BlessUp Peptide Library · Growth & Recovery

The GH secretagogue class, decoded

Sermorelin, CJC-1295, ipamorelin, the GHRPs, tesamorelin, MK-677. Nine ways to nudge your own growth hormone, pulling one of two levers.

They amplify the pulse you already make. That is the whole point, and the honest catch.

2
levers the whole class pulls: the GHRH switch and the ghrelin (GHRP) switch
-18%
visceral fat on tesamorelin at a year, the one member with real trial evidence
1
member is FDA-approved. The rest are research compounds with far thinner data

Tesamorelin visceral-fat figure: Falutz 2010, J Acquir Immune Defic Syndr (404-patient trial). Full citations at the end.

You have seen the menu: sermorelin, CJC-1295, ipamorelin, GHRP-2, GHRP-6, hexarelin, tesamorelin, and the oral one, MK-677. Nine names, all promising more growth hormone, and it is easy to read them as nine flavors of the same thing.

Here is the honest version. Every one of these is a secretagogue: it tells your own pituitary to release more of your own growth hormone, in your own natural rhythm, instead of injecting synthetic HGH from outside. That is the key difference from HGH, and it is a genuine advantage, because it keeps your body's feedback brake and your natural nightly pulse intact. Underneath, the whole class pulls just two levers, and most of these compounds are simply different ways of pulling one or the other. What actually changes from one to the next is which lever, how hard, how cleanly, and, most importantly, how much real human evidence stands behind it. We do honest, not hype, so let us take it slowly.

Read this first

This is education, not medical advice, and it does not replace your own clinician or your own labs. Of this class, only tesamorelin is FDA-approved (for a specific medical condition); sermorelin was formerly approved and withdrawn for commercial reasons; the rest are research peptides, and MK-677 is an investigational compound never brought to market. Every one raises IGF-1, which carries real contraindications covered below. Any dose named here is an example for discussion, never a prescription.

90-second self-check

Are you cleared to explore this class, and which lever fits?

This flags the hard stops that mean this class is not for you, and if you are clear, it points toward the kind of secretagogue that matches your goal. It is education, not a diagnosis or a recommendation to use anything.

GH secretagogue readiness and fit

Answer honestly. Nothing is stored, and no one sees it but you.

First, the hard stops. Do any of these apply to you? (tap all that are true)

What are you actually weighing this class for?

Any of these in your picture? (tap all that apply)

Is the foundation actually in place? (tap all that apply)

This reflection is education only, not a diagnosis or a recommendation to use any compound. Talk to a licensed provider about your own history and goals.

The basics

Two switches, one readout

Your pituitary releases growth hormone in pulses, mostly at night in deep sleep, and the size of those pulses is set by two opposing signals: GHRH (growth-hormone-releasing hormone, the accelerator) and somatostatin (the brake). Downstream, each GH pulse tells the liver to make IGF-1, which carries most of the actual recovery, body-composition, and anabolic effect and lingers for hours. So the whole class is really about one thing: producing a bigger, well-timed GH pulse, then reading it out as IGF-1.

There are exactly two ways in, which is why there are two families:

  • GHRH analogs press the accelerator directly. They mimic GHRH and drive the pituitary to build and release GH. Members: sermorelin, CJC-1295 (with and without DAC), tesamorelin.
  • Ghrelin agonists (GHRPs) work a different receptor entirely, and do two things at once: they trigger release AND they lift somatostatin, the brake. Members: ipamorelin, GHRP-2, GHRP-6, hexarelin, and the oral non-peptide MK-677.
CompoundFamilyHalf-lifeRouteThe differentiator
SermorelinGHRH~12 minSubQGentle, short, the classic starter
CJC-1295 (no-DAC)GHRH~30 minSubQShort clean pulse; the GHRH half of the blend
CJC-1295 (DAC)GHRH~6-8 daysSubQWeek-long steady bleed; blunts the pulse; pin alone
TesamorelinGHRH~26 minSubQThe only FDA-approved one; real trial data
IpamorelinGHRP~2 hrSubQCleanest: little hunger, cortisol, or prolactin
GHRP-2GHRP~30 minSubQPotent, but appetite and some cortisol/prolactin
GHRP-6GHRP~20 minSubQStrongest hunger of any GHRP
HexarelinGHRP~1 hrSubQMost potent, but desensitizes fastest
MK-677Ghrelin~4-6 hrOralOral convenience; water, hunger, higher glucose

Half-lives are approximate, from the OnePin compound reference. Notice the range: from about 12 minutes (sermorelin) to 6 to 8 days (CJC-1295 with DAC). That single number explains most of how each one behaves.

The honest half-truth you will hear

"Secretagogues are just a safer HGH." Half true. They ARE gentler than injecting synthetic HGH, because they keep your own feedback brake and natural pulse instead of overriding them. But gentler is not the same as proven. Outside tesamorelin, the human outcome evidence for this class is thin, the mechanism is far better established than the results, and every one of them still raises IGF-1, with all the cautions that carries.

The part the marketing flips

The evidence ladder is not the popularity ladder

These are sold as if they are equally established. They are not. Here is an honest read of how much real human evidence sits behind each, separate from how good the mechanism looks or how popular it is. Longer bars mean deeper, more human data, not "works better for you."

Depth of human evidence, by compound

A judgment read of the literature. Tesamorelin is the clear outlier; most of the class is mechanism plus thin outcomes.

Tesamorelin
Approved, real RCTs
MK-677
A 2-year human trial
CJC-1295
PK only, no outcome trial
Sermorelin
Older approved-use data
Ipamorelin / GHRPs
Mechanism, little human outcome data

Synthesized from Falutz 2010/2008 (tesamorelin), Nass 2008 (MK-677), Teichman 2006 (CJC-1295), and the GHRP mechanism literature (Raun 1998, Cordido 1993). Full citations at the end.

The pattern to hold onto: the compound with the most human data (tesamorelin) is not the one the internet talks about most, and the popular pulse-stack (CJC-1295 plus ipamorelin) rests on a strong mechanism and dose-ranging pharmacology, not on a body-composition outcome trial. That gap is the whole honest story of this class.

The number that explains the behavior

Pulse versus bleed

The single most useful number here is half-life, because it decides whether a compound gives you a clean, natural-shaped pulse that clears in hours, or a continuous, days-long bleed of GH that flattens your rhythm. Most of this class is deliberately short, to protect the pulse. One (CJC-1295 with DAC) is deliberately long, for convenience, at the cost of that pulse.

Approximate half-life (log-ish scale, for shape)

Short = a clean pulse that protects your rhythm. Long = a steady bleed and weekly dosing, but a blunted pulse.

Sermorelin (~12 min)
pulse
CJC no-DAC (~30 min)
pulse
Ipamorelin (~2 hr)
pulse
MK-677 (~4-6 hr)
daily, sustained
CJC-1295 DAC (~6-8 days)
continuous bleed

Approximate half-lives from the OnePin compound reference and CJC-1295 pharmacokinetics (Teichman 2006, JCEM). Bar widths are shaped for readability, not linear.

Under the hood

How a bigger pulse actually happens

01

Prime the accelerator

A GHRH analog binds the GHRH receptor on the pituitary and drives it to build and release stored growth hormone, setting the size of the pulse.

02

Release and lift the brake

A GHRP hits a separate receptor: it triggers release AND lowers somatostatin, the body's natural GH brake. Pressing the gas while easing the brake.

03

Read it out as IGF-1

The GH pulse reaches the liver, which makes IGF-1. That is the messenger that carries most of the recovery and body-composition effect, and it lingers for hours.

Because the two families work through different receptors, using one of each at the same time does more than add up. According to PubMed, combining a GHRH signal with a GHRP produced a synergistic, much larger GH discharge than either alone (Cordido 1993 doi:10.1210/jcem.76.4.8473389). That is the entire logic behind the classic pairing below.

Why the classic stack is a stack

One GHRH plus one GHRP, never two of the same

The famous pairing, CJC-1295 (no-DAC) plus ipamorelin, is not two versions of one thing. It is one lever from each family: the GHRH side sets the pulse height, the GHRP side triggers it and lifts the brake. Hit both receptors at once and the pulse is bigger and cleaner than either produces alone. The same logic pairs tesamorelin with ipamorelin.

The one rule that prevents most mistakes

Never combine two GHRH agents (sermorelin, CJC, tesamorelin all hit the same receptor, so stacking them is redundant and just desensitizes it), and do not double up GHRPs either (one ghrelin receptor, and stacking reintroduces the hunger, cortisol, and prolactin you were avoiding). A GHRH's partner is a GHRP, not another GHRH. And CJC-1295 with DAC is pinned by itself.

The members, with honest pros and cons

Each one, side by side

Same goal, two families, and honestly, very different levels of proof. Tags show the family: GHRH (the accelerator), GHRP / ghrelin (release plus un-brake), or oral.

Sermorelin

GHRH · the starter

The first GHRH analog, a fragment of your own GHRH. Gentle, short-acting, and the classic entry point.

Pros
  • Physiologic and mild: a short, natural-shaped pulse that preserves your rhythm
  • Formerly FDA-approved, with a long, well-characterized safety record
  • A sensible, low-drama first GHRH to pair with a GHRP
Cons
  • Shortest-acting and least potent of the GHRH analogs
  • Largely superseded by CJC-1295 no-DAC and tesamorelin in modern protocols
  • No exogenous stabilization, so it breaks down fast

Honest read: the gentle on-ramp. Typically dosed at night, fasted, paired with a GHRP. Half-life about 12 minutes.

CJC-1295 (no-DAC vs DAC)

GHRH · two versions

The same GHRH molecule in two very different kinetics. No-DAC gives a short clean pulse; the DAC version binds albumin and lasts a week.

Pros
  • No-DAC (Mod GRF 1-29): a short, clean pulse that protects your rhythm, the GHRH half of the classic blend
  • DAC: one shot a week, sustained GH and IGF-1 for days, proven in dose-ranging pharmacology
  • Human data confirms a real, dose-dependent GH and IGF-1 rise
Cons
  • DAC's week-long "bleed" blunts the natural pulse and must be pinned alone
  • Which version is better for body composition is genuinely debated
  • Human evidence is pharmacology, not a body-composition outcome trial

Honest read: no-DAC for pulse purists, DAC for convenience. Half-life about 30 minutes (no-DAC) versus 6 to 8 days (DAC).

Tesamorelin

GHRH · the evidenced one

A stabilized GHRH analog and the only FDA-approved member of this class. The one with real trial data.

Pros
  • The strongest human evidence of the class: about 18% visceral-fat reduction over a year, in a 400-plus-patient trial
  • FDA-approved (for HIV-associated visceral fat), with a defined dose and safety profile
  • Reduced visceral fat without worsening glucose in its trials
Cons
  • The gold-standard data is in one specific medical condition; general use is off-label extrapolation
  • Anti-drug antibodies develop in about half of users by 26 weeks (no apparent efficacy loss)
  • The visceral-fat benefit reverses once you stop

Honest read: the choice when you value real evidence and accept your goal may be off-label. Daily, evening, fasted; 2 mg is the studied dose.

Ipamorelin

GHRP · the clean one

A selective ghrelin-receptor agonist and the cleanest GHRP. The GHRP leg most people reach for.

Pros
  • The most selective GHRP: little to no hunger, cortisol, or prolactin, even at high doses
  • The default GHRP partner for a GHRH in the classic pulse stack
  • Well-characterized receptor selectivity
Cons
  • Rarely the whole answer alone; it is a partner, not a solo act
  • Human outcome data for the goals people chase (recomp, sleep) is light
  • Above roughly 300 mcg per shot the receptor is saturated, so more dose just buys side effects

Honest read: the clean GHRP to pair with a GHRH. Selectivity is well established; the payoffs are mostly extrapolated. Half-life about 2 hours.

GHRP-2 and GHRP-6

GHRP · potent, less clean

Older, more potent ghrelin agonists that trade selectivity for punch, and bring appetite and stress hormones along.

Pros
  • Stronger raw GH release than ipamorelin
  • GHRP-6's dramatic hunger is genuinely useful when appetite is the goal (wasting, hard-gainers)
  • Long history of use and diagnostic study
Cons
  • Both raise appetite (GHRP-6 dramatically), plus cortisol and prolactin
  • Not suitable for anyone managing weight or sensitive to cortisol (anxiety, poor sleep)
  • The extra potency comes with the exact side effects ipamorelin exists to avoid

Honest read: more GH, more baggage. GHRP-2 for potency-over-cleanliness; GHRP-6 when hunger is the point. Both short-acting, dosed fasted.

Hexarelin

GHRP · the strong, short one

The most potent GHRP per dose, with a unique heart-protective action, but it desensitizes the receptor fastest.

Pros
  • Highest GH release per dose of any GHRP
  • A genuinely interesting, GH-independent cardioprotective signal in the research
  • Useful for short, intensive blocks
Cons
  • Desensitizes the receptor fastest, so it needs short cycles (a few weeks) and stops working if run continuously
  • Raises cortisol and prolactin more than ipamorelin
  • Not a set-and-forget compound

Honest read: maximum punch for a short block, not a daily driver. Cycle it deliberately. Half-life about 1 hour.

MK-677 (ibutamoren)

Oral · the convenient one

The only oral, non-peptide member. A ghrelin mimetic in a pill that raises GH and IGF-1 with daily dosing and no needles.

Pros
  • Oral and convenient; no injections
  • Raises IGF-1 to youthful levels and increased fat-free mass in a 2-year human trial
  • Consistently reported to improve deep and REM sleep, and sustains GH without pituitary burnout
Cons
  • Raises fasting glucose and worsens insulin sensitivity, the metabolic catch that ended its development
  • Water retention and a real increase in appetite (works against a fat-loss goal)
  • Never approved; runs directly counter to a GLP-1 or any glucose-sensitive plan

Honest read: real convenience and real IGF-1 and sleep data, with a real glucose price. Watch fasting glucose and HbA1c. Half-life about 4 to 6 hours; dosed at night.

What they realistically do

The honest reach, and its edge

The reliable, measurable common effect is an IGF-1 rise, and the compounds that raise it deliver the recovery-and-body-composition family of benefits people are after: better deep sleep (especially MK-677), improved fat-free mass over time, and support for connective-tissue and bone remodeling. The one place with genuinely strong human numbers is tesamorelin's visceral-fat reduction, and MK-677 has a real 2-year trial behind its IGF-1 and lean-mass effects.

Now the edge of the map, honestly. Outside those two, the recovery, recomposition, and anti-aging payoffs for the injectable GHRPs are mechanistic extrapolation, not outcome trials. And none of these builds muscle or burns fat for you. They amplify a GH signal that supports the work; the protein and the training do the work. A secretagogue on a poor foundation is an expensive way to raise a lab value.

Where the honest line sits

The mechanism is real and elegant. Tesamorelin has approved-level evidence. MK-677 has a long human trial. Everything else is a strong story with light human proof. That is not a reason to dismiss the class, it is a reason to be honest about which rung of the evidence ladder you are actually standing on.

The most important section here

The hard stops and the real cautions

This matters more than any IGF-1 number. Everything in this class raises GH and IGF-1, and IGF-1 is a growth signal, which is exactly why some of these lines are firm.

1

Active cancer, or a history of cancer

IGF-1 is a proliferation signal, so raising it in someone with active or prior malignancy is the central hard stop for the whole class. This is not a self-clear item: anyone with a cancer history needs a provider before considering any of these compounds.

2

Diabetes, insulin resistance, and glucose

Growth hormone is diabetogenic: it raises blood sugar and can worsen insulin sensitivity. MK-677 does this most reliably (higher fasting glucose and HbA1c in trials), and continuous elevation pushes it hardest. Anyone with diabetes, prediabetes, or insulin resistance needs glucose monitoring and a provider.

3

Diabetic eye disease (retinopathy)

Active proliferative diabetic retinopathy is a recognized caution with growth-hormone therapy, because GH and IGF-1 can drive the abnormal vessel growth involved. Flag any diabetic eye disease before starting.

4

Pregnancy and breastfeeding

This class is not for use in pregnancy or breastfeeding. Clear that first.

5

Uncontrolled thyroid, cortisol, or blood pressure

The less-selective GHRPs (GHRP-2, GHRP-6, hexarelin) raise cortisol and prolactin, which can worsen anxiety, sleep, and a poorly-controlled cortisol or thyroid picture. Get those managed first, and favor the cleaner ipamorelin if you proceed.

6

Fluid-retention and nerve symptoms

These raise GH-driven water retention, which can cause carpal-tunnel-like numbness and joint aches. If you already have significant carpal tunnel or joint issues, go low and slow, and stop if symptoms flare.

The one rule under all of it

Start at the lowest effective lever, respect the saturation ceilings, cycle it, and involve a provider, especially if you are considering the investigational members or have any cancer, glucose, or eye-disease history. The IGF-1 you are raising is the whole benefit and the whole risk.

Put it together

How to think about choosing, honestly

First question

Are you cleared at all?

  • No active or prior cancer
  • Glucose, insulin sensitivity, and any diabetic eye disease handled with a provider
  • Not pregnant or breastfeeding; cortisol and thyroid controlled
  • If a hard stop is present, this class is not the tool, full stop

Second question

Which lever fits the goal?

  • Gentle start: sermorelin, or ipamorelin as the clean GHRP
  • The popular pulse stack: CJC-1295 no-DAC plus ipamorelin
  • Real evidence: tesamorelin (plus ipamorelin), accepting off-label use
  • No needles: MK-677, accepting the glucose and appetite trade

The move most people skip

Fix the foundation first, then pick the lowest lever that fits. One GHRH plus one GHRP, dosed at night and fasted, beats a big multi-compound stack for almost everyone. Matching beats maxing.

The foundation under everything

What actually decides your result

Sleep, first and biggest

Growth hormone is released mostly in deep sleep, so sleep is the single largest natural GH lever you own, and it is the whole reason these are dosed at bedtime, to stack the drug pulse on top of the natural one. Fix short or broken sleep before you spend a dollar on a peptide, or you are amplifying a pulse you are also sabotaging.

Protein and resistance training

The peptide raises the GH and IGF-1 signal; protein and lifting are what that signal acts on. Without them, a higher IGF-1 is just a number. With them, it supports the recovery and body composition you are training for.

Fasted timing, away from carbs

A glucose and insulin spike blunts the GH pulse, so eating (especially carbs) around a pulse-style dose literally costs you the dose. The standard is an empty stomach for about two hours before and thirty minutes after. The long-acting DAC version is the exception.

Hydration, and easy on alcohol

Water retention and mild joint aches are the common early complaints; steady hydration and modest, gradual dosing blunt them. Alcohol near dosing works against the pulse and against sleep.

Cutting through the noise

Support, graded honestly

Solid

Deep sleep, adequate protein, and resistance training

The genuinely supported base of any GH-axis effort. This is what turns a raised IGF-1 into an actual result. Boring, and it works.

Reasonable

Magnesium and glycine for sleep quality

Sensible support for the deep sleep that drives your natural GH pulse. Useful alongside the basics, not a replacement for them.

Unproven

"GH-boosting" amino blends (arginine, ornithine, GABA pills)

Marketed as natural secretagogues. The effect is small, inconsistent, and easily erased by a meal. Mostly money better spent on sleep and protein.

Skip

Running MK-677 alongside a GLP-1 or on an unmonitored glucose

MK-677 raises glucose and insulin resistance; pairing it with a glucose-sensitive plan, or running it without checking fasting glucose, is working directly against yourself.

Turn this into action

Questions to ask yourself

Have I honestly ruled out the hard stops: any cancer history, pregnancy, and active diabetic eye disease?

Is my sleep actually handled, since that is the biggest natural GH lever I own?

Am I choosing one GHRH plus one GHRP, or piling on redundant compounds from the same family?

Do I know which rung of the evidence ladder my chosen compound is on?

If I am considering MK-677, am I set up to monitor fasting glucose?

Bring these to your visit

Questions to ask your provider

Given my history, is any member of this class off the table for me, and which lever fits my goal?

What baseline labs should we check, and how often should we recheck IGF-1 and glucose?

What is a sensible starting dose and cycle length, and when do we stop?

What symptoms should make me stop and call you?

The numbers worth knowing

  • IGF-1: the readout of the whole class, checked at baseline and on therapy to stay in a sensible range.
  • Fasting glucose and HbA1c: because GH is diabetogenic, especially on MK-677 or continuous dosing.
  • Personal and family cancer history: the first screen, because it can take the class off the table entirely.
  • Any diabetic eye disease: flagged before starting.

Stop and get medical help

A few situations are not "go slower," they are "stop and be seen."

  • Any new or growing lump, or a change you are worried could be cancer
  • New or worsening vision changes, especially with diabetes
  • Signs of very high or hard-to-control blood sugar
  • Severe or persistent numbness, tingling, or wrist pain (carpal tunnel)
  • Severe swelling, shortness of breath, or a fast or irregular heartbeat
  • Any severe allergic reaction: swelling of the face or throat, trouble breathing

Mild water retention and a little joint stiffness settle. A new lump, vision change, or a glucose you cannot control are different, and they are provider questions, not push-through-it ones.

The BlessUp take

Amplify your own pulse, and be honest about the proof

The idea here is genuinely good: instead of overriding your body with synthetic HGH, you nudge your own pituitary to pulse a little harder, in your own rhythm, and you keep the feedback brake that keeps the whole system safe. Two levers, the GHRH accelerator and the ghrelin release-and-un-brake, and the smartest use is one of each, dosed at night, on top of real sleep. The variable people skip is evidence depth. Tesamorelin has approved-level trials. MK-677 has a long human study and a real glucose price. The rest is a strong, well-understood mechanism riding on thin human outcomes. None of it builds the body for you. So fix the foundation first, clear the hard stops honestly, pick the lowest lever that fits, respect the ceilings, cycle it, and stand on the evidence level you are actually comfortable with, with a provider. That is not the timid move. It is the strong one.

The evidence

Sources

Human figures are the published results from each compound's key trial, retrieved from PubMed. Only tesamorelin and MK-677 have substantial human outcome trials; the rest of the class rests on pharmacology and mechanism studies. Half-life figures are approximate, from product data and the OnePin compound reference.

  1. Falutz J, Potvin D, Mamputu JC, et al. Effects of tesamorelin in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial. J Acquir Immune Defic Syndr. 2010;53(3):311-322. doi:10.1097/QAI.0b013e3181cbdaff
  2. Falutz J, Allas S, Mamputu JC, et al. Long-term safety and effects of tesamorelin, a growth hormone-releasing factor analogue, in HIV patients with abdominal fat accumulation. AIDS. 2008;22(14):1719-1728. doi:10.1097/QAD.0b013e32830a5058
  3. Nass R, Pezzoli SS, Oliveri MC, et al. Effects of an oral ghrelin mimetic (MK-677) on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-611. doi:10.7326/0003-4819-149-9-200811040-00003
  4. Teichman SL, Neale A, Lawrence B, et al. Prolonged stimulation of growth hormone and IGF-I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006;91(3):799-805. doi:10.1210/jc.2005-1536
  5. Cordido F, Penalva A, Dieguez C, Casanueva FF. Massive growth hormone discharge in obese subjects after the combined administration of GHRH and GHRP-6: evidence for the synergy of the two pathways. J Clin Endocrinol Metab. 1993;76(4):819-823. doi:10.1210/jcem.76.4.8473389
  6. Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561. doi:10.1530/eje.0.1390552

Citations retrieved from PubMed. Injectable GHRPs (ipamorelin, GHRP-2, GHRP-6, hexarelin) and CJC-1295 have strong mechanistic and pharmacologic data but limited human outcome trials; treat their recomposition and anti-aging claims as extrapolation. This report is an honest educational map of the class, not a dosing sheet or a recommendation to use any compound.