Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption.

Johansen PB, Hansen KT, Andersen JV, Johansen NL

Xenobiotica; the fate of foreign compounds in biological systems1 Nov 1998Cited by 3 (Europe PMC)

PMID9879640DOI10.1080/004982598238976PepBankPUB-09879640

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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study11

9 results from studies that gave the peptide. No result from this study comes from people.

01AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, plasma concentrations of the peptides, including ipamorelin, declined biexponentially after an i.v. bolus injection.
In plain wordsIn rats, blood levels of the peptides fell in two phases after an injection into a vein.
Peptide
Ipamorelin
Outcome
Not applicablePlasma concentration decline after i.v. bolus
Study
ratn: not reported in source
Male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Source sentences
Summary
Following i.v. bolus injection, plasma concentrations of the peptides declined biexponentially.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964001
02AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, ipamorelin had a systemic plasma clearance 5-fold lower than that of GHRP-6.
In plain wordsIn rats, ipamorelin was cleared from the blood five times more slowly than GHRP-6.
Peptide
Ipamorelin
Outcome
DecreaseSystemic plasma clearance
Study
ratn: not reported in source
Male rat
Comparator
GHRP-6
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Source sentences
Summary
Ipamorelin differed markedly from the other peptides investigated, demonstrating a systemic plasma clearance 5-fold lower than that of GHRP-6.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964002
03AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, ipamorelin was mainly excreted in the urine, whereas GHRP-6 was predominantly excreted in the bile.
In plain wordsIn rats, ipamorelin left the body mainly in urine, while GHRP-6 left mainly in bile.
Peptide
Ipamorelin
Outcome
Not applicableRoute of excretion
Study
ratn: not reported in source
Male rat
Comparator
GHRP-6
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Source sentences
Summary
Ipamorelin was mainly excreted in the urine, whereas GHRP-6 was predominantly excreted in the bile.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964003
04AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, 60-80% of the administered dose of ipamorelin and two NNC peptides was recovered from bile and urine as intact peptide.
In plain wordsIn rats, most of the dose of ipamorelin and two related peptides left the body as intact peptide.
Peptide
Ipamorelin
Outcome
Not applicableRecovery of intact peptide from bile and urine
Study
ratn: not reported in source
Male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Measurements
Intact peptide recovered from bile and urine
60 to 80%
ipamorelin and two NNC peptides
Source sentences
Summary
Ipamorelin and the two NNC peptides were moderately resistant towards metabolism as 60-80% of the administered dose could be recovered from bile and urine as intact peptide.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964004
05AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, the bioavailability of ipamorelin after intranasal application was estimated at approximately 20%.
In plain wordsIn rats, about 20% of an intranasal ipamorelin dose reached the blood.
Peptide
Ipamorelin
Outcome
Not applicableIntranasal bioavailability
Study
ratn: not reported in source
Male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intranasalAs given in this study (rat).
Measurements
Bioavailability
≈ 20%
intranasal ipamorelin
Source sentences
Summary
After intranasal application, the bioavailability of ipamorelin was estimated at approximately 20%.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964005
06AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, GHRP‑6 had a systemic plasma clearance 5-fold higher than ipamorelin after intravenous bolus injection.
In plain wordsIn male rats, the body cleared GHRP‑6 from the blood about 5 times faster than ipamorelin.
Peptide
GHRP-6
Outcome
IncreaseSystemic plasma clearance versus ipamorelin
Study
ratn: not reported in source
male rat
Comparator
Ipamorelin
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Source sentences
Summary
Ipamorelin differed markedly from the other peptides investigated, demonstrating a systemic plasma clearance 5-fold lower than that of GHRP-6.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964006
07AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, GHRP‑6 was predominantly excreted in the bile, whereas ipamorelin was mainly excreted in the urine.
In plain wordsIn male rats, GHRP‑6 left the body mostly through bile, while ipamorelin left mostly through urine.
Peptide
GHRP-6
Outcome
Not applicableRoute of excretion
Study
ratn: not reported in source
male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intravenous bolusAs given in this study (rat).
Source sentences
Summary
Ipamorelin was mainly excreted in the urine, whereas GHRP-6 was predominantly excreted in the bile.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964007
08AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, the nasal absorption of GHRP‑6 was somewhat lower than the bioavailability of approximately 50% for GHRP-2 and the NNC peptides.
In plain wordsIn male rats, GHRP‑6 was absorbed through the nose, somewhat less than GHRP-2 and two other test peptides.
Peptide
GHRP-6
Outcome
Not applicableIntranasal bioavailability
Study
ratn: not reported in source
male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intranasalAs given in this study (rat).
Source sentences
Summary
Higher bioavailabilities of approximately 50% were determined for NNC 26-0235, NNC 26-0194 and GHRP-2, whereas the nasal absorption of GHRP-6 was somewhat lower.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964008
09AnimalAnimal study (in vivo)Pharmacokinetics
In male rats, the intranasal bioavailability of GHRP‑2 was approximately 50%.
In plain wordsIn male rats, about 50% of a nasal dose of GHRP‑2 reached the bloodstream.
Peptide
GHRP-2
Outcome
Not applicableIntranasal bioavailability
Study
ratn: not reported in source
Male rat
Outcome group
Pharmacokinetics · Pharmacology
Studied dose
Dose not stated · intranasalAs given in this study (rat).
Measurements
bioavailability
≈ 50%
GHRP-2, intranasal
Source sentences
Summary
Higher bioavailabilities of approximately 50% were determined for NNC 26-0235, NNC 26-0194 and GHRP-2
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
Report a problemFND-0987964010

Studies that did not test the peptide alone2

In this study, the peptide was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking the peptide.

10AnimalNot a test of GHRP-6 aloneAnimal study (in vivo)Pharmacokinetics
In male rats, plasma concentrations of the five peptides compared, GHRP‑6 among them, declined biexponentially after intravenous bolus injection.
In plain wordsIn male rats, blood levels of all compared peptides, including GHRP‑6, fell in two phases after an injection into a vein.
Peptide
GHRP-6
Outcome
Not applicablePlasma concentration decline after i.v. bolus, all peptides
Study
ratn: not reported in source
male rat
Outcome group
Pharmacokinetics · Pharmacology
Source sentences
Summary
Following i.v. bolus injection, plasma concentrations of the peptides declined biexponentially.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
In this study, GHRP-6 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-6.
Report a problemFND-0987964009
11AnimalNot a test of GHRP-2 aloneAnimal study (in vivo)Pharmacokinetics
In male rats after an i.v. bolus, plasma concentrations of the five peptides tested, including GHRP‑2, declined biexponentially.
In plain wordsIn male rats, blood levels of the five tested peptides, GHRP‑2 among them, fell in two phases after an injection.
Peptide
GHRP-2
Outcome
Not applicablePlasma concentration decline after i.v. bolus
Study
ratn: not reported in source
Male rat
Outcome group
Pharmacokinetics · Pharmacology
Source sentences
Summary
Following i.v. bolus injection, plasma concentrations of the peptides declined biexponentially.
1 context sentence(design, population, supporting numbers)
Summary · context
The pharmacokinetics of three new peptidyl growth hormone secretagogues, ipamorelin (NNC 26-0161), NNC 26-0194 and NNC 26-0235, were compared with two well-known hexapeptides, GHRP-2 and GHRP-6, in the male rat following different routes of administration.
In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.
Report a problemFND-0987964011

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Versions 22 to 45Current
28 Oct 2026, 02:02 UTC
The same notice was added 24 times, first on 13 Oct 2026, 21:43 UTC. The status did not change between them.
Study results updated
Version 21
13 Oct 2026, 16:31 UTC
Study data updated · source update from Europe PMC
Versions 3 to 20
13 Oct 2026, 14:22 UTC
The same notice was added 18 times, first on 9 Oct 2026, 18:17 UTC. The status did not change between them.
Study results updated
Version 2
9 Oct 2026, 03:13 UTC
Study data updated · source update from Europe PMC
Version 1
9 Oct 2026, 03:13 UTC
First added · source update from Europe PMC

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