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Compounds · Secretagogues & GH axis

Ipamorelin selectivity claims and where they came from

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EK
e.kjeldsenTL2Member10 Dec 2024#1

Ipamorelin selectivity claims and where they came from — setting out what I have, and where I think it stops being reliable.

I have seen LEADER (N Engl J Med, 2016) cited in support of a claim I do not think it supports, twice this month, so I would like to work through what it actually shows.

My reading is that the trial is sound for its own question and is being stretched to answer a different one. I might be wrong about that, which is why this is a topic rather than a correction.

What I would like from this discussion: someone who disagrees with me to say why, with the section of the paper they are relying on.

0 likes 20mo
NR
n.rowntreeTL3Regular20 Dec 2024 · edited#2

Development history is more informative than speculation: ipamorelin was investigated clinically for post-operative ileus and was not taken forward to registration. That it was not brought to market tells you something about the cost-benefit calculation that any amount of forum enthusiasm does not.

20 likes 19mo
RB
r.bakkenTL2 Moderator27 Dec 2024#3

Why this subcategory is stricter about sourcing than most: the evidence base is weaker and that is precisely why documentation quality matters more. A supplier page that clearly identifies the compound and the purity is more valuable for secretagogues than for incretin agonists where the evidence base is stronger.

8 likes 19mo
CW
c.wijnbergTL2Member2 Jan 2025#4

the opening post answers the question as asked. The question underneath it is different.

Secretagogues and glucose tolerance: there is a mechanistic concern that sustained growth hormone elevation might impair glucose tolerance. The clinical relevance of this concern in practice is not well established.

2 likes 19mo
TI
t.ibarraTL2 Moderator7 Jan 2025#5
c.wijnberg, post #4: the opening post answers the question as asked. The question underneath it is different. Secretagogues and glucose tolerance: there is a mechanistic concern that sustained growth hormone elevation might impair glucose tolerance. The clinical relevance of this concern in practice is not well established. Go to post

I read post #3 twice before replying, because I had assumed the opposite.

What a well-designed human trial of a secretagogue would look like: randomised, placebo-controlled, adequate sample size, IGF-1 as primary outcome, muscle and strength as secondary outcomes, adequate follow-up duration. Very few secretagogue trials meet that description.

28 likes in reply to #4 19mo
TN
t.nardoneTL3Regular12 Jan 2025#6
r.bakken, post #3: Why this subcategory is stricter about sourcing than most: the evidence base is weaker and that is precisely why documentation quality matters more. A supplier page that clearly identifies the compound and the purity is more valuable for secretagogues than for incretin agonists where the evidence base is stronger. Go to post

Reading a rodent study on a secretagogue without over-extrapolating: rodent studies can show a mechanism is plausible. They cannot show magnitude of effect in humans or safety profile in humans. That gap is larger for secretagogues than for incretin agonists because the human evidence is thinner.

14 likes in reply to #3 18mo
NA
n.achebeTL2 Moderator17 Jan 2025#7

Ipamorelin selectivity claims originate in preclinical characterisation and are reasonably well supported for what they claim: less effect on cortisol and prolactin than earlier GHRPs. Whether that translates to something clinically meaningful is a different question from whether the selectivity is real.

5 likes 18mo
FE
footnote_entryTL322 Jan 2025#8
SZ
s.zamoraTL2 Moderator27 Jan 2025 · edited#9
c.wijnberg, post #4: the opening post answers the question as asked. The question underneath it is different. Secretagogues and glucose tolerance: there is a mechanistic concern that sustained growth hormone elevation might impair glucose tolerance. The clinical relevance of this concern in practice is not well established. Go to post

Evidence quality in the secretagogue literature is honestly weaker than in the incretin literature. Large randomised controlled trials are rare. Most evidence is mechanistic or from small studies. This is why this subcategory has higher sourcing standards than most.

0 likes in reply to #4 18mo
BW
bac_waterTL2Regular1 Feb 2025#10

Picking up post #7: that is the part I would want checked first.

GHRH analogues versus ghrelin mimetics are often conflated but they are different mechanisms. GHRH analogues (like CJC-1295) cause the pituitary to release growth hormone. Ghrelin mimetics (like GHRPs) act on the ghrelin receptor directly. The effect on growth hormone secretion is similar but the mechanisms are distinct.

0 likes 18mo
MC
m.coelhoTL2 Moderator5 Feb 2025 · edited#11

Picking up post #8: that is the part I would want checked first.

Tesamorelin has an approved indication in HIV-associated lipodystrophy. That is the only compound in this class with a registration-quality evidence base from a proper trial programme. Generalising from that narrow population to healthy adults is a substantial extrapolation.

19 likes 18mo
BS
b.solbergTL2 Moderator9 Feb 2025#12
e.kjeldsen, post #1: Ipamorelin selectivity claims and where they came from — setting out what I have, and where I think it stops being reliable. I have seen LEADER ( N Engl J Med , 2016) cited in support of a claim I do not think it supports, twice this month, so I would like to work through what it actually shows. My reading is that the trial is sound for… Go to post

Pulsatile secretion matters because growth hormone is secreted in pulses, not continuously. A single post-dose growth hormone level is nearly uninterpretable. Assessing this class properly requires serial sampling or an integrated measure like IGF-1, and almost nothing published online does either.

0 likes in reply to #1 18mo
K
KTurkingtonTL3Regular14 Feb 2025#13

IGF-1 as a surrogate: it is a better integrated measure than a spot growth hormone level and it is still a surrogate, with all the caveats that come with surrogates. Stable or rising IGF-1 is not the same as "this is working" in any health-related sense.

0 likes 17mo
SB
s.bergstromTL218 Feb 2025#14
CD
cannula_driftTL3Regular22 Feb 2025#15

Secretagogues and glucose tolerance: there is a mechanistic concern that sustained growth hormone elevation might impair glucose tolerance. The clinical relevance of this concern in practice is not well established.

13 likes 17mo
FN
f.novakTL2 Moderator26 Feb 2025#16
r.bakken, post #3: Why this subcategory is stricter about sourcing than most: the evidence base is weaker and that is precisely why documentation quality matters more. A supplier page that clearly identifies the compound and the purity is more valuable for secretagogues than for incretin agonists where the evidence base is stronger. Go to post

Why this subcategory is stricter about sourcing than most: the evidence base is weaker and that is precisely why documentation quality matters more. A supplier page that clearly identifies the compound and the purity is more valuable for secretagogues than for incretin agonists where the evidence base is stronger.

27 likes in reply to #3 17mo
BR
buffer_reviewTL3Regular2 Mar 2025#17

Development history is more informative than speculation: ipamorelin was investigated clinically for post-operative ileus and was not taken forward to registration. That it was not brought to market tells you something about the cost-benefit calculation that any amount of forum enthusiasm does not.

0 likes 17mo
SV
sa.vogelTL2 Moderator6 Mar 2025#18

Worth separating two things that post #14 runs together.

Evidence quality in the secretagogue literature is honestly weaker than in the incretin literature. Large randomised controlled trials are rare. Most evidence is mechanistic or from small studies. This is why this subcategory has higher sourcing standards than most.

2 likes 17mo
L
LJankowiakTL3Regular10 Mar 2025#19

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

8 likes 17mo
AC
a.cardosoTL2 Moderator14 Mar 2025 · edited#20

Coming back to post #18, because the follow-up matters more than the original answer.

GHRH analogues versus ghrelin mimetics are often conflated but they are different mechanisms. GHRH analogues (like CJC-1295) cause the pituitary to release growth hormone. Ghrelin mimetics (like GHRPs) act on the ghrelin receptor directly. The effect on growth hormone secretion is similar but the mechanisms are distinct.

19 likes 16mo
LD
l.dialloTL2 Moderator18 Mar 2025#21
KTurkington, post #13: IGF-1 as a surrogate: it is a better integrated measure than a spot growth hormone level and it is still a surrogate, with all the caveats that come with surrogates. Stable or rising IGF-1 is not the same as "this is working" in any health-related sense. Go to post

Coming back to post #19, because the follow-up matters more than the original answer.

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

0 likes in reply to #13 16mo
CI
c.inglethorpeTL3Regular21 Mar 2025#22

CJC-1295 with and without DAC: the version with a drug affinity complex binds albumin covalently and persists for days. The version without it does not persist. Supplier labelling frequently does not distinguish them clearly, so confirming which you have is important.

23 likes 16mo
HB
h.bhattacharyaTL2 Moderator25 Mar 2025#23

What a well-designed human trial of a secretagogue would look like: randomised, placebo-controlled, adequate sample size, IGF-1 as primary outcome, muscle and strength as secondary outcomes, adequate follow-up duration. Very few secretagogue trials meet that description.

6 likes 16mo
C
CSagredoTL3Regular29 Mar 2025 · edited#24

post #23 answers the question as asked. The question underneath it is different.

Reading a rodent study on a secretagogue without over-extrapolating: rodent studies can show a mechanism is plausible. They cannot show magnitude of effect in humans or safety profile in humans. That gap is larger for secretagogues than for incretin agonists because the human evidence is thinner.

1 like 16mo
BV
b.vestergaardTL2 Moderator1 Apr 2025#25
sa.vogel, post #18: Worth separating two things that post #14 runs together. Evidence quality in the secretagogue literature is honestly weaker than in the incretin literature. Large randomised controlled trials are rare. Most evidence is mechanistic or from small studies. This is why this subcategory has higher sourcing standards than most. Go to post

Tesamorelin has an approved indication in HIV-associated lipodystrophy. That is the only compound in this class with a registration-quality evidence base from a proper trial programme. Generalising from that narrow population to healthy adults is a substantial extrapolation.

0 likes in reply to #18 16mo
B
BGiordanoTL2Member5 Apr 2025#26
KTurkington, post #13: IGF-1 as a surrogate: it is a better integrated measure than a spot growth hormone level and it is still a surrogate, with all the caveats that come with surrogates. Stable or rising IGF-1 is not the same as "this is working" in any health-related sense. Go to post

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

31 likes in reply to #13 16mo
HA
h.amankwahTL29 Apr 2025#27
CD
cannula_driftTL3Regular12 Apr 2025#28

post #27 is right about the mechanism and I think understates the practical bit.

IGF-1 as a surrogate: it is a better integrated measure than a spot growth hormone level and it is still a surrogate, with all the caveats that come with surrogates. Stable or rising IGF-1 is not the same as "this is working" in any health-related sense.

3 likes 16mo
PL
p.lindqvistTL2 Moderator16 Apr 2025#29

Ipamorelin selectivity claims originate in preclinical characterisation and are reasonably well supported for what they claim: less effect on cortisol and prolactin than earlier GHRPs. Whether that translates to something clinically meaningful is a different question from whether the selectivity is real.

1 like 15mo
CE
crossover_entryTL3Regular19 Apr 2025#30
t.nardone, post #6: Reading a rodent study on a secretagogue without over-extrapolating: rodent studies can show a mechanism is plausible. They cannot show magnitude of effect in humans or safety profile in humans. That gap is larger for secretagogues than for incretin agonists because the human evidence is thinner. Go to post

GHRH analogues versus ghrelin mimetics are often conflated but they are different mechanisms. GHRH analogues (like CJC-1295) cause the pituitary to release growth hormone. Ghrelin mimetics (like GHRPs) act on the ghrelin receptor directly. The effect on growth hormone secretion is similar but the mechanisms are distinct.

0 likes in reply to #6 15mo