GHRH (1-29)

Name: GHRH (1-29) — Peptide Information
Creator: Michael Carroll

The 29-amino-acid fragment of growth hormone-releasing hormone, and the shortest piece of it with full activity.

Approved in 1997 as Geref for growth failure in children with growth hormone deficiency and discontinued in 2008; the one controlled trial in older adults tested a modified version of the molecule, not this one [1][5][7].

Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards

Growth HormoneHuman trials in children; one 19-person adult trial of a modified analogue

Suggested dose

10 mcg/kg/day – 30 mcg/kg/day

Once daily at bedtime

~10-20 minutesHalf-life

Subcutaneous: moderate; Intranasal: 3-5%Bioavailability

3357.9 g/molMolecular weight

Human trials in children; one 19-person adult trial of a modified analogueEvidence level

Compound profile

Scientific & efficacy data

Growth Hormone

Peptide profile

Growth and Development9.5

Body Composition8.5

Performance and Recovery8.0

Human trials in children; one 19-person adult trial of a modified analogue

GHRH (1-29)

30 mcg/kg/day · Once daily at bedtime

Molecular formula

C₁₄₉H₂₄₆N₄₄O₄₂S

Mol. weight: 3357.9 g/mol
CAS number: 86168-78-7
PubChem: 16132413
Developed · 1982: Roger Guillemin
Salk Institute

Amino acid sequence

Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2

Growth and Development

The one thing this molecule has strong evidence for. In 110 prepubertal children with growth hormone deficiency, 30 mcg/kg nightly raised height velocity from 4.1 to 8.0 cm/year at 6 months and 7.2 cm/year at 12 months, with 74% judged good responders [5]. Growth hormone itself produced larger gains at the same dose per kilogram [1].

Body Composition

Much weaker than usually claimed, and from a different molecule. The only controlled adult trial — 19 people, 16 weeks, the norleucine-27 analogue at 10 mcg/kg nightly — found increased lean body mass in MEN ONLY, no change in body fat in either sex, and no change in bone mineral density [7]. There is no trial showing fat loss.

Performance and Recovery

No trial has measured strength, endurance or training recovery with this compound. What the adult analogue trial did measure was self-reported general well-being and libido, both improved in men only, and sleep quality, which did not change [7]. Treat performance claims as untested.

Dosing

How much do I take?

10 mcg/kg/day – 30 mcg/kg/day

Full GHRH (1-29) dosing protocol

Covers all 2 documented dose levels · timing · dose-adjustment guidance.

GHRH (1-29)Once daily at bedtime

How much peptide is in your bottle?

Look at the label on the vial. It’s the number next to mg — like "5 mg".

Type a number to continue.

Suitability

Is this right for me?

Best for children with growth hormone deficiency who need to catch up in height & adults seeking to optimize natural growth hormone levels

Best for

Helping Kids Catch Up in Height

Children with growth hormone deficiency grow slowly because the signal to release growth hormone is weak. GHRH(1-29) supplies that signal. In the 110-child trial behind the approval, 30 mcg/kg at bedtime nearly doubled height velocity in the first 6 months, and bone age advanced in step with height rather than racing ahead of it [5]. It is also fair to say that growth hormone itself worked better, which is part of why this product left the market [1].

Testing for Growth Problems

A single intravenous dose of 1 mcg/kg is a rapid and relatively specific test of whether the pituitary can release growth hormone, and it produces fewer false positives in children without deficiency than other provocative tests. A normal response does not rule deficiency out, though — a hypothalamic cause can pass this test, so it is used alongside conventional testing rather than instead of it [1].

Adults — what is actually known

GHRH works upstream: it asks the pituitary to release its own growth hormone rather than replacing the hormone, so the body's feedback loops stay in the circuit. That is a real mechanical difference from injecting growth hormone. What it has not been shown to do is change how adults look or perform. The only controlled adult trial ran 16 weeks in 19 people aged 55-71, used a modified version of the molecule, and found lean mass and well-being improved in men but not women, with no change in body fat [7][8]. No trial has tested sermorelin itself in healthy adults.

Consider alternatives if

Longer-lasting GH stimulationCJC-1295, CJC-1295 DAC

Different mechanism of GH releaseGHRP-6, Ipamorelin

Synthetic GH replacement therapySomatropin (synthetic human growth hormone)

Do not use if

You have a known sensitivity to sermorelin or any excipient — the label's contraindicationYou are pregnant or breastfeeding — there is no human dataYou have an intracranial lesion — such patients were excluded from the studies the approval rests onYou are looking for height gain after the growth plates have fused — the label stops treatment at that point, and no dose reopens them

Use with caution if

You have untreated hypothyroidism — the label requires thyroid testing before and during treatment, and hypothyroidism developed in 6.5% of patients on therapyYou have diabetes or impaired glucose tolerance — the paediatric trial found no change in fasting glucose [5], but growth hormone itself raises blood sugar and no adult metabolic safety data exists beyond 16 weeksYou are taking corticosteroids — they blunt the growth hormone responseYou are a woman expecting the adult results reported for men — lean mass, insulin sensitivity, well-being and libido improved in men only [7]

Not sure?

Compare GHRH (1-29) with similar peptides to find the best fit for your goals.

GHRH (1-29) vs Ipamorelin GHRH (1-29) vs CJC-1295 (No DAC)GHRH (1-29) vs CJC-1295 with DAC

Administration

How do I use it?

Subcutaneous injection · Intravenous (diagnostic test only)

Route

Subcutaneous injection into the fatty tissue layer just under the skin

Best sites

Lower abdomen (avoid area directly around the navel)Outer thigh (front or side)Upper arm (back of upper arm is ideal)Buttocks (upper outer quadrant)

GHRH (1-29) dosing protocol GHRH (1-29) injection guide

Covers reconstitution · step-by-step technique · storage · a sample daily schedule.

Safety

Is it safe?

2 common side effects · 2 serious

The largest safety dataset is the 110-child pivotal trial, where 30 mcg/kg/day for up to a year produced no adverse changes in general biochemical or hormonal analyses, no change in fasting glucose, and no excessive IGF-I generation [5].

Across the paediatric programme the most commonly reported adverse events were transient facial flushing and pain at the injection site [1].

The Geref prescribing information puts numbers on that: an injection reaction — pain, swelling or redness — in about 1 patient in 6, with 3 of 350 exposed patients discontinuing because of it; hypothyroidism in 6.5% during therapy, which is why the label requires thyroid testing before and during treatment; and anti-GRF antibodies in a large proportion of patients at least once during treatment, of unclear significance and with no apparent effect on growth.

In the 19-adult trial of the norleucine-27 analogue the only adverse effect was transient hyperlipidaemia, which resolved by the end of the study [7], and the companion immune paper reported no adverse effects [8].

Sermorelin was approved in 1997 for growth failure in children with growth hormone deficiency, on the strength of open-label paediatric trials rather than placebo-controlled ones — the 110-child pivotal study had no control arm [5], and neither did the nine-child radiation study [6].

The manufacturer discontinued it in 2008 and no FDA-approved sermorelin product is marketed in the United States; what is sold is compounded. Adult evidence is one 19-person trial, 16 weeks long, of a different molecule [7][8].

There is no long-term adult safety data, no trial in healthy young adults, no cancer-risk data, and no data in pregnancy. Patients with intracranial lesions were excluded from the paediatric studies.

Common side effects · experienced by some users

Transient facial flushing
One of the two most commonly reported adverse events across the paediatric programme, along with injection-site pain [1]. It follows the injection and passes.
Management: No treatment is specified. It is transient and reported as mild.
Injection site reaction
Pain, swelling or redness at the injection site, in about 1 patient in 6 on the Geref prescribing information. Of 350 patients exposed in clinical trials, 3 stopped treatment because of it — so it is common but rarely severe enough to end therapy.
Management: Rotate injection sites, which the label asks for explicitly.

Less common

HypothyroidismAnti-GRF antibodiesTransient raised blood lipids

These typically resolve with continued use or dose adjustment.

Stop and seek help if

Any sign of hypersensitivity beyond the transient flush — hives, swelling of the face or throat, difficulty breathing
An injection-site reaction that is severe or persistent; this ended treatment for 3 of 350 exposed patients
Thyroid function turning abnormal — the label requires monitoring for this
The growth plates have fused, if height was the goal — the label discontinues treatment at that point
Pregnancy confirmed or planned

There is no FDA-approved sermorelin product on the US market — Geref was discontinued in 2008, and what is sold today is compounded. The approved use was growth failure in children with growth hormone deficiency. Adult use is investigational and rests on a single 19-person trial of a modified molecule. This needs a prescriber, including for the thyroid monitoring the original label required.

With other peptides

Safe:GHRP-6 (growth hormone releasing peptide-6) — Synergistic combination. GHRP-6 works through a different mechanism and amplifies GHRH (1-29) effects for stronger growth hormone release.
Safe:CJC-1295 — Compatible and complementary. CJC-1295 extends GHRH signaling duration, creating sustained GH elevation when combined.
Safe:Ipamorelin — Safe combination with different mechanism. Works alongside GHRH for comprehensive growth hormone support.
Caution:Somatostatin — Direct antagonist. Somatostatin inhibits growth hormone release, directly opposing GHRH (1-29) effects.

With medications

Caution:Corticosteroids (prednisone, dexamethasone) — High-dose corticosteroids suppress growth hormone secretion and reduce GHRH (1-29) effectiveness.
Safe:Thyroid medications (levothyroxine) — Safe and often beneficial. Proper thyroid function supports optimal growth hormone response.
Safe:Diabetes medications — Monitor carefully. Growth hormone raises blood sugar, so diabetes medication doses may need adjustment.
Safe:Blood pressure medications — Generally safe. Growth hormone can mildly affect blood pressure, so monitor readings periodically.

With supplements

Safe:Zinc supplementation — Beneficial. Zinc supports immune function and may enhance growth hormone production.
Safe:Arginine supplements — Complementary. Arginine is a precursor for growth hormone and works well alongside GHRH (1-29).
Safe:Glutamine — Safe and supportive. Glutamine helps preserve muscle and supports immune function during GH optimization.

Effectiveness

How do I know it's working?

Human trials in children; one 19-person adult trial of a modified analogue · first signs weeks 1-2

Evidence level

Human trials in children; one 19-person adult trial of a modified analogue

Regulatory status

Approved 1997 as Geref for growth failure in children with growth hormone deficiency; discontinued by the manufacturer in July 2008 and no longer marketed in the US

FDA determined in 2013 it was not withdrawn for safety or effectiveness reasons. Sermorelin sold today is compounded, not an FDA-approved product.

Onset of effects

Height velocity measurable at 6 months in children; nothing established in adults

How it works

Your pituitary gland is like a growth hormone factory.

GHRH (1-29) acts like a messenger that tells this factory 'start making more growth hormone right now.' It works with your body's natural systems instead of replacing them, which is why it feels more like optimization than artificial supplementation.

The peptide gets to work in minutes and your growth hormone levels spike, giving your body the signal it needs to build muscle, burn fat, and support growth.

The deeper mechanism

GHRH (1-29) is a 29-amino acid peptide that binds to GHRH receptors located on somatotroph cells in the anterior pituitary gland.

This receptor activation stimulates G-protein coupled signaling cascades that increase intracellular cyclic adenosine monophosphate (cAMP) and calcium concentrations, leading to depolarization and exocytosis of growth hormone-containing secretory granules.

The peptide works synergistically with the natural pulsatile pattern of growth hormone secretion driven by somatostatin withdrawal.

Due to its short half-life of 10-20 minutes, GHRH (1-29) mimics the body's endogenous GH-releasing hormone secretion pattern more closely than longer-acting synthetic analogs.

The peptide demonstrates high specificity for GHRH receptors with minimal off-target effects, explaining its favorable safety profile. When administered at bedtime, it aligns with the circadian GH secretion pattern, utilizing sleep-associated GH pulses for amplified response.

Continuous stimulation with GHRH (1-29) demonstrates that GH pulses are generated by the intermittent withdrawal of somatostatin acting against a permissive GHRH background signal.

What to expect

Weeks 1-2
What you might notice
- Improved sleep quality, especially deeper REM sleep
- Slight increase in energy in the morning
- Possible mild injection site reactions (normal and expected)
What's normal
- Facial flushing after injection (harmless and temporary)
- Minor bruising at injection sites with initial injections
- No dramatic changes yet (GH effects take time to compound)
What's next
- Growth hormone pulsatility is being re-established through daily GHRH stimulation. Continue consistent bedtime dosing to align with natural GH secretion patterns.
- If side effects persist beyond week 2, contact your healthcare provider.
Weeks 3-6
What you might notice
- Better muscle definition and firmness starting to appear
- Increased strength during workouts
- Improved body composition despite unchanged diet
- More consistent energy throughout the day
What's normal
- Gradual changes rather than dramatic overnight transformation
- Continued mild facial flushing (usually lessening over time)
- Injection technique improving and side effects minimizing
What's next
- You're entering the sweet spot for effectiveness. Results compound from here.
- Maintain consistent dosing and timing for best outcomes.
Weeks 7-12
What you might notice
- Noticeable improvements in height velocity if you're a growing child
- Significant body composition changes with improved muscle tone
- Better workout recovery and endurance
- Measurable strength gains
- Improved skin elasticity and appearance
What's normal
- Most significant changes appear in this window
- Facial flushing episodes usually rare by this point
- Consistent, cumulative improvements rather than plateaus
What's next
- Congratulations on completing 12 weeks. Medical evaluation can determine if continuation is beneficial.
- Many protocols continue 8-12 week cycles for sustained benefits.

Signs it's working

Physical Changes

Increased height velocity in children (measurable growth acceleration)
Visible muscle tone and definition improvements
Reduced body fat, especially in midsection
Improved skin texture and elasticity
Better hair and nail quality

Performance and Vitality

Increased strength during exercise without added training
Faster recovery between workouts
Sustained energy throughout the day
Improved sleep quality and duration
Better mental clarity and focus
Improved mood and overall sense of well-being

Not seeing results? Common reasons

Expecting adult results that were never demonstrated. The controlled adult trial found no change in body fat and no change in bone density, and the lean-mass gain was in men only [7]
Expecting sermorelin to match the analogue. The adult data everyone quotes used [Nle27]GHRH-(1-29)-NH2, not sermorelin [7][8]
IGF-I plateauing. In the adult trial IGF-I rose within 2 weeks and then drifted back toward baseline by 16 weeks even though GH stayed elevated — that was the observed course, not a failure of dosing [7]
Untreated hypothyroidism. The label requires thyroid testing before and during treatment, and 6.5% of patients became hypothyroid on therapy — it blunts the growth response
A dose taken from the wrong population. 30 mcg/kg is the paediatric dose; the 200-300 mcg fixed figure is community practice with no trial behind it, and the two differ by roughly tenfold for an adult
Compounded material of unknown purity — there is no approved product to compare it against

Key research

1999[1]

“Sermorelin: A review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency”Prakash A, Goa KLFinding: Sermorelin is the shortest synthetic fragment of growth hormone-releasing hormone with full activity. A single intravenous 1 mcg/kg dose is a rapid and relatively specific test for growth hormone deficiency, producing fewer false positives in children without deficiency than other provocative tests — though a normal response cannot rule out a hypothalamic cause, so it is used alongside conventional testing rather than instead of it. For treatment, the review calls the data limited: once-daily subcutaneous 30 mcg/kg at bedtime raised height velocity over 12 months in some prepubertal children with idiopathic deficiency, with a few children followed to 36 months, and the effect on final adult height was never determined. Height-velocity gains were SMALLER than those in children given somatropin at the same 30 mcg/kg per day. Across that programme — 350 patients exposed to sermorelin in clinical trials — transient facial flushing and injection-site pain were the most commonly reported adverse events.View study

1993[2]

“Pharmacokinetics of GHRH(1-29)-NH2 and stimulation of growth hormone secretion in healthy subjects”Wilton P, et alFinding: In a study of 30 healthy men, even tiny intravenous doses of just 0.25 micrograms per kilogram of body weight produced significant growth hormone release. The maximum growth hormone response occurred at doses of 1-2 micrograms per kilogram, with peak growth hormone levels reaching approximately 90 milli-international units per liter. Growth hormone levels remained elevated for about 3 hours even though the peptide itself was rapidly eliminated from the body. Intranasal delivery had poor bioavailability of only 3-5%, but higher intranasal doses of 50 micrograms per kilogram were as effective as just 1 microgram per kilogram given intravenously. Importantly, repeated intranasal dosing did not suppress the body's natural nighttime growth hormone secretion.View study

2000[3]

“The GH response to low-dose bolus GHRH(1-29)NH2 is attenuated in patients with longstanding post-irradiation GH insufficiency”Achermann JC, et alFinding: Testing with low-dose GHRH(1-29) revealed that patients with growth hormone deficiency caused by radiation therapy showed a reduced growth hormone response compared to healthy individuals. This demonstrated that GHRH(1-29) is a useful diagnostic tool for identifying and characterizing different types of growth hormone deficiency.View study

1999[4]

“The relative roles of continuous GHRH(1-29)NH2 and intermittent somatostatin in GH pulse generation”Achermann JC, et alFinding: Studies using continuous GHRH(1-29) infusions revealed how growth hormone pulses are actually generated in the body. The research showed that growth hormone pulses are created by the intermittent withdrawal of somatostatin (an inhibitory hormone), while GHRH(1-29) provides a permissive background signal that allows growth hormone secretion to occur. This mechanism explains why GHRH(1-29) is so effective at stimulating natural growth hormone release.View study

1996[5]

“Once daily subcutaneous growth hormone-releasing hormone therapy accelerates growth in growth hormone-deficient children during the first year of therapy (Geref International Study Group)”Thorner M, Rochiccioli P, Colle M, Lanes R, Grunt J, Galazka A, Landy H, Eengrand P, Shah SFinding: The trial the approved dose comes from. 110 previously untreated prepubertal growth hormone-deficient children received 30 mcg/kg per day of GHRH(1-29) subcutaneously at bedtime for up to a year in a multicentre open-label study; 86 were eligible for the efficacy analysis. Mean height velocity rose from 4.1 ± 0.9 cm/year at baseline to 8.0 ± 1.5 cm/year at 6 months and 7.2 ± 1.3 cm/year at 12 months, and 74% of the children were judged good responders at 6 months. Bone age advanced in step with height age (ratio 1.04 ± 0.58, p=0.63), fasting glucose did not change, and there was no excessive IGF-I generation. Open-label: there was no placebo arm.View study

1997[6]

“Treatment of radiation-induced growth hormone deficiency with growth hormone-releasing hormone”Ogilvy-Stuart AL, Stirling HF, Kelnar CJ, Savage MO, Dunger DB, Buckler JM, Shalet SMFinding: Nine prepubertal children with growth hormone deficiency caused by cranial or craniospinal irradiation received GHRH(1-29)-NH2 15 mcg/kg TWICE daily by subcutaneous injection for a year — a divided dose, 30 mcg/kg across the day. Height velocity rose from 3.3 cm/year before treatment to 6.0 cm/year (p=0.004). In the following year on growth hormone itself the same children grew 7.5 cm/year, so GHRH worked but worked less well than GH. In that cohort (n=9), with no control arm and no placebo, no adverse events attributable to GHRH and no adverse changes in clinical chemistry, haematology, lipids or thyroid function were recorded over the treatment year — a cohort far too small to detect anything uncommon.View study

1997[7]

“Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women”Khorram O, Laughlin GA, Yen SSFinding: The adult trial — and it tested a different molecule. Ten women and nine men aged 55 to 71 self-injected saline nightly for 4 weeks, then [Nle27]GHRH-(1-29)-NH2 (a norleucine-27 analogue, not sermorelin) at 10 mcg/kg nightly for 16 weeks, single-blind and placebo-controlled. Nocturnal GH rose in both sexes (women p<0.01, men p<0.05) and IGF-I rose within 2 weeks (p<0.05) but drifted back toward baseline by 16 weeks. Skin thickness increased in both sexes (p<0.05). Lean body mass increased in MEN ONLY (p<0.05), with no other change in body composition and no change in bone mineral density in either sex — body fat did not fall. Insulin sensitivity, general well-being (p<0.05) and libido (p<0.01) improved in men only. Sleep quality was unaffected. The only adverse effect was transient hyperlipidaemia, resolved by the end of the study. Nineteen people.View study

1997[8]

“Effects of [norleucine27]growth hormone-releasing hormone (GHRH) (1-29)-NH2 administration on the immune system of aging men and women”Khorram O, Yeung M, Vu L, Yen SSFinding: The same 19 people and the same norleucine-27 analogue at 10 mcg/kg nightly for 16 weeks. Twelve-hour integrated GH rose 107% in men and 70% in women, and IGF-I rose 28%. B cells rose 30% by 16 weeks with a 50% increase in responsiveness to B-cell mitogens, lymphocytes expressing the IL-2 receptor rose 70%, and T-cell responsiveness to phytohaemagglutinin rose 50%. Total T cells, T-cell subsets and natural killer cells did not change. The authors report no adverse effects. Again: 19 people, an analogue rather than sermorelin, and immune cell counts rather than any clinical outcome such as infection rate.View study

Questions

Frequently asked

How fast does GHRH (1-29) work?

Growth hormone levels rise within minutes of injection, but you won't see dramatic physical changes immediately. Most people notice improvements in sleep quality and energy within 1-2 weeks. Real physical changes like muscle definition and body composition improvements typically appear between weeks 3-6. It's a steady, compound effect rather than an overnight transformation.

Is GHRH (1-29) the same as synthetic growth hormone?

No, they're different approaches. GHRH (1-29) tells your pituitary gland to make its own growth hormone. Synthetic growth hormone (somatropin) is artificial GH you inject directly. GHRH (1-29) is more like flipping the 'on' switch for your body's own hormone factory, while synthetic GH is like pouring fuel directly into the tank.

Why inject at bedtime specifically?

Your body naturally releases growth hormone in waves during sleep, especially during deep sleep. Injecting GHRH (1-29) at bedtime times with your body's natural rhythms, amplifying your already-existing nighttime growth hormone surge. This approach is smarter and more effective than random injections throughout the day.

Will my body stop making growth hormone if I use GHRH (1-29)?

No. GHRH (1-29) stimulates your pituitary to produce more growth hormone naturally. It's not replacing your system; it's enhancing it. When you stop using it, your body's growth hormone production returns to normal. You're not creating dependency.

Can I use GHRH (1-29) long-term?

The cycling protocols quoted for this compound — 8-12 weeks on, then a break — come from community practice, not from any trial or label. The approved use ran the opposite way: continuous nightly dosing until the growth plates fuse, and the paediatric trials dosed daily for a full year without breaks [5][6]. The longest adult exposure ever published is 16 weeks, in 19 people, using a modified version of the molecule [7]. So there is no evidence for or against cycling, and no long-term adult safety data at all.

What should I expect if I combine GHRH (1-29) with other peptides?

GHRH (1-29) works great with peptides like GHRP-6 and CJC-1295 because they use different mechanisms that complement each other. Together, they create stronger, more sustained growth hormone elevation. Never combine with somatostatin, which directly opposes GHRH's action. Always space injections a few minutes apart.

History & related research

History · since 1982

The brain's forgotten hormone that sparked a Nobel Prize feud and changed how we treat growth disorders.

Sermorelin is a 29-amino acid peptide that tells your pituitary gland to make its own growth hormone. Unlike synthetic injections, it works with your body's natural system.

Read the full history of GHRH (1-29)

Ready for the protocol?

Every dosing tier, administration route, timing note, and dose-adjustment rule for GHRH (1-29), on one page.

GHRH (1-29) dosing protocol

Peptide Database