a later change interpretable. There is no validated efficacy biomarker for ipamorelin, so any monitoring plan here is safety monitoring, not effectiveness monitoring. mitigate side effect
• Monitoring: Glucose is the marker with actual ipamorelin evidence behind it. Hyperglycemia was reported among adverse events in the intravenous POI program, and FDA declined to conclude that ipamorelin would not carry the glucose-intolerance and diabetes concerns associated with approved GH-stimulating products (FDA). mitigate side effect
• Monitoring: Potassium too. Hypokalemia appears in the same adverse-event list, and it is not a marker most peptide panels include by default. mitigate side effect
• Monitoring: IGF-1 is the marker people expect to use, and it has never been measured for ipamorelin in a human. Tracking it is reasonable as a class-level surrogate; interpreting a number against published ipamorelin data is impossible, because there is none. mitigate side effect
• Monitoring: Time-box the question. The longest human exposure with a published outcome is seven days; the longest described in any registered trial is the up-to-ten-day regimen in NCT01280344's own arm descriptions (T2 — registry record, self-asserted, unverified), and that trial never reported. Open-ended use sits entirely outside the observed window of every study ever conducted, in every species. mitigate side effect
• General safety: Product identity is a first-order risk. Independent testing of 6,441 gray-market peptide samples across fourteen compounds including ipamorelin found 41.6%–71.1% failing basic quality criteria depending on framework, and measurable endotoxin in 15% (Mendias & Awan). A seller-supplied certificate of analysis is not independent verification — and FDA noted the CoAs submitted with the ipamorelin nominations lacked tests for impurities, aggregates and bacterial endotoxins (FDA). mitigate side effect
• General safety: Analogues circulate in the same market. Danish customs seizures contained ipamorelin, GHRP-2, GHRP-6 and modified GRF (1-29) analogues carrying an extra N-terminal glycine (DOI 10.1002/dta.2489). mitigate side effect
• General safety: The subcutaneous route has no human safety data of any kind. FDA states it in terms: "There are no safety data for ipamorelin (free base) and ipamorelin acetate administered by the nominator proposed SC ROA" (FDA). mitigate side effect
• General safety: Two deaths occurred in the intravenous clinical program, relatedness undetermined (FDA). Not evidence of causation — but part of the record, and not usually mentioned alongside "well tolerated." mitigate side effect
• General safety: Combination use compounds the unknowns. No stack containing ipamorelin has been tested against its components in any species. mitigate side effect
• General safety: Athletes and service members face strict liability. See — three athletes have been sanctioned in cases naming ipamorelin, two on possession and admission rather than a positive test. mitigate side effect
• The physician conversation: What is the actual goal — sleep, body composition, recovery, "anti-aging" — with a measurable definition and a date by which it should have happened? mitigate side effect
• The physician conversation: Has a growth hormone axis problem ever actually been diagnosed? (Ipamorelin was evaluated by FDA for GH deficiency, a condition with approved diagnostics and approved treatments.) mitigate side effect
• The physician conversation: What are the baseline fasting glucose, HbA1c and potassium — before anything starts, not after? mitigate side effect
• The physician conversation: What is the personal and family history of diabetes or glucose intolerance? ('s only ipamorelin-specific watch marker.) mitigate side effect
• The physician conversation: What else is being taken, including anything from a non-pharmacy source? mitigate side effect
• The physician conversation: Is there any competitive sport, collegiate, professional or military testing obligation? (.) mitigate side effect
• The physician conversation: What is the plan for stopping, and what is expected to happen then? (Nobody has studied this.) mitigate side effect

Measuring it

Retest IGF-1 — Baseline, then on a clinician-set schedule — no guideline sets an IGF-1 interval for this agent, and the rhGH cadence is not borrowed..

• IGF-1 baseline
• IGF-1 on cycle
• Fasting glucose baseline
• Fasting glucose on cycle
• HbA1c baseline
• HbA1c quarterly

How biomarkers respond

• Fasting glucose May deteriorate · Up to 7–10 days of twice-daily IV dosing — Up — hyperglycemia reported as an AE — Trial-reported, ipamorelin-specific (FDA's review itemizes it; the published paper reports only aggregate AE rates) Trial-reported

Safety

• injection-site reactions
• water retention

Interactions

• CJC-1295 — Named beneficial pair — the GHRH-analog + ghrelin-mimetic combination produces a stronger, still-pulsatile GH release than either alone. synergistic

Stacking & alternatives

• Complements CJC-1295 — GHRH analogue. The canonical marketed partner, not a substitute — the pairing exists precisely because the mechanisms differ
• Escalation from MK-677 (Ibutamoren) — Same receptor, orally active, long-acting, with multi-month IGF-1 and body-composition trials ipamorelin has never had. Voted down for 503A at the same 2024-10-29 meeting (minutes)
• Alternative to GHRP-2 — The hexapeptide GHRPs ipamorelin was built to replace. Its entire claim over them is
• Alternative to GHRP-6 — The hexapeptide GHRPs ipamorelin was built to replace. Its entire claim over them is
• Alternative to Hexarelin — The hexapeptide GHRPs ipamorelin was built to replace. Its entire claim over them is

• Tesamorelin
• Sermorelin
• CJC-1295

Access & cost

Legally unsettled. Access, where it exists at all, runs through a physician — not a consumer purchase. See the status note above.

No lawful channel to price. As of 2026-08-28 there is no lawful US route to obtain ipamorelin for human use: not FDA-approved, no USP or NF monograph, not a component of an approved drug, voted down 0–12 for the 503A bulks list, and its acetate form in Category 2 of FDA's 503B interim policy (FDA briefing document; PCAC minutes; FDA bulk substances page). There is therefore no legitimate compounding-pharmacy, telehealth or brand price to report. A gray market nonetheless exists and has been characterised in the published literature: FDA's evaluation records that ipamorelin formulations "are increasingly being marketed by medical spas and wellness clinics," and an independent analysis of thousands of consumer-directed peptide test results — ipamorelin among the compounds included — documents a substantial direct-to-consumer supply operating outside regulatory oversight (FDA; Mendias & Awan).

Questions

Does ipamorelin actually work?

It reliably does one narrow thing: a single intravenous dose produces one pulse of growth hormone in healthy men (PMID 10496658). Whether that pulse produces any outcome a person would care about — more muscle, less fat, better sleep, faster healing — has never been tested in a human being. The only placebo-controlled efficacy trial ever published tested it for postoperative ileus and it did not beat placebo (DOI 10.1007/s00384-014-2030-8).

Does ipamorelin raise cortisol or prolactin?

Nobody knows, in humans. The "selective, no cortisol or prolactin" claim comes from a 1998 experiment in pigs, and the human trials that exist never measured cortisol, ACTH or prolactin at all (DOI 10.1530/eje.0.1390552; PMID 10496658). See.

Does ipamorelin cause weight loss or weight gain?

No human study has measured either. In mice, ipamorelin increased relative body fat — including in GH-deficient mice, so independently of GH (PMID 11162489). In ferrets it prevented chemotherapy-induced weight loss (DOI 10.1016/j.physbeh.2024.114644). Its receptor is the ghrelin receptor, whose core physiological job is stimulating appetite. Mechanism and animal data both point toward weight gain, not loss.

Oral or nasal vs. injectable — which one works?

None has been compared to another in a human efficacy trial. Only one non-intravenous human exposure has ever been published: a single volunteer given ipamorelin intranasally in a doping-control study designed to generate urinary metabolites, not to measure any effect (PMID 25869809). Rat pharmacokinetics estimated nasal bioavailability at roughly 20% — the lowest of the peptides compared (DOI 10.1080/004982598238976). Oral is the weakest case of all: Novo Nordisk's response to ipamorelin's poor oral properties was to build a different molecule, NN703, specifically to be orally active (DOI 10.1530/eje.0.1410180). FDA records ipamorelin being marketed in "injectable, nasal, and oral formulations" by medical spas and wellness clinics (FDA) — a description of the market, not evidence any of them work.

Is ipamorelin safe?

Not established. The 2014 trial found a week of twice-daily IV dosing about as well tolerated as saline in post-surgical patients — real, but narrow. FDA's review of that program lists adverse events including hypokalemia, insomnia, hyperglycemia, nausea, vomiting, abdominal distention and two deaths of unclear relatedness, notes potential behavioral-reinforcing (addiction) properties from ghrelin-receptor agonism and potential effects on reproductive health and pregnancy, and states there are no safety data for the subcutaneous route at all (FDA).

Is ipamorelin banned in sports?

Yes, at all times, in and out of competition — named explicitly on the WADA Prohibited List under S2.2.4 (2026 Prohibited List). It is detectable in urine and athletes have been sanctioned for it.

How does it compare to MK-677?

Same receptor, very different evidence base — the most common source of confused expectations. MK-677 (ibutamoren) is an orally active, long-acting GHS-R1a agonist with multi-month randomized human trials measuring IGF-1, body composition and metabolic endpoints. Ipamorelin has none of that. Biomarker data reported for MK-677 — sustained IGF-1 elevation, fat-free mass change, and the associated rises in fasting glucose and falls in insulin sensitivity — belongs to MK-677 and has not been shown for ipamorelin. Both were voted down for the 503A bulks list at the same 2024-10-29 PCAC meeting (minutes). See. ---

Citations

• mechanistic and small-study human GH/IGF-1 response data mechanistic