Growth hormone secretagogues: what are they? | HRTGuru (2023)

In this article

  • 1 What stimulates growth hormone secretion?
  • 2 What are growth hormone secretagogues?
    • 2.1 Benefits of growth hormone secretagogues
    • 2.2 Adverse effects of growth hormone secretagogues
  • 3 What is the difference between HGH and peptides?
  • 4 Are HGH Peptides Legal and Safe?

If you're looking for ways to improve various health conditions or your overall well-being, you may have come across drugs called growth hormone secretagogues (GHSs) or "peptides."

GHS are a group of compounds, including peptides and other non-peptide molecules, that can effectively stimulate your natural human growth hormone (HGH) synthesis.

HGH is quite a popular hormone among bodybuilders thanks to its powerful fat burning and anabolic benefits. Because of this, boosting natural HGH production in some way is a widely desired effect for people looking to improve their physiques.

However, keep in mind that while some GHS are FDA-approved, many of these drugs are understudied and long-term data on their safety and effectiveness is lacking.

Read on to discover the answers to any questions you might have about these substances, including how GHS are researched and what to expect in terms of benefits and side effects based on the evidence.

What stimulates growth hormone secretion?

The pituitary gland is the only gland in the human body that can produce HGH. This synthesis is regulated by several other hormones, but primarily by two of the hormones produced by the hypothalamus - growth hormone-releasing hormone (GHRH) and somatostatin.

GHRH is the main factor that stimulates pulsatile GH secretion in the pituitary gland by activating the GHRH receptor. On the other hand, somatostatin has counter-regulatory effects and limits HGH synthesis.

In addition, both the pituitary gland and the hypothalamus have so-called ghrelin receptors (GR). Ghrelin is known as the hunger hormone because the digestive system produces it to stimulate hunger and appetite via the GR in the hypothalamus.

But activation of the GR in the pituitary gland also stimulates the release of HGH. Therefore theNatural HGH secretion often increases during fasting, and the hormone helps maintain stable blood sugar levels during this period.

(Video) What Are Growth Hormone Releasing Secretagogues? Dr. Rand McClain

In contrast, eating foods with protein or carbohydrates lowers ghrelin levels and increases insulin secretion, which suppresses HGH synthesis.

What are growth hormone secretagogues?

GHS are substances that mimic the function of either GHRH or ghrelin and trigger the appropriate receptors - the GHRH receptor and the GR. The latter is also known as Growth Hormone Secretagogue Receptor (GHSR).

Triggering these receptors in the pituitary gland results in the release of HGH. Depending on which receptor they trigger, GHSs can be classified into 2 main groups – GHRH analogues and ghrelin mimetics.

GHRH-Analogs are:

  • Sermorelin (GRF 1-29)
  • Modified GRF 1-29
  • Tesamorelin

All GHRH analogues are injectable as the human gastrointestinal tract can easily destroy their peptide structure.

Ghrelin mimetics are (non-exhaustive list):

  • Pralmorelin (GHRP-2)
  • GHRP-6
  • Ipamorelin
  • Ibutamoren (MK-677)
  • Anamorelin
  • Macimorelin

In addition, ghrelin mimetics can be divided into orally active and injectable. The group of orally active ghrelin mimetics includes several peptides as well as all non-peptide mimetics.

Injectable GHS are taken subcutaneously because this method is safe, effective, and easy to perform by untrained individuals. Besides, it also allows for a slower release of the drug, thereby increasing its half-life.

The duration of action depends on the half-life of the secretagogue and varies from 10 minutes to 7 hours. Normally, the peak of HGH levels occurs 30-60 minutes after administration and lasts 2-8 hours.

Effects of GHS therapy come on relatively slowly. Depending on the GHS,study reportBenefits after at least 2-4 months of use. Additionally, due to their short half-life, most secretagogues require multiple administrations per day, meaning you may have to undergo multiple sub-Q injections throughout the day.

Keep in mind that both GHRH analogs and ghrelin mimetics cannot increase your natural HGH synthesis beyond their physiological limits, which are controlled by somatostatin.

(Video) Growth Hormone Secretagogue Peptides | DailyDocTalk 82

Benefits of growth hormone secretagogues

Most GHS are designed to diagnose growth hormone deficiency (GHD), treat growth retardation in children, or treat conditions associated with various wasting conditions such as HIV and cancer.

Growth hormone secretagogues: what are they? | HRTGuru (1)

The main benefits of GHS include increasing the frequency and amplitude of HGH pulses. In addition, IGF-1 synthesis, which is the main mediator of HGH's anabolic effects, also increases during GHS therapy.

Studies in the Seniors Reportthat 1-2 weeks of therapy raises IGF-1 levels into the normal range for young adults.

GHS are also often used by athletes and bodybuilders aiming to boost fat loss and improve their overall physique. Still, current evidence doesn't support the effectiveness of most GHSs in enhancing weight loss.

Currently, only the GHRH analogue tesamorelin has been consistently shown to reduce the amount of visceral fat when administered to HIV patients. The other GHRH analogue, Sermorelin, appears to increase lean body mass without affecting fat mass.according to the research results.

For example, studies of ibutamoren in younger and older individuals report a 5-7 pound increase in lean body mass without compromising fat mass. On the other hand, Anamorelin administration has been shown to increase both lean mass and fat mass in patients with cancer-related cachexia.

studieson ibutamoren show that this ghrelin mimetic can also improve sleep quality by increasing the duration of REM sleep in both younger and older individuals.

In addition, ibutamoren has shown potential benefits for improving bone health and recovery in elderly patients with fractures, but was discontinued due to the potential risk of heart failure.

Ghrelin mimetics have also been studied for potential benefits in gastrointestinal dysfunction. So far, all GHS except Relamorelin have not shown sufficient efficacy. Relamorelin is still in phase 3 clinical trials for the treatment of diabetic gastroparesis.

Side effects of growth hormone secretagogues

Side effects of GH secretagogues can include water retention, headaches, edema, high blood sugar, food cravings, increased appetite, and weight gain.

(Video) Growth Hormone Secretagogues

But more importantly, GHS are not effective in treating adults with GHD because the pituitary gland's capacity to produce HGH is significantly reduced in these patients. Scientists report that peak HGH levels tend to remain lower in GHD patients treated with GHS compared to healthy controls.

However, GHRH analogs are fairly well tolerated, and the most common side effects are a transient increase in water retention, edema, headache, muscle and joint stiffness, high blood sugar. In addition, ghrelin mimetics can even lead to significant weight gain, since activation of the ghrelin receptor also increases appetite.

Therefore, the effects of ghrelin mimetics can vary from increasing lean body mass with no effect on fat to increasing both fat and muscle mass. Many ghrelin mimetics are not selective over HGH synthesis, which can also lead to increases in other hormones such as adrenocorticotropic hormone (ACTH), cortisol, and prolactin.

What is the difference between HGH and peptides?

While GHS stimulate the natural production of growth hormone by the pituitary gland, HGH therapy involves the administration of exogenous growth hormone, which is identical in structure to the endogenous one.

Therefore, HGH therapy is much more reliable in increasing growth hormone levels in individuals with pituitary dysfunction compared to GHS. HGH treatment is also currently the only FDA-approved therapy for GHD.

HGH therapy can successfully treat all symptoms of GHD, and the first benefits usually appear after the first month of treatment.

Your natural HGH production is limited by regulatory hormones like somatostatin. Therefore, even in healthy individuals, GHS are not as effective in increasing HGH levels as exogenous growth hormone injections.

The effects of HGH injections on body composition also kick in faster as it is much easier to regulate the HGH dose and therefore the levels of growth hormone in your body.

HGH therapy has also been studied much more thoroughly and there is no risk of unexpected side effects seen with GHSs.

Some patients may also consider taking both HGH therapy and GHS to maximize the benefits - rapid results within the first month of HGH treatment and additional benefits from GHS after 2-3 months.

However, simply increasing the dose of your HGH regimen with your doctor's approval would have similar or better effects without the risk of unexpected side effects.

(Video) Growth Hormone Secretagogues & Tissue Healing

Also, taking HGH injections does not suppress the functioning of the pituitary gland. This is also one of the most importantDifferences between HGH and steroids, which are known to suppress the normal function of the male testicles.

Are HGH Peptides Legal and Safe?

All HGH peptides were originally developed by pharmaceutical companies for the treatment or diagnosis of various medical conditions. However, not all have been approved by the FDA, while others have been discontinued after approval.

Additionally, although most GHS are not controlled substances, a prescription is required for purchase.

There is currently no evidence that legal GHS can increase the risk of other chronic diseases such as type 2 diabetes or cancer.

According to the latest reviewspublished in the scientific community, GHSs have not promised much in the treatment of gastrointestinal diseases and GHD. However, some GHS appear to be safe and effective options for body composition management in chronic diseases.

The FDA has approved Sermorelin for the management of brief statistics in children and the diagnosis of GHD. EMD Serono initially made it but then discontinued it due to production issues. It is currently available as a generic.

The FDA has approved tesamorelin for the treatment of excess abdominal fat in HIV-infected patients with lipodystrophy. It is manufactured by the Canadian company Theratechnologies.

Several ghrelin mimetics currently have investigational drug status, and some have applied for FDA approval.

Anamorelin is manufactured by Japan-based Ono Pharmaceuticals and is currently being studied for the treatment of cachexia in lung cancer patients.

While most GHSs appear to have an excellent safety profile, some ghrelin mimetics such as ibutamoren have been discontinued due to a possible association between the drug and the onset of heart failure.

Ipamorelin has also been discontinued due to its lack of effectiveness in improving recovery after bowel surgery.

(Video) Human Growth Hormones, Secretagogues, and why they matter

GHRP-6 and GHRP-2 (Pralmorelin) are also currently unapproved by the FDA. Therefore, these products are not manufactured by any disgruntled pharmaceutical company in the US and all products available online are illegal. Also, there is no guarantee of their quality and safety.


What are growth hormone releasing secretagogues? ›

Growth hormone secretagogues (GHS) are synthetic, non-natural peptidyl and non- peptidyl molecules. GH-releasing peptides (GHRPs), the first component of the GHS family, were invented rather than isolated in 1977, and are endowed with strong GH-releasing effect both in animals and in humans (1–4).

What is the best HGH secretagogue? ›

Tesamorelin is currently the most effective HGH secretagogue in the market that is proven to increase IGF-1 levels and reduce visceral fat.

Do growth hormone secretagogues work? ›

To date, few long-term, rigorously controlled studies have examined the efficacy and safety of GHSs, although GHSs may improve growth velocity in children, stimulate appetite, improve lean mass in wasting states and in obese individuals, reduce bone turnover, increase fat-free mass, and improve sleep.

What are growth hormones answer the following? ›

Growth hormone is a peptide hormone that stimulates growth, development and regeneration. This peptide hormone is made up of 191 amino acids that form a long, single-chain polypeptide. Growth hormone is synthesized in the somatotropic cells, which are found in the anterior pituitary gland.

What are the side effects of growth hormone secretagogue? ›

Common side effects of GH replacement include fluid retention, with peripheral edema (40% of patients), arthralgias (20% of patients), and carpal tunnel syndrome (10% of patients) (Anawalt and Merriam 2001; Cummings and Merriam 2003; Merriam and Cummings 2003). Studies have also shown increased fasting glucose levels.

What are the side effects of secretagogue? ›

The main side effects of insulin releasing pills (Secretagogues) (SFUs and glinides) are low blood sugars (hypoglycemia) and weight gain. If you have liver or kidney problems, you may not be able to take these medicines.

Is MK-677 a growth hormone secretagogue? ›

MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.

What does secretagogue do? ›

A secretagogue is an agent that promotes the secretion of hormones, neurohormones, chemical neurotransmitters, enzymes, or other molecules synthesized and secreted by cells.

How effective is growth hormone treatment? ›

There's little evidence to suggest HGH can help otherwise healthy adults regain youth and vitality. Alternatively, HGH treatments may increase the risk of other medical conditions. Experts recommend against using HGH to treat aging or age-related conditions.

How quickly does growth hormone work? ›

What To Expect With Growth Hormone Treatment. The main thing to expect is growth! Although it takes about 3 to 6 months to realize any height differences, the important thing is that your child will grow — probably 1 to 2 inches within the first 6 months of starting treatment.

What are the 4 kinds of growth hormone? ›

The secretion of the growth hormone is regulated by the hypothalamus and mediators of growth hormone actions. Other factors include- growth hormone-releasing hormone, somatostatin (SRIF), growth hormone-releasing peptide (ghrerin), and insulin-like growth factor (IGF-I).

What is the main growth hormone? ›

Human growth hormone, also known as hGH and somatotropin, is a natural hormone your pituitary gland makes and releases that acts on many parts of the body to promote growth in children. Once the growth plates in your bones (epiphyses) have fused, hGH no longer increases height, but your body still needs hGH.

How does growth hormone work? ›

GH stimulates the epiphyseal growth plates in the bone, which are responsible for bone elongation. GH also triggers the release of the insulin-like growth factor-I (IGF-I) protein, which stimulates the growth of bone, muscle and other tissues in response to GH and also, in turn, regulates GH release from the pituitary.

What are the dangers of growth hormone? ›

High levels of human growth hormone over a long period can produce irreversible acromegaly, but even smaller doses can lead to complications such as heart disease and diabetes. And because these hormones must be taken as injections, there are further administration risks such as a blood clot or dose error.

What is the problem with growth hormone? ›

Growth hormone deficiency (GHD), also known as dwarfism or pituitary dwarfism, is a condition caused by insufficient amounts of growth hormone in the body. Children with GHD have abnormally short stature with normal body proportions. GHD can be present at birth (congenital) or develop later (acquired).

Are growth hormones steroids? ›

No, HGH is a peptide hormone, not a steroid. A peptide is a substance from two or more amino acids. People often confuse human growth hormone (HGH) with other substances that can improve athletic ability, but HGH is not a steroid.

What are the types of secretagogue? ›

The insulin secretagogues can be divided into two main classes of glucose‐lowering drugs, namely sulphonylureas (e.g. glibenclamide/glyburide, glipizide and gliclazide) and meglitinide analogues (nateglinide and repaglinide).

Is metformin an insulin secretagogue? ›

Abstract. Metformin has been used successfully since the 1950s as first line pharmacotherapy to treat people with type 2 diabetes. It is a biguanide that decreases blood glucose concentration by mechanisms different from those of insulin secretagogues, such as sulphonylureas, or exogenous insulin therapy.

How does ibutamoren make you feel? ›

Worst of all, ibutamoren has not even been approved for human use, which means there is no toxicity data and the extent of potential side effects, particularly long-term ones, remain unknown. Reported side effects include increased appetite, swelling, anxiety, numbness and muscle pain.

Does MK-677 build muscle? ›

Helps Build Muscles

MK-677 stimulates Growth Hormone and IGF-1 which each factor in significantly to maintaining lean body mass. Growth Hormone is believed by many to stimulate an increase in muscle size and strength and the ability of MK-677 to increase Growth Hormone production make it a popular choice.

How long does it take for MK-677 to kick in? ›

MK-667 can help because it is famous for improving sleep. Once you take the product, it boosts Growth Hormone production, improving sleep quality. For the substance to work perfectly in improving your sleep, take it an hour before bed. You will notice some changes after two weeks.

Is MK-677 safe? ›

The use of MK-677 Ibutamoren is illegal and extremely dangerous. It does offer huge muscle gains and increased body fat burning, however, it is very likely to cause you serious side effects. Relevant scientific research and statistics show that its long-term use can lead to serious health problems: gynecomastia.

What are examples of secretagogues? ›

Secretagogues, such as sulfonylureas and glinides, increase insulin secretion from the pancreas. Secretagogues are medicines that stimulate the beta cell to secrete insulin. Secretagogues include the sulfonylureas and glinides.

What are growth hormones released by? ›

Abstract. Growth hormone (GH) is secreted by the anterior pituitary gland in a pulsatile fashion under the regulation of two hypothalamic peptides: GH-releasing hormone (GHRH) stimulates GH synthesis and secretion while somatostatin inhibits GH release.


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