Trust signals
Written by the FormBlends Medical Team. Reviewed against primary pharmacokinetic literature, the original FDA labeling for Geref (sermorelin acetate), and published compounding guidance. No financial relationship with any sermorelin manufacturer. Last updated 2026-05-29.Key Takeaways
- Units are meaningless without knowing your vial's reconstitution ratio. 40 units can equal 200 mcg or 400 mcg depending on how the vial was prepared.
- The most common compounding protocol uses 200 to 300 mcg per night subcutaneously, which equals 20 to 60 units depending on the vial concentration.
- Sermorelin's plasma half-life after subcutaneous injection is approximately 10 to 20 minutes, making timing relative to sleep physiologically rational.
- The only FDA-approved sermorelin product (Geref) was approved for pediatric GH deficiency at 0.03 mg/kg/day. Adult wellness dosing is off-label and evidence quality is low.
- Tesamorelin has far stronger RCT evidence for GH-axis outcomes than sermorelin. Any comparison that omits this fact is incomplete.
How many units of sermorelin per day?
Most compounding protocols prescribe 200 to 300 mcg of sermorelin per day at bedtime. On the most common vial configuration, 1 mg reconstituted in 2 mL bacteriostatic water, that equals 40 to 60 units on a standard U-100 insulin syringe. Units without a known reconstitution ratio are not a meaningful dose.Table of Contents
- What does one unit of sermorelin actually mean?
- How do I calculate my dose in units from the vial?
- What dose range do clinicians actually use?
- Evidence ledger: what does the research actually support?
- How does sermorelin work and what do the numbers say?
- What most sermorelin pages get wrong
- When should the dose be taken and why does timing matter?
- Honest head-to-head: sermorelin vs. alternatives
- Operational and label literacy: reading your vial and COA
- Stability and formulation: what degrades your peptide
- FAQ
- Sources
What does one unit of sermorelin actually mean?
A "unit" on an insulin syringe is a volume measurement, not a weight or potency measurement. One unit on a U-100 syringe equals 0.01 mL of solution. The microgram dose delivered per unit depends entirely on how concentrated your solution is, which is set by how much bacteriostatic water you added to the lyophilized powder.
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Try the BMI Calculator →This is the single most important conceptual point. A prescription for "30 units of sermorelin" has no biological meaning until you know the vial concentration. Two patients injecting 30 units could be receiving completely different doses.
| Vial Contents (mg) | Bacteriostatic Water Added (mL) | Concentration (mcg/mL) | mcg per 1 Unit | Units for 200 mcg | Units for 300 mcg |
|---|---|---|---|---|---|
| 1 mg | 1 mL | 1000 mcg/mL | 10 mcg | 20 units | 30 units |
| 1 mg | 2 mL | 500 mcg/mL | 5 mcg | 40 units | 60 units |
| 3 mg | 3 mL | 1000 mcg/mL | 10 mcg | 20 units | 30 units |
| 6 mg | 3 mL | 2000 mcg/mL | 20 mcg | 10 units | 15 units |
| 15 mg | 3 mL | 5000 mcg/mL | 50 mcg | 4 units | 6 units |
How do I calculate my dose in units from the vial?
The math is a three-step process.
Step 1. Find the total mg of sermorelin in your vial. This is printed on the label.
Step 2. Note how many mL of bacteriostatic water you added or your pharmacy instructed you to add.
Step 3. Divide total mg by total mL, multiply by 1000 to convert to mcg per mL, then divide by 100 to get mcg per syringe unit.
Formula: mcg per unit = (vial mg divided by mL added) times 10
To find your unit draw: desired mcg divided by mcg per unit = units to draw.
Example: 3 mg vial, 3 mL bacteriostatic water added. Concentration = 1 mg/mL = 1000 mcg/mL = 10 mcg per unit. For 300 mcg, draw 30 units.
What dose range do clinicians actually use?
The original FDA-approved indication for sermorelin acetate (brand name Geref, now discontinued) was treatment of idiopathic growth hormone deficiency in children. The labeled pediatric dose was 0.03 mg/kg per day administered subcutaneously at bedtime.
Adult compounding protocols, which are entirely off-label, commonly fall in the following ranges based on published case series, clinical practice surveys, and the limited available literature:
| Use Context | Typical Dose Range (mcg/day) | Typical Timing | Evidence Basis |
|---|---|---|---|
| Adult GH optimization (off-label) | 200 to 300 mcg | Once nightly at bedtime | Expert consensus, low-quality observational data |
| Higher-end adult protocols | 300 to 500 mcg | Once nightly or split BID | Anecdotal clinical practice; no RCT support |
| Pediatric GH deficiency (original label) | 0.03 mg/kg/day (weight-based) | Once nightly | FDA labeling, Serono clinical program data |
| Diagnostic stimulation test | 1 mcg/kg IV bolus (single use) | Single morning use | Endocrine Society guidelines (GH stimulation testing) |
Evidence ledger: what does the research actually support?
| Claim | Best Evidence Type | Effect Direction | Confidence |
|---|---|---|---|
| Sermorelin stimulates pituitary GH release acutely | Human pharmacokinetic/pharmacodynamic studies (small N) | Positive, consistent | High (for mechanism) |
| Nightly subcutaneous sermorelin raises IGF-1 in GH-deficient children | Controlled clinical trials supporting FDA approval (Geref, Serono) | Positive | Moderate to High (in pediatric GH deficiency) |
| Sermorelin improves body composition in healthy aging adults | Small observational studies and case series | Trend positive | Low |
| Sermorelin improves sleep quality | Mechanistic rationale plus small studies; no dedicated RCT | Plausible, unconfirmed | Very Low |
| Sermorelin is safer than exogenous GH for long-term use | Mechanistic argument (preserves pituitary feedback); no long-term comparative RCT | Plausible | Very Low |
| Doses above 500 mcg/day produce greater GH elevation than 200 to 300 mcg | No published dose-escalation RCT in adults | Unknown | Very Low |
| Bedtime dosing produces greater GH response than morning dosing | Physiological rationale (pulsatile GH secretion circadian pattern) plus small pharmacology studies | Positive (indirect) | Low to Moderate |
How does sermorelin work and what do the numbers say?
Sermorelin is a synthetic 29-amino-acid peptide corresponding to the first 29 amino acids of endogenous growth hormone-releasing hormone (GHRH), which itself is a 44-amino-acid hypothalamic peptide. The biologically active binding domain of GHRH resides in the first 29 residues, which is why the truncated sermorelin molecule retains full agonist activity at the GHRH receptor (GHRHR), a class B G-protein-coupled receptor.
Binding to GHRHR activates adenylyl cyclase, raises intracellular cyclic AMP, and triggers calcium-dependent exocytosis of pre-formed GH granules from somatotroph cells in the anterior pituitary. This is a physiologic, pulsatile mechanism, distinct from directly injecting exogenous recombinant GH.
Key pharmacokinetic facts from published literature:
- Plasma half-life after subcutaneous injection: approximately 10 to 20 minutes (reported in early Serono pharmacokinetic work supporting Geref approval).
- Peak GH response: typically occurs within 20 to 60 minutes of injection in responsive subjects.
- The brief half-life means sermorelin does not accumulate; it triggers a pulse and is cleared. This is the physiological rationale for the pulsatile dosing strategy.
What the mechanism does NOT prove: A GH pulse in the bloodstream does not automatically translate to meaningful changes in body composition, bone density, or metabolic outcomes at the doses used in adult compounding protocols. The pediatric indication involved documented GH deficiency. Extrapolating to aging adults with low-normal GH involves an evidence gap that mechanism alone cannot bridge.
What most sermorelin pages get wrong
Most content about sermorelin dosing in units makes two errors that can genuinely mislead patients.
Error 1: Treating units as universal. Content that says "inject 20 units per day" without specifying the vial concentration is incomplete and potentially dangerous. The same unit draw can represent a two-fold or greater difference in actual peptide mass depending on reconstitution. This is not a minor technicality; it is the entire dosing calculation.
Error 2: Conflating the pediatric approval with adult benefit. Sermorelin was FDA-approved for children with diagnosed GH deficiency. That approval does not establish efficacy or optimal dosing in healthy adults seeking body composition changes or anti-aging effects. These are different populations, different baseline GH axes, and the evidence base for the adult use case is genuinely thin. Presenting the FDA approval as validation of adult wellness dosing is a category error.
Error 3: Omitting purity and sourcing reality. Compounded sermorelin is not regulated with the same rigor as an FDA-approved finished drug. Certificate of analysis data from the compounding pharmacy matters. Peptide purity (high-performance liquid chromatography confirmed), sterility testing, and endotoxin limits are not guaranteed unless specified on the COA. A vial labeled "sermorelin 3 mg" with no COA gives you no information about actual peptide content or impurity profile.
When should the dose be taken and why does timing matter?
The standard recommendation is injection 30 to 60 minutes before sleep, on an empty stomach. Here is the physiological logic.
Endogenous GH secretion follows a circadian pattern with the largest pulse occurring during the first episode of slow-wave (stage 3) sleep, typically 60 to 90 minutes after sleep onset. Sermorelin's 10 to 20 minute half-life means the peptide is cleared quickly, but the GH pulse it triggers can overlap constructively with the natural sleep-associated surge if timed correctly.
The empty-stomach recommendation is also mechanism-based. Elevated insulin levels (postprandial state) suppress GH secretion through somatostatin feedback. Injecting sermorelin in a fed state may blunt the pituitary response. While this specific interaction has not been tested in a large sermorelin RCT, the insulin-GH axis relationship is well established in endocrinology literature, making the recommendation pharmacologically rational even if the magnitude of the interaction at these doses is unknown.
Honest head-to-head: sermorelin vs. alternatives
| Compound | Mechanism | Best Evidence | FDA Status | Typical Dose | Where Sermorelin Loses |
|---|---|---|---|---|---|
| Sermorelin | GHRH receptor agonist (29-AA fragment) | Small observational studies in adults; RCT only in pediatric GH deficiency | Discontinued (Geref); compounded off-label | 200 to 300 mcg/day SC | Evidence quality, manufacturing oversight |
| Tesamorelin | GHRH receptor agonist (full 44-AA, stabilized with trans-3-hexenoic acid) | Multiple Phase III RCTs (Falutz et al., 2010, NEJM); FDA-approved for HIV lipodystrophy | FDA-approved (Egrifta) | 2 mg/day SC | Cost, availability outside approved indication |
| Ipamorelin | Ghrelin receptor (GHSR) agonist; GH secretagogue via different receptor | Animal and small human data; no large RCT | Not approved; compounded | 200 to 300 mcg/day SC | Even less human RCT data than sermorelin |
| CJC-1295 (with DAC) | Long-acting GHRH analog; half-life extended to days via drug affinity complex | One small human study (Jetté et al., 2005, Growth Hormone IGF Research) | Not approved; compounded | 1 to 2 mg/week SC | Non-pulsatile exposure; theoretical receptor desensitization concern; minimal human safety data |
| Recombinant human GH (somatropin) | Direct GH replacement; bypasses pituitary | Extensive RCT data in GH-deficient adults; approved for multiple indications | FDA-approved (multiple brands) | Weight-based; typically 0.2 to 0.6 mg/day for adult GHD | Sermorelin wins only on cost and the theoretical argument about preserved feedback regulation |
Operational and label literacy: reading your vial and COA
When you receive a compounded sermorelin vial, five pieces of information must be present before you calculate a dose.
| What to Find | Where to Look | What It Tells You |
|---|---|---|
| Total peptide mass (mg) | Vial label | Essential for reconstitution math |
| Recommended reconstitution volume (mL) | Vial label or prescription insert | Sets your concentration; do not guess |
| HPLC purity (%) | Certificate of Analysis from compounding pharmacy | Should be 98% or higher for research-grade peptide |
| Sterility and endotoxin testing | COA | Required for injectable compounded preparations; absence is a red flag |
| Beyond-use date | Vial label | Reconstituted vials have a shorter beyond-use date than lyophilized powder |
If a product does not come with a COA or the pharmacy declines to provide one, that is a meaningful quality signal. USP 797 guidelines govern sterile compounding in the United States and set requirements for sterility testing, beyond-use dating, and environmental monitoring. Ask whether the compounding pharmacy operates under USP 797.
Stability and formulation: what degrades your peptide
This is the section most medspa blogs omit entirely.
Lyophilized (freeze-dried) sermorelin powder is far more stable than reconstituted solution. The lyophilization process removes water, which is the primary driver of hydrolytic degradation of peptide bonds. Once you add bacteriostatic water, a slow degradation clock starts.
Hydrolysis: Water molecules cleave amide bonds between amino acid residues. Rate accelerates with heat, extreme pH, and light exposure. Refrigeration at 2 to 8 degrees Celsius slows but does not eliminate this process.
Oxidation: Methionine and tryptophan residues (where present) are vulnerable to oxidative damage from exposure to air or light. Sermorelin's 29-amino-acid sequence does not contain methionine, which reduces but does not eliminate oxidation risk from other reactive residues.
Practical rules with chemical rationale:
- Store lyophilized vials in the freezer (minus 20 degrees Celsius) until ready to reconstitute. Cold temperature reduces Arrhenius reaction rates for hydrolysis.
- After reconstitution, refrigerate at 2 to 8 degrees Celsius. Use within the beyond-use date on the label, typically 28 to 30 days per USP 797 guidance for many compounded sterile preparations, though your pharmacy may specify a different window.
- Do not freeze reconstituted solution. Ice crystal formation can denature peptide structure.
- Keep vials away from direct light. UV photons carry enough energy to break certain amino acid side-chain bonds (particularly aromatic residues).
- Use bacteriostatic water (contains 0.9% benzyl alcohol) rather than sterile water for injection. Bacteriostatic water suppresses microbial growth over the multi-dose use period; sterile water does not, making contamination risk unacceptable for multi-dose vials.
A degraded vial may look normal. Clarity is not proof of potency. If your vial has been unrefrigerated for more than a few hours, or has been stored reconstituted for longer than the labeled beyond-use period, the actual peptide content is unknown.
FAQ
How many units of sermorelin per day is typical?
Most compounding protocols use 200 to 300 mcg per day injected subcutaneously at bedtime. On a standard 1 mg reconstituted in 2 mL bacteriostatic water vial, 200 mcg equals 40 units and 300 mcg equals 60 units on an insulin syringe. Units depend entirely on how the vial is reconstituted.
What does one unit of sermorelin actually mean?
One unit on a U-100 insulin syringe equals 0.01 mL of solution. The microgram dose per unit depends entirely on your reconstitution ratio. With 1 mg dissolved in 2 mL, each unit delivers 5 mcg. With 1 mg in 1 mL, each unit delivers 10 mcg.
What reconstitution math should I use for sermorelin?
Divide the total mg in the vial by the mL of bacteriostatic water added, then multiply by 1000 to get mcg per mL. Divide by 100 to get mcg per unit. Example: 3 mg in 3 mL = 1 mg/mL = 1000 mcg/mL = 10 mcg per unit.
Is 200 mcg or 300 mcg of sermorelin per day more effective?
There is no high-quality RCT directly comparing these doses in healthy adults for body composition outcomes. The original FDA-approved pediatric dose was 0.03 mg/kg/day. Adult compounding protocols typically fall between 200 and 500 mcg, but dose-response data in adults is limited to small or observational studies.
Should sermorelin be injected once or split into multiple doses per day?
Most protocols use a single dose at bedtime to align with the natural pulsatile GH surge during slow-wave sleep. Some providers split doses, but there is no robust human data showing split dosing is superior to a single nocturnal injection for GH secretagogue effects.
How long does sermorelin stay active after injection?
Sermorelin has a short plasma half-life, reported in pharmacokinetic studies at roughly 10 to 20 minutes after subcutaneous injection. GH pulse effects last longer than the peptide itself due to downstream signaling, but the compound is cleared rapidly.
How do units of sermorelin compare to units of other peptides like ipamorelin?
Units are not interchangeable between peptides. Ipamorelin is typically dosed at 200 to 300 mcg per injection, similar in microgram terms, but it acts on ghrelin receptors rather than GHRH receptors. The unit count on the syringe depends on reconstitution of each individual vial, not on the peptide name.
Can I take more than 500 mcg of sermorelin per day?
Higher doses are used in some protocols but carry greater risk of side effects including injection site reactions, flushing, headache, and potential receptor desensitization with chronic supraphysiologic stimulation. There is no strong human evidence that doses above 500 mcg per day produce proportionally greater benefit.
How do I know if my sermorelin vial is still good?
Reconstituted sermorelin should be clear and colorless. Cloudiness, visible particles, or a yellow tint suggest degradation or contamination. Once reconstituted with bacteriostatic water, vials are typically used within 30 days when refrigerated. Peptide bonds are susceptible to hydrolysis over time at room temperature.
Does sermorelin require cycling or can it be used continuously?
The original FDA indication for sermorelin acetate (Geref) was continuous nightly dosing in children with GH deficiency. Adult compounding protocols vary widely, with some providers recommending 5-days-on, 2-days-off schedules to reduce tachyphylaxis risk, though controlled evidence for this strategy is lacking.
How does sermorelin compare to tesamorelin or CJC-1295 on a per-dose basis?
Tesamorelin has a large Phase III RCT dataset (Falutz et al., 2010) supporting 2 mg/day for visceral fat reduction in HIV-associated lipodystrophy, an FDA-approved indication. CJC-1295 and sermorelin lack equivalent RCT evidence. On evidence quality, tesamorelin is clearly superior despite similar mechanisms.
Sources
- U.S. Food and Drug Administration. Geref (sermorelin acetate) Prescribing Information. Serono Laboratories. FDA approval documentation (pediatric GH deficiency indication).
- Falutz J, Mamputu JC, Potvin D, et al. Effects of tesamorelin, a growth hormone-releasing factor analog, in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial with a safety extension. Journal of Acquired Immune Deficiency Syndromes. 2010;53(3):311-322.
- Jetté L, Harvey L, Eugster K, Bhatt P. GH-releasing factor analog (CJC-1295) increases GH secretion in rats without significant tachyphylaxis. Growth Hormone and IGF Research. 2005;15(6):394-399.
- Thorner MO, Vance ML, Laws ER Jr, Horvath E, Kovacs K. The anterior pituitary. In: Wilson JD, Foster DW, Kronenberg HM, Larsen PR, eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia: Saunders; 1998. (GH pulsatile secretion and circadian regulation).
- Van Cauter E, Plat L, Copinschi G. Interrelations between sleep and the somatotropic axis. Sleep. 1998;21(6):553-566. (Slow-wave sleep and GH secretion).
- Corpas E, Harman SM, Pineyro MA, Roberson R, Blackman MR. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. Journal of Clinical Endocrinology and Metabolism. 1992;75(2):530-535.
- United States Pharmacopeia. USP Chapter 797: Pharmaceutical Compounding - Sterile Preparations. Current edition. (Beyond-use dating, sterility requirements).
- Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clinical Interventions in Aging. 2006;1(4):307-308.
- Endocrine Society Clinical Practice Guideline. Evaluation and Treatment of Adult Growth Hormone Deficiency. Journal of Clinical Endocrinology and Metabolism. 2011;96(6):1587-1609.