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
Subcutaneous
Route
4 recommended
Sites
Once daily at bedtime
Frequency
Preparation
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
Pro tip
Prepare all supplies on a clean surface before you begin. Having everything ready makes the process smoother and more sterile.
Mixing
Wash your hands thoroughly with soap and water. Gather all supplies on a clean, flat surface.
Remove the plastic cap from the peptide vial and wipe the rubber stopper with an alcohol swab. Let it air dry.
Draw the appropriate amount of bacteriostatic water into a sterile syringe.
Insert the needle into the vial at an angle, aiming at the inside wall of the vial. Slowly push the plunger to let the water trickle down the glass wall -- do NOT squirt directly onto the powder.
Once all water is added, gently swirl the vial in a slow circular motion. Never shake the vial, as this can damage the peptide bonds.
Continue swirling until the powder is completely dissolved and the solution is clear. If particles remain, let the vial sit for a few minutes and swirl again.
Label the vial with the date of reconstitution, the peptide name, and the concentration (e.g. 250mcg per 0.1mL).
Example calculation
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.
Dose calculation
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.
Pro tip
Always add the bacteriostatic water slowly, letting it run down the side of the vial. Never shake the vial -- swirl gently to avoid damaging the peptide.
Location
Site 01
Abdomen
Pinch the skin 2 inches from navel. Avoid the area directly around the belly button. Rotate between left and right sides.
Site 02
Outer Thigh
Middle third of the outer thigh. Keep at least 4 inches above the knee and below the hip. Alternate legs each injection.
Site 03
Upper Arm
Back or outer area of the upper arm. This site may require assistance from another person for proper technique.
Site 04
Gluteal
Upper outer quadrant of the buttock. This site is best for intramuscular injections and larger volumes.
Rotate between 4 sites to prevent tissue buildup and ensure consistent absorption.
Pro tip
Rotate your injection sites with each dose to prevent lipohypertrophy (buildup of fatty tissue). Keep a simple log of where you last injected.
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.
Pro tip
This peptide uses subcutaneous injection into the fatty tissue layer just under the skin. Inject at a 45-90 degree angle into pinched skin. Aspirate before injecting to ensure you haven't hit a blood vessel.
Timing
Optimal timing
Best time
At bedtime. Every paediatric trial and the approved label dosed at night, to land on the body's own overnight growth hormone pulse [1][5]. The adult analogue trial injected at 2100 h [7].
With food?
No trial controlled for food and the label sets no food restriction. Subcutaneous absorption does not depend on stomach contents.
Stacking notes
No human trial has combined sermorelin with another peptide. What has been studied is the pharmacology: GHRH(1-29) and a growth hormone secretagogue given together produce a much larger GH release than either alone, and that synergy holds even against a high somatostatin 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.
Sample daily schedule
At bedtime
30 mcg/kg injection
Site: Rotate subcutaneous injection sites — the label asks for this explicitly
Bedtime dosing is what the label and every paediatric trial used, and it is the only timing with evidence behind it [1][5]. The 30-minute-before-bed, empty-stomach instruction previously published here had no source: no trial controlled for food, and a subcutaneous injection is not affected by stomach contents. The 100-300 mcg figure that used to sit in this field contradicted the weight-based dose on the same page and has been removed.
Dosing tiers
Dose
30 mcg/kg/day
Frequency
Once daily at bedtime
Duration
Continuous — trials ran 12 months; the label treats until the growth plates fuse
The approved Geref dose and the only dose of this molecule tested once daily: 30 mcg/kg (0.03 mg/kg) subcutaneously 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].
Dose
10 mcg/kg/day
Frequency
Once nightly
Duration
16 weeks in the only controlled adult trial
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, not sermorelin — at 10 mcg/kg nightly for 16 weeks in 19 people aged 55 to 71 [7][8]. 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, 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.
Preservation
Before mixing
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
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.
Shelf life after mixing
24 hours when stored properly in refrigerator
Signs of degradation
Discard the vial immediately if you notice any of these:
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
Important
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.
Clean technique checklist
Wash hands thoroughly with soap and water before handling supplies
Swab vial tops and injection site with alcohol and let dry
Never touch the needle tip or allow it to contact non-sterile surfaces
Use a new syringe and needle for each injection
Dispose of used sharps in a proper sharps container
Store reconstituted peptides according to the storage instructions above
Published research
Prakash A, Goa KL · 1999
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.
Wilton P, et al · 1993
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.
Achermann JC, et al · 2000
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.
Achermann JC, et al · 1999
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.
Thorner M, Rochiccioli P, Colle M, Lanes R, Grunt J, Galazka A, Landy H, Eengrand P, Shah S · 1996
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.
Ogilvy-Stuart AL, Stirling HF, Kelnar CJ, Savage MO, Dunger DB, Buckler JM, Shalet SM · 1997
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.
Khorram O, Laughlin GA, Yen SS · 1997
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.
Khorram O, Yeung M, Vu L, Yen SS · 1997
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.
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