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Growth hormone

GHRH (1-29), explained simply

The shortest fully active piece of growth hormone-releasing hormone. Approved in 1997 as Geref for children with growth hormone deficiency, then discontinued in 2008.

Human trials in children; one 19-person adult trial of a modified analogueInjection under the skin (like insulin shots)8 cited sourcesResearch compound — not FDA approved

Start here

What is GHRH (1-29)?

GHRH(1-29) is the active piece of growth hormone-releasing hormone — the body's main signal telling the pituitary (the master hormone gland at the base of the brain) gland to make growth hormone — and the shortest fragment that keeps the full hormone's activity. It was FDA-approved in 1997 as Geref for growth failure in children with growth hormone deficiency, but the manufacturer discontinued it in 2008 and it is no longer sold in the US 157. The FDA later determined it was not withdrawn for safety or effectiveness reasons; the sermorelin sold today is compounded, not an FDA-approved product.

How it works in your body

Your pituitary (the master hormone gland at the base of the brain) 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.

Why researchers care

GHRH(1-29) has been used in two ways: as a treatment that prompts the body to release its own growth hormone in people whose levels are too low, and as a quick test of whether the pituitary (the master hormone gland at the base of the brain) gland can respond when asked to make growth hormone.

The deeper mechanism, for the curious

GHRH (1-29) is a chain of 29 amino acids that attaches to GHRH receptors on somatotroph cells (growth-hormone-making cells) in the front part of the pituitary (the master hormone gland at the base of the brain) gland. This triggers signal chains inside the cell (through G-proteins) that raise levels of cyclic adenosine monophosphate (cAMP) and calcium. The cell's electrical charge then shifts (depolarization) and it releases packets of stored growth hormone (exocytosis). It works together with the body's natural pulsing pattern of growth hormone release, which is driven by somatostatin (the hormone that switches growth hormone release off) withdrawal (the pulling back of a hormone that normally holds growth hormone down). Because its half-life (how long it stays active in your body) is short, 10-20 minutes, GHRH (1-29) copies the body's own GH-releasing hormone pattern more closely than longer-acting lab-made versions. It binds GHRH receptors very selectively with minimal off-target effects, which explains its good safety profile. Given at bedtime, it lines up with the body's daily growth hormone rhythm and uses the pulses that come with sleep for a bigger response. Continuous GHRH (1-29) stimulation shows that GH pulses come from the on-and-off withdrawal of somatostatin acting against a steady GHRH background signal that allows release.

Evidence check

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

We couldn't classify the research behind this one — read the full profile before forming an opinion.

Every numbered marker on this page links to one of the 8 sources at the bottom.

95/100

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. Growth hormone itself produced larger gains at the same dose per kilogram.

85/100

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. There is no trial showing fat loss.

80/100

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. Treat performance claims as untested.

What the research points to

  • Stimulates natural growth hormone release from your pituitary (the master hormone gland at the base of the brain) gland
  • Helps children with growth hormone deficiency reach normal heights
  • Promotes muscle development and lean body mass
  • Supports bone density and skeletal strength
  • Quick testing tool for diagnosing growth hormone problems
  • Minimal side effects compared to synthetic growth hormone

The most-asked question

How much GHRH (1-29) do I take?

The research-reported range is 30 mcg/kg/day, once daily at bedtime. Studies used different doses for different situations — find yours:

  1. Growth hormone deficiency in children (the approved use), Growth hormone stimulation testing, at a much lower intravenous dose

    30 mcg/kg/day

    • How often
      Once daily at bedtime
    • For how long
      Ongoing — trials ran 12 months; the label says to treat until the growth plates (the areas at the ends of bones where growth happens) close
    • How
      Injection under the skin

    The approved Geref dose and the only dose of this molecule tested once daily: 30 mcg/kg (0.03 mg/kg) subcutaneously (under the skin) at bedtime in prepubertal children with growth hormone deficiency. In the 110-child pivotal trial it raised height velocity from 4.1 to 8.0 cm/year at 6 months 5. The same 30 mcg/kg total has also been given as 15 mcg/kg TWICE daily in children with radiation-induced deficiency 6. Two things this dose is not: it is not an adult dose — no trial has given sermorelin at 30 mcg/kg to adults, and for a 75 kg adult it would be 2,250 mcg — and it is not equivalent to growth hormone, which produced larger height gains at the same microgram-per-kilogram dose 1.

  2. Adult GH axis stimulation (investigational, and with a modified analogue)

    10 mcg/kg/day

    • How often
      Once nightly
    • For how long
      16 weeks in the only controlled adult trial
    • How
      Injection under the skin

    Read the molecule before you read the number. The only controlled trial in older adults used [Nle27]GHRH-(1-29)-NH2 — a norleucine-27 analogue (a modified version of a natural molecule), not sermorelin — at 10 mcg/kg nightly for 16 weeks in 19 people aged 55 to 71 78. That is roughly 750 mcg for a 75 kg adult. GH and IGF-I rose, but IGF-I drifted back toward baseline by week 16; lean mass, insulin sensitivity (how well your body responds to insulin), well-being and libido improved in men only; body fat and bone density did not change in either sex; sleep was unaffected 7. The fixed 200-300 mcg nightly figure that circulates for adults is community practice — it appears in no trial and on no label, and it is 3 to 4 times below this studied dose. It is listed here because people use it, not because it has evidence behind it.

Adjusting your dose

You're at the right dose if…

Consider going up if…

Go down if…

  • Injection-site reactions are severe or persistent — they caused 3 of 350 exposed patients to stop treatment on the prescribing information
  • Facial flushing is severe rather than transient
  • Your prescriber's monitoring calls for it

The ceiling: 30 mcg/kg once daily is the approved dose and the highest daily amount any trial of this molecule gave 5. The previous entry here, 300 mcg daily, was below the approved dose for anyone over 10 kg and was not a maximum of anything.

Reconstitution, in plain words

How do I mix GHRH (1-29)?

Peptides usually arrive as a freeze-dried powder in a small vial. “Reconstitution” just means adding sterile water back in so you can measure a dose. Here's how it works for GHRH (1-29):

What you need

  • Sterile bacteriostatic water (0.9% sodium chloride or supplied diluent)
  • Sterile needle and syringe (25-gauge 1mL syringe recommended)
  • Alcohol prep pads for sanitizing vial tops
  • Puncture-resistant sharps disposal container

A worked example

If you weigh 70 kg and use the 30 mcg/kg dose: 70 kg × 30 mcg/kg = 2,100 mcg total daily dose. If your vial contains 5 mg (5,000 mcg) in 5mL of sterile water after reconstitution, you'd inject 2.1 mL.

Working out your dose

Multiply your body weight in kg by 30 mcg/kg for starting dose. For standard therapy, use 100-300 mcg based on medical guidance. Concentration = total mcg in vial ÷ mL of diluent added. Your dose volume = desired mcg ÷ concentration.

Or let the calculator do it

Three quick questions — your vial, your water, your dose — and it tells you the exact syringe mark. “Find dose amount” is preloaded with GHRH (1-29)'s recorded schedule.

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 the unit — like "5 mg". Labeled in IU? Switch the unit to IU.

Type a number to continue.
0

Injection sites & technique

Where do I inject GHRH (1-29)?

The best spots

  • 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)

How to do it, step by step

  • Clean the injection site with an alcohol prep pad using circular motions for 30 seconds. Let dry completely (don't fan dry).
  • Hold the skin at the site with one hand and gently pinch to create a fold of fatty tissue.
  • Insert the needle at a 45-90 degree angle quickly and smoothly into the fatty layer until the needle is mostly in, but not fully.
  • Push the plunger slowly and steadily to inject the medication over 3-5 seconds. Keep steady pressure.
  • Withdraw the needle and gently massage the injection site for 10 seconds. This helps distribute the medication and reduce bruising.

Subcutaneous (under the skin) injection into the fatty tissue layer just under the skin

Timing

When do I take GHRH (1-29)?

Best time of day

At bedtime. Every paediatric trial and the approved label dosed at night, to land on the body's own overnight growth hormone pulse 15. The adult analogue (a modified version of a natural molecule) trial injected at 2100 h 7.

With or without food?

No trial controlled for food and the label sets no food restriction. Subcutaneous (under the skin) absorption does not depend on stomach contents.

Taking it with other peptides

No human trial has combined sermorelin with another peptide. What has been studied is the pharmacology: GHRH(1-29) and a growth hormone secretagogue (a compound that prompts your body to release growth hormone) given together produce a much larger GH release than either alone, and that synergy holds even against a high somatostatin (the hormone that switches growth hormone release off) infusion 4. That is a mechanism finding in controlled laboratory conditions, not a protocol, and nobody has tested whether the combination is safe or useful over time.

The honest list

What side effects could GHRH (1-29) cause?

Common — usually mild

These show up most often. They usually fade as your body adjusts.

  • Short-lived 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.

    What to do 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.

    What to do Rotate injection sites, which the label asks for explicitly.

Less common

Worth knowing about, but most people never see these.

  • Underactive thyroid (hypothyroidism)

    The Geref prescribing information reports hypothyroidism in 6.5% of patients during therapy. This is the reason the label requires thyroid hormone testing before starting and throughout treatment — untreated hypothyroidism also blunts the growth response.

    What to do Thyroid function testing before treatment and during it, per the label. This needs a prescriber, not self-monitoring.

  • Antibodies against growth hormone-releasing factor (the immune system reacting to the drug)

    The prescribing information states that a large proportion of patients develop antibodies to GRF at least once during treatment. Their significance is not established and their presence did not appear to affect growth.

    What to do No action specified on the label.

  • Short-lived rise in blood fats (lipids)

    In the 19-person adult trial of the norleucine-27 analogue (a modified version of a natural molecule) this was the only adverse effect recorded, and it resolved by the end of the 16-week study 7.

    What to do It cleared up without any treatment in that trial. A blood fat (cholesterol) test is a reasonable check.

Serious — stop and get medical help

Rare, but if any of these happen, stop and contact a medical professional.

  • Allergic (hypersensitivity) reaction

    Known sensitivity to sermorelin or any excipient is the label's contraindication. Hives, swelling of the face or throat, or difficulty breathing are not the transient flush.

    What to do Stop and seek emergency care.

Week by week

What should I expect from GHRH (1-29), and when?

  1. Weeks 1-2

    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.

  2. Weeks 3-6

    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.

  3. Weeks 7-12

    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.

How to tell it's actually 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 anything? The usual reasons

Is it right for you?

Who should avoid GHRH (1-29)?

Do not use it if…

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

Be extra careful if…

When to stop

  • 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.

What it mixes badly (and well) with

Medications

  • Avoid
    Corticosteroids (prednisone, dexamethasone)

    High-dose corticosteroids suppress growth hormone secretion and reduce GHRH (1-29) effectiveness.

  • OK together
    Thyroid medications (levothyroxine)

    Safe and often beneficial. Proper thyroid function supports optimal growth hormone response.

  • Check first
    Diabetes medications

    Monitor carefully. Growth hormone raises blood sugar, so diabetes medication doses may need adjustment.

  • Check first
    Blood pressure medications

    Generally safe. Growth hormone can mildly affect blood pressure, so monitor readings periodically.

Other peptides

  • OK together
    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.

  • OK together
    CJC-1295

    Compatible and complementary. CJC-1295 extends GHRH signaling duration, creating sustained GH elevation when combined.

  • OK together
    Ipamorelin

    Safe combination with different mechanism. Works alongside GHRH for comprehensive growth hormone support.

  • Avoid
    Somatostatin

    Direct antagonist (a compound that blocks a receptor). Somatostatin (the hormone that switches growth hormone release off) inhibits growth hormone release, directly opposing GHRH (1-29) effects.

Supplements

  • OK together
    Zinc supplementation

    Beneficial. Zinc supports immune function and may enhance growth hormone production.

  • OK together
    Arginine supplements

    Complementary. Arginine is a precursor for growth hormone and works well alongside GHRH (1-29).

  • OK together
    Glutamine

    Safe and supportive. Glutamine helps preserve muscle and supports immune function during GH optimization.

Who it tends to suit

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 (the master hormone gland at the base of the brain) 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 (the brain region that runs your hormone system) 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 (the master hormone gland at the base of the brain) 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 78. No trial has tested sermorelin itself in healthy adults.

The safety picture overall

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 (a modified version of a natural molecule) 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 78. 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.

Keeping it good

How do I store GHRH (1-29)?

Before mixing (powder)

Keep your GHRH (1-29) vial in the refrigerator at 2-8°C (36-46°F). Don't freeze it. Keep it in its original box, away from direct light. Check the expiration date before each use.

After mixing (liquid)

Once you mix the powder with sterile water, it becomes even more delicate. Store the reconstituted vial upright in the refrigerator at 2-8°C immediately. Use within 24 hours of mixing for best results.

Signs it has gone bad

  • Cloudy or discolored solution (should be clear)
  • Visible particles floating in the liquid
  • Vial has been at room temperature for more than 1 hour
  • Liquid has been stored longer than 24 hours after mixing

Not our opinion — the published record

What the studies actually found about GHRH (1-29)

1999

Sermorelin: A review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency

Sermorelin is the shortest lab-made piece of growth hormone-releasing hormone (GHRH) with full activity. A single intravenous (into a vein) 1 mcg/kg dose is a quick and fairly specific test for growth hormone deficiency, giving fewer false positives in children without the deficiency than other stimulation tests. A normal response cannot rule out a hypothalamic cause (a problem in the brain's hormone control center), so it is used alongside standard testing, not instead of it. For treatment, the review calls the data limited: once-daily 30 mcg/kg injected under the skin at bedtime raised height velocity (growth speed) over 12 months in some prepubertal children with idiopathic deficiency (deficiency with no known cause), 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 (lab-made growth hormone) at the same 30 mcg/kg per day. Across that program, 350 patients were given sermorelin in clinical trials, and transient (short-lived) facial flushing and injection-site pain were the most commonly reported side effects.

Prakash A, Goa KL

1993

Pharmacokinetics of GHRH(1-29)-NH2 and stimulation of growth hormone secretion in healthy subjects

In a study of 30 healthy men, even tiny intravenous doses (into a vein) 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 stayed high for about 3 hours even though the peptide itself was cleared quickly from the body. Intranasal delivery (through the nose) had poor bioavailability (the share that reaches the blood) 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 release.

Wilton P, et al

1999

The relative roles of continuous GHRH(1-29)NH2 and intermittent somatostatin in GH pulse generation

Studies using continuous GHRH(1-29) infusions showed how growth hormone pulses are actually produced in the body. Growth hormone pulses come from the on-and-off withdrawal of somatostatin (a hormone that holds growth hormone down), while GHRH(1-29) provides a steady background signal that allows growth hormone release. This mechanism explains why GHRH(1-29) is so effective at stimulating natural growth hormone release.

Achermann JC, et al

1996

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)

The trial the approved dose comes from. 110 previously untreated prepubertal (before puberty) children with growth hormone deficiency received 30 mcg/kg per day of GHRH(1-29) under the skin at bedtime for up to a year in a multicentre open-label study (many sites; everyone knew they were getting the drug); 86 were eligible for the efficacy analysis. Mean height velocity (growth speed) 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 (blood sugar) did not change, and there was no excessive IGF-I generation (IGF-I is a growth signal made in response to growth hormone). Open-label: there was no placebo arm.

Thorner M, Rochiccioli P, Colle M, Lanes R, Grunt J, Galazka A, Landy H, Eengrand P, Shah S

1997

Treatment of radiation-induced growth hormone deficiency with growth hormone-releasing hormone

Nine prepubertal children with growth hormone deficiency caused by cranial or craniospinal irradiation (radiation to the head or to the head and spine) received GHRH(1-29)-NH2 15 mcg/kg TWICE daily by injection under the skin for a year, a divided dose, 30 mcg/kg across the day. Height velocity (growth speed) 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 group (n=9), with no control arm and no placebo, no side effects attributable to GHRH and no harmful changes in clinical chemistry, haematology (blood counts), lipids (blood fats) or thyroid function were recorded over the treatment year. The group was far too small to detect anything uncommon.

Ogilvy-Stuart AL, Stirling HF, Kelnar CJ, Savage MO, Dunger DB, Buckler JM, Shalet SM

1997

Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women

The adult trial, and it tested a different molecule. Ten women and nine men aged 55 to 71 injected themselves with saline every night for 4 weeks, then [Nle27]GHRH-(1-29)-NH2 (a norleucine-27 analogue, a modified version, not sermorelin) at 10 mcg/kg every night for 16 weeks, single-blind (participants did not know what they got) and placebo-controlled. Nocturnal GH (night-time growth hormone) 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 (non-fat tissue) increased in MEN ONLY (p<0.05), with no other change in body composition and no change in bone mineral density (bone strength) in either sex; body fat did not fall. Insulin sensitivity, general well-being (p<0.05) and libido (sex drive) (p<0.01) improved in men only. Sleep quality was unaffected. The only side effect was transient hyperlipidaemia (short-lived high blood fats), resolved by the end of the study. Nineteen people.

Khorram O, Laughlin GA, Yen SS

1997

Effects of [norleucine27]growth hormone-releasing hormone (GHRH) (1-29)-NH2 administration on the immune system of aging men and women

The same 19 people and the same norleucine-27 analogue at 10 mcg/kg every night for 16 weeks. Twelve-hour integrated GH (total growth hormone over 12 hours) rose 107% in men and 70% in women, and IGF-I rose 28%. B cells (antibody-making immune cells) rose 30% by 16 weeks with a 50% increase in responsiveness to B-cell mitogens (substances that trigger B cells to multiply), lymphocytes expressing the IL-2 receptor (activated immune cells) rose 70%, and T-cell responsiveness to phytohaemagglutinin (a plant substance used to test T cells) rose 50%. Total T cells, T-cell subsets and natural killer cells did not change. The authors report no side effects. Again: 19 people, an analogue rather than sermorelin, and immune cell counts rather than any clinical outcome such as infection rate.

Khorram O, Yeung M, Vu L, Yen SS

If this isn't the right fit

What people use instead of GHRH (1-29)

Longer-lasting growth hormone (GH) stimulation

  • CJC-1295
  • CJC-1295 DAC

A different way of triggering growth hormone (GH) release

  • GHRP-6
  • Ipamorelin

Lab-made growth hormone (GH) replacement

  • Somatropin (synthetic human growth hormone)

Your questions

GHRH (1-29) FAQ

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 (the master hormone gland at the base of the brain) 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 (the master hormone gland at the base of the brain) 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 56. 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.

8 sources

References

Every numbered marker on this page points to one of these. Same sources, same numbering as the GHRH (1-29) research profile on Peptide Initiative.

  1. Sermorelin: A review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiencyPrakash A, Goa KL · 1999
  2. Pharmacokinetics of GHRH(1-29)-NH2 and stimulation of growth hormone secretion in healthy subjectsWilton P, et al · 1993
  3. The GH response to low-dose bolus GHRH(1-29)NH2 is attenuated in patients with longstanding post-irradiation GH insufficiencyAchermann JC, et al · 2000
  4. The relative roles of continuous GHRH(1-29)NH2 and intermittent somatostatin in GH pulse generationAchermann JC, et al · 1999
  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 S · 1996
  6. Treatment of radiation-induced growth hormone deficiency with growth hormone-releasing hormoneOgilvy-Stuart AL, Stirling HF, Kelnar CJ, Savage MO, Dunger DB, Buckler JM, Shalet SM · 1997
  7. Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and womenKhorram O, Laughlin GA, Yen SS · 1997
  8. Effects of [norleucine27]growth hormone-releasing hormone (GHRH) (1-29)-NH2 administration on the immune system of aging men and womenKhorram O, Yeung M, Vu L, Yen SS · 1997

Want the deep science?

Read the full GHRH (1-29) research profile

Every claim on this page traces back to the research database behind Peptide Initiative — studies, citations, clinical trial data, and the technical detail we deliberately left out here.

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This guide is education, not medical advice. GHRH (1-29) is a research compound that is not FDA-approved for human use. Talk to a clinician before taking anything.