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  • Writer's pictureAmanda

Peptides for Bodybuilding: Do They Work, and Are They Safe?

Updated: Nov 17, 2023

Peptides are a popular performance-enhancing aid in the bodybuilding community. Growth hormone secretagogues (GHS) are a type of peptide that attracts particular interest. Bodybuilders are athletes that often seek to alter their body composition as quickly and efficiently as possible. This explains why many resort to supplements or other aids to reach their desired training and physique goals. People often view peptides as a more natural alternative to anabolic steroids and praise them for their ability to boost muscle mass, promote fat loss, and help bodybuilders get the most out of their workouts. This article reviews everything you need to know about peptides for bodybuilding, including their safety and whether they actually work. What are peptides? Peptides, including GHSs, are short chains of amino acids, which are little molecules that are the building blocks of peptides and proteins. Peptides exist naturally in your body, but you can also find them in animal or plant sources of protein, including meat, fish, dairy, eggs, beans, lentils, and whole grains. Manufacturers can isolate these peptides or make them by combining individual amino acids (2, 3). The structure of peptides is similar to that of certain hormones or messaging compounds already present in your body. Many also have the ability to penetrate tissues (4). These short chains of amino acids are involved in a variety of processes in your body, including in the production of hormones and DNA. They’re also helpful when building muscle tissue, which is what makes them particularly appealing to bodybuilders (1, 5, 6, 7, 8). What do peptides do in your body? Because peptides’ structure can be similar to those of some hormones and messaging compounds in the body, they can engage with and activate several receptors throughout the body, thereby influencing a variety of bodily processes (5). Depending on their sequence and composition, certain peptides may help prevent blood clots, boost the immune system, protect cells against damage, and reduce cholesterol, inflammation, and blood pressure (2). Specific peptides may also help boost the release of hormones known to stimulate muscle growth, body fat loss, and exercise performance and recovery. This makes them particularly appealing to bodybuilders interested in maximizing their training results (1, 6).

How do they work for bodybuilding? Bodybuilders are typically interested in changing their body composition as quickly and efficiently as possible. Research suggests that certain peptides may help them achieve these goals. Growth hormone secretagogues (GHS) are a group of peptides that attract particular interest among bodybuilders because they can stimulate the production and release of human growth hormone (HGH). HGH is a hormone that the pituitary gland secretes. It can help enhance muscle growth and promote the loss of body fat (7). It does so, in part, by stimulating the liver to release insulin-like growth factor-1 (IGF-1). In turn, IGF-1 triggers muscle protein production and muscle growth. It also appears to indirectly promote the breakdown of body fat (7, 8). Back in the 1980s, HGH was a widely popular performance-enhancing drug among various recreational and professional athletes, including bodybuilders (6, 7). However, due to safety concerns, regulating bodies like the International Olympic Committee banned the off-label use of HGH from 1989 onward (7). People believe GHSs offer many of the same benefits as HGH with fewer side effects. This may explain their popularity as an alternative to HGH among bodybuilders (9, 10).

To date, research suggests that GHS increases the release of HGH or IGF-1 in humans. However, few studies have investigated whether taking GHS actually leads to significant changes in body composition, exercise performance, or recovery (10). What’s more, no studies have examined the effect of GHSs on well-trained individuals. Therefore, more research is needed to determine whether GHSs provide any tangible benefits to bodybuilders. For this reason, scientists currently do not know which muscle groups peptides may affect most, or which workouts they might be best suited for (11). Peptide types for bodybuilding Bodybuilders may be particularly interested in peptides known as growth hormone secretagogues (GHS). The most popular GHSs people use for bodybuilding include:

  • Growth-hormone releasing hormones: such as sermorelin, tesamorelin, CJC-1293, and CJC-1295

  • Ghrelin and compounds mimicking its actions: such as lenomorelin, anamorelin, ipamorelin, macimorelin, and tabimorelin

  • Growth hormone-releasing peptides (GHRPs): such as alexamorelin, GHRP-1, GHRP-2, GHRP-3, GHRP-4, GHRP-5, GHRP-6, and hexarelin

Each of these peptides ends up stimulating the production and release of HGH, although they may do so in slightly different ways (9, 10). Manufacturers often promote each category for slightly different purposes. However, it’s important to note that no studies to date have investigated the effects of GHSs in bodybuilders or other well-trained individuals. Therefore, indications and recommended dosages are typically based on anecdotal evidence rather than science. Safety Based on the current literature, the safety of using GHSs over the short and long term is unknown. Studies investigating their safety have been small and short in duration. Therefore, scientists need to do much more research investigating the safety of GHS (10, 11). Common side effects of using GHS may include an increased appetite, elevated blood sugar levels, and fluid retention. GHSs may also decrease the body’s sensitivity to the hormone insulin, making it more difficult to maintain normal blood sugar levels (10T). There may also be a risk of contamination if people use non-sterile needles to inject GHS. To date, the Food and Drug Administration (FDA) has only approved a handful of types of GHS to treat specific medical conditions by prescription only. GHSs are also currently on the World Anti-Doping Agency’s list of prohibited substances (7, 11). Doing so may be risky, as their long term safety is unclear, and it’s virtually impossible to evaluate the quality of the purchased supplement. For these reasons, any off-label or nonprescription use of GHSs is not safe.


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