Key Takeaways
- All three prompt your pituitary gland to release its own growth hormone. None of them is growth hormone itself.
- Sermorelin and tesamorelin act on the same receptor, the one for growth hormone-releasing hormone (GHRH). Ipamorelin works through the ghrelin receptor instead.
- In a small study, older men's growth hormone and IGF-1 levels rose after 14 days of GHRH injections at the higher dose tested.
- Tesamorelin is best known for its trial results in adults with HIV-associated lipodystrophy.
- LIV offers sermorelin, not tesamorelin or ipamorelin.
Growth hormone release changes a lot with age. In one study of healthy men, growth hormone secretion dropped roughly 75% between young adulthood (ages 16 to 25) and midlife (ages 36 to 50). Deep, slow-wave sleep fell from nearly 20% of the night before age 25 to under 5% after 35. Each of the three prompts your body to release its own growth hormone, and they differ in how they do it and what they're known for.
How They Work
All three work through the system your body already uses to control growth hormone release. Part of that system is growth hormone-releasing hormone, a signal from your hypothalamus. It tells your pituitary to make your own growth hormone and release it in bursts rather than a steady stream, as tesamorelin's approved labeling describes it.
The Three, Side by Side
Sermorelin: an analog of naturally occurring growth hormone-releasing hormone, specifically growth hormone releasing factor 1-29 NH2-acetate. It's the working end of the natural hormone, and it binds the same pituitary receptors. Somatostatin, your body's own brake, still keeps it in check. Your growth hormone comes in bursts, rather than at the constant level injected growth hormone gives (Walker, Clinical Interventions in Aging, 2006).
Tesamorelin: the same receptor, a bigger molecule. Its approved labeling describes it as the 44 amino acids of human GRF, the body's own growth hormone-releasing hormone, plus a six-carbon chain attached at one end. In lab testing, it binds and stimulates human GRF receptors with potency similar to the body's own GRF.
Ipamorelin: a different door into the same room. It's a synthetic five-amino-acid peptide that acts like ghrelin, activating ghrelin receptors in the hypothalamus and on the pituitary rather than the GHRH receptor. It was introduced in 1998 as the first selective growth hormone secretagogue. It earned that name by releasing growth hormone without raising cortisol or ACTH, the pituitary signal that triggers cortisol. GHRP-6 and GHRP-2, the compounds it was derived from, raised both. FDA's 2024 review describes the same profile.
WHAT SEPARATES THEM
Two act on one receptor. The third does not.
| Sermorelin | Tesamorelin | Ipamorelin | |
|---|---|---|---|
| Receptor it acts on | GHRH receptor | GHRH receptor | Ghrelin receptor |
| Primary focus | Supports the pituitary's own GH release | Excess abdominal fat, HIV lipodystrophy | No established use |
| Potency, as a source states it | Not established in any head-to-head | Similar to your own GHRH, per its label | Similar to GHRP-6, in animals |
| FDA status | Approved product discontinued 2008 | Approved and marketed | No approved product |
Sermorelin is the one LIV supplies.
Key Differences and Uses
| Sermorelin | Tesamorelin | Ipamorelin | |
|---|---|---|---|
| What it is | GHRH analog, the 1-29 fragment | GHRH analog, 44 amino acids plus a hexenoyl chain | Synthetic five-amino-acid peptide that acts like ghrelin |
| Receptor | GHRH receptor | GHRH receptor | Ghrelin receptor |
| Primary focus | Supports the pituitary's own growth hormone release | Reduction of excess abdominal fat in adults with HIV-associated lipodystrophy | No established use. Its one published efficacy trial was in postoperative ileus |
| Potency, from a source | Not established in any head-to-head | Similar to the body's own GRF, per its labeling | Similar to GHRP-6 in rat and swine models |
| Half-life, from a source | Not stated in these sources | 11 minutes | Not stated in these sources |
| Study results | Small studies in older adults: hormone levels at 2 weeks, thinking tests at 6 months | 26-week trials: visceral fat down 18% and 14% | Its one published efficacy trial missed its endpoints |
| Effect on cortisol | Not characterized here | Not characterized here | No significant rise, the finding it's known for |
| Available from LIV | Yes, if your provider prescribes it | No | No |
What Sermorelin May Help With
In a small study, older men's growth hormone and IGF-1 levels rose after 14 days of GHRH injections at the higher dose tested. In a six-month study, older adults did better on tests of thinking and attention after sermorelin injections.
How Do Their Half-Life and Potency Compare?
Of the three, only tesamorelin has a half-life stated in these sources, and no head-to-head trial ranks their potency.
Half-life: tesamorelin's labeling reports that its level in the blood halves in 11 minutes, on average, after a single dose under the skin in healthy volunteers. That's short, like the natural hormone it's modeled on.
Potency: tesamorelin's label compares it with your own hormone, not with sermorelin or ipamorelin. What tesamorelin does have is controlled trial results in its approved population.
What Tesamorelin's Trials Found
In two 26-week controlled trials of tesamorelin in adults with HIV-associated lipodystrophy, visceral fat, the fat around the organs, fell by 18% in one study and 14% in the other, compared with small changes on placebo. People kept on treatment for a further 26 weeks held the reduction, and those switched to placebo rebounded.
How You and Your Provider Track Your Response
Under LIV's protocol, you'll have an IGF-1 blood test at 2 to 6 weeks, and your provider looks at the result alongside your sleep data and how you feel.
Your provider reviews your history before you start and checks in on you before each refill. LIV's protocol includes a planned pause, called a washout, intended to limit tolerance, and your provider will tell you when to take it. Check with your provider before changing your dose.
Which One Should You Consider?
If you're choosing through LIV, it's sermorelin. Tesamorelin is a brand-name prescription drug for a specific condition, and LIV doesn't offer it or ipamorelin. If sermorelin is right for you, a licensed provider prescribes it and a licensed pharmacy prepares it for you.
Bring your goals and questions, and your provider will help you decide whether sermorelin fits. When you're ready, start with an evaluation.
Related reading: What an evaluation covers · The NAD+ supplement guide
Frequently Asked Questions
What is the main difference between sermorelin and ipamorelin?
The receptor. Sermorelin is an analog of growth hormone-releasing hormone and binds the GHRH receptor. Ipamorelin is a five-amino-acid peptide that acts like ghrelin and binds the ghrelin receptor instead. Both lead to growth hormone release from the pituitary, by different routes.
Is tesamorelin stronger than sermorelin?
No study has compared them head to head. Tesamorelin's labeling describes its receptor potency as similar to the body's own GHRH. What sets it apart is controlled trial results in its approved population, adults with HIV-associated lipodystrophy.
Does ipamorelin really avoid raising cortisol?
In the 1998 study that introduced it, yes: it raised growth hormone without raising ACTH or cortisol, where GHRP-6 and GHRP-2 raised both. That work was done in swine. The prolactin claim often attached to it isn't a difference, because none of the compounds tested affected prolactin.
What did studies of sermorelin find?
In a small study, ten healthy older men (average age 68) received GHRH-(1-29) injections twice daily for 14 days at each of two doses, 0.5 mg and 1 mg. Their growth hormone and IGF-1 levels rose significantly only at the higher dose, 1 mg twice daily. These were hormone measurements, not a promise that symptoms improve in two weeks, and the study regimen isn't dosing advice. The study didn't test women or LIV's compounded preparation, and equivalent results aren't established for that preparation.
In a randomized, placebo-controlled study, 100 adults ages 60 to 85 started and 89 completed six months of injected sermorelin acetate (GEREF), initially 1 mg nightly, with dose adjustment in some participants. Improvements appeared on several cognitive tests and didn't depend on gender or estrogen status. This isn't evidence of dementia prevention, longer life or a percentage improvement in everyday memory.
Participants were older than the midlife group in the growth hormone study above, and the study didn't test adults ages 35 to 55. It used GEREF, not a compounded preparation.
Where do the growth hormone and sleep figures come from?
From a 2000 study in JAMA of 149 healthy, normal-weight men aged 16 to 83, combining sleep-laboratory data from four centers between 1985 and 1999. It's observational and included men only. The early-adulthood group was ages 16 to 25 and the midlife group ages 36 to 50. It describes how sleep and growth hormone change with age; it didn't test sermorelin and doesn't show that sermorelin restores deep sleep, growth hormone levels or any health outcome.
Will sermorelin work for me?
Your provider measures how you respond. LIV's protocol calls for an IGF-1 blood test at 2 to 6 weeks, reviewed alongside your sleep data and how you feel. A change in IGF-1 doesn't necessarily mean you'll notice a benefit, particularly if your level was already adequate. Your provider considers both your results and your experience when discussing whether to continue.
Is there an FDA-approved sermorelin?
Not on the market today. GEREF, a sermorelin acetate injection, was an FDA-approved product that its sponsor discontinued in December 2008, and FDA later determined it wasn't withdrawn from sale for reasons of safety or effectiveness. Through LIV, sermorelin is compounded: a licensed pharmacy prepares it specifically for you. The FDA doesn't approve compounded medicines for safety, quality or how they're made.
Why doesn't LIV offer tesamorelin?
Tesamorelin is FDA-approved as a brand-name drug, EGRIFTA, for reducing excess abdominal fat in adults with HIV-associated lipodystrophy, as its prescribing information states. LIV doesn't offer care for that use.
Why doesn't LIV offer ipamorelin?
FDA lists ipamorelin acetate among bulk drug substances that may present significant safety risks in compounding by outsourcing facilities, an entry dated September 29, 2023. FDA says compounded drugs containing it may pose a risk of immune reactions when given by certain routes, due to possible aggregation or peptide-related impurities. It adds that ipamorelin's unnatural amino acids make the peptide harder to characterize.
FDA also cites a published study that identified serious adverse events, including death, when ipamorelin was given intravenously to improve gastric motility. For certain other injectable routes, FDA says it hasn't identified safety information, so it lacks enough information to know whether the drug would cause harm by those routes.
References
Corpas, E., Harman, S. M., Piñeyro, M. A., Roberson, R., & Blackman, M. R. (1992). 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, 75(2), 530-535. https://pubmed.ncbi.nlm.nih.gov/1379256/
Federal Register. (2013). Determination that GEREF (sermorelin acetate) injection and GEREF Diagnostic were not withdrawn from sale for reasons of safety or effectiveness, 78 FR 14104, March 4, 2013. Cited by name; the Federal Register page could not be retrieved automatically.
Raun, K., Hansen, B. S., Johansen, N. L., Thøgersen, H., Madsen, K., Ankersen, M., & Andersen, P. H. (1998). Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 139(5), 552-561. https://pubmed.ncbi.nlm.nih.gov/9849822/
Theratechnologies Inc. (2025). EGRIFTA WR (tesamorelin) for injection, for subcutaneous use: Prescribing information. DailyMed, U.S. National Library of Medicine. SPL set id 839334d3-8c1d-4c26-9036-2ab524a6ea75, SPL version 2, revised March 2025. Sections 1, 11, 12.1, 12.3 and 14. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75
U.S. Food and Drug Administration. (2023). Certain bulk drug substances for use in compounding that may present significant safety risks, ipamorelin acetate entry, September 29, 2023. Read October 1, 2026. https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
U.S. Food and Drug Administration. (2024). FDA briefing document, Pharmacy Compounding Advisory Committee meeting, October 29, 2024: ipamorelin-related bulk drug substances. https://www.fda.gov/media/182088/download
Van Cauter, E., Leproult, R., & Plat, L. (2000). Age-related changes in slow wave sleep and REM sleep and relationship with growth hormone and cortisol levels in healthy men. JAMA, 284(7), 861-868. https://jamanetwork.com/journals/jama/fullarticle/192981
Vitiello, M. V., Moe, K. E., Merriam, G. R., Mazzoni, G., Buchner, D. H., & Schwartz, R. S. (2006). Growth hormone releasing hormone improves the cognition of healthy older adults. Neurobiology of Aging, 27(2), 318-323. https://faculty.washington.edu/vitiello/Recent%20Publications/GHRH%20and%20Cognition%20in%20Aging.pdf
Walker, R. F. (2006). Sermorelin: A better approach to management of adult-onset growth hormone insufficiency? Clinical Interventions in Aging, 1(4), 307-308. https://pmc.ncbi.nlm.nih.gov/articles/PMC2699646/
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