"Growth hormone peptides" get a lot of attention online, often with big promises about muscle, fat loss and youth. This guide explains what growth hormone secretagogues actually are, how the main groups differ, and what is and is not supported by evidence.
Key takeaways
- A secretagogue is something that makes a gland release a hormone. GH secretagogues signal the pituitary to release growth hormone (GH).
- There are two main families: GHRH analogs (like tesamorelin and sermorelin) and ghrelin-receptor agonists (like ipamorelin, GHRP-2, GHRP-6 and MK-677).
- Only a few are FDA-approved, and only for narrow uses. Most sold online are not approved.
- Known concerns include higher blood sugar, fluid retention and unknown long-term effects. Human research is mostly small and short.
- All are banned in tested sports under the WADA Prohibited List.
How growth hormone is normally controlled
Growth hormone is made by the pituitary gland at the base of your brain. It is released in pulses, mostly during deep sleep. GH then tells the liver to make IGF-1 (insulin-like growth factor 1), which carries out many of GH's effects on tissues.
Two natural signals control the pulses:
- GHRH (growth hormone-releasing hormone) from the hypothalamus says "release GH."
- Ghrelin, a hormone made mostly in the stomach, also boosts GH release and increases hunger.
A third signal, somatostatin, puts on the brakes. Your body balances these signals all day. Our IGF-1 basics guide explains why doctors measure IGF-1 to see how this system is working.
The two main families
GHRH analogs
These are lab-made versions of GHRH or its active piece. They act on the GHRH receptor in the pituitary.
- Tesamorelin: FDA-approved for one specific use (see below).
- Sermorelin: was FDA-approved in the past but the brand was discontinued.
- CJC-1295: a longer-acting analog that was studied but never approved.
Ghrelin-receptor agonists
These act on the growth hormone secretagogue receptor, the same receptor ghrelin uses. Many of them were called "GHRPs" (growth hormone-releasing peptides).
- GHRP-2, GHRP-6, hexarelin: short peptides studied mostly in the 1990s and 2000s.
- Ipamorelin: a newer GHRP designed to be more selective.
- MK-677 (ibutamoren): a pill that acts on the same receptor. It is not a peptide at all. See our post on whether MK-677 is really a peptide.
- Macimorelin: an oral agent approved only as a diagnostic test.
A 2018 review in Sexual Medicine Reviews explained that the two families work through different receptors and can act together, which is why online marketing often pairs one of each.
What is actually FDA-approved
| Substance | Family | FDA status (Oct 2026) |
|---|---|---|
| Tesamorelin (Egrifta WR) | GHRH analog | Approved to reduce excess abdominal fat in adults with HIV and lipodystrophy |
| Macimorelin (Macrilen) | Ghrelin-receptor agonist | Approved to help diagnose adult GH deficiency |
| Sermorelin (Geref) | GHRH analog | Previously approved; discontinued by the maker, approval withdrawn in 2009 |
| CJC-1295, ipamorelin, GHRP-2, GHRP-6, hexarelin | Various | Not FDA-approved |
| MK-677 (ibutamoren) | Ghrelin-receptor agonist (non-peptide) | Not FDA-approved |
None of these are approved for anti-aging, bodybuilding or general weight loss. Use of these products outside a labeled use is either off-label use of an approved drug (a prescriber's decision) or use of an unapproved substance.
The FDA has also flagged several of them for compounding safety concerns. Its list of bulk substances that "may present significant safety risks" includes ipamorelin, GHRP-2, GHRP-6 and ibutamoren, with concerns ranging from immune reactions and impurities to blood sugar effects and, for ibutamoren, a possible heart failure signal.
What the research shows
Studies do show that secretagogues raise GH and IGF-1 levels. Some studies found increases in lean body mass, changes in sleep, and more appetite. But the same 2018 review noted that most trials were small and short, that functional benefits were often modest, and that long-term safety, including cancer risk, has not been studied well.
That gap matters. Raising GH and IGF-1 above the normal range is not automatically good. People with naturally very high GH (a condition called acromegaly) have real health problems, which is why doctors keep IGF-1 in an age-appropriate range when treating with GH.
Known risks and side effects
Reported concerns across this class include:
- Higher blood sugar and lower insulin sensitivity, the most consistent finding
- Fluid retention and swelling, joint pain and tingling in the hands
- Increased appetite, especially with ghrelin-like agents
- Temporary rises in cortisol and prolactin with some GHRPs
- Heart failure signal: one hip fracture trial of MK-677 in older adults was stopped early partly over this concern
- Product quality risks with unapproved products, including contamination and wrong amounts
People with diabetes, a history of cancer, heart disease or pituitary problems face extra questions. The tesamorelin label, for example, lists active cancer and pregnancy as reasons not to use it.
Questions to ask your provider
If you are curious about any of these, a licensed provider can help you weigh it. Useful questions:
- Do I have a medical reason, such as a diagnosed GH deficiency?
- What do my IGF-1 and blood sugar labs look like now?
- Is the product FDA-approved for my situation, and if not, what does that mean for me?
- How would we monitor for side effects?
Our telehealth guide covers how to find a licensed provider, and you can read the profile for tesamorelin for more on the one approved GHRH analog.
Sports and testing
The 2026 WADA Prohibited List bans GH, GHRH and its analogs (naming CJC-1295, sermorelin and tesamorelin), GH secretagogues (including ibutamoren) and GHRPs (including GHRP-2, GHRP-6 and hexarelin) at all times. Athletes who are tested should assume every product in this family is prohibited.
The bottom line
Growth hormone secretagogues push your own body to release more GH. They are real biology, but most are not FDA-approved, human data is limited, and blood sugar and long-term safety are open questions. If GH is on your mind, start with a provider and a lab test rather than a product.
Sources
- Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev. 2018
- EGRIFTA WR (tesamorelin) prescribing information, DailyMed
- MACRILEN (macimorelin) prescribing information, DailyMed
- FDA: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks
- World Anti-Doping Agency: The Prohibited List (2026)
Frequently asked questions
Are growth hormone secretagogues the same as growth hormone?
No. Growth hormone is the hormone itself. Secretagogues are substances that signal your pituitary gland to release more of your own growth hormone. They still raise GH and IGF-1 levels, so they carry some of the same concerns.
Which growth hormone secretagogues are FDA-approved?
Very few, and only for narrow uses. Tesamorelin (Egrifta WR) is approved to reduce excess belly fat in adults with HIV-associated lipodystrophy, and macimorelin (Macrilen) is approved as a test to help diagnose adult growth hormone deficiency. Most others sold online are not FDA-approved.
Are GH secretagogues allowed in sports?
No. The 2026 World Anti-Doping Agency Prohibited List bans growth hormone releasing factors, including GHRH analogs, GH secretagogues and GHRPs, at all times for athletes covered by the code.