Peptides for Weight and Muscle: Prescription Drugs, Unapproved Substances and the Limits of Evidence

Peptides come up online in connection with weight loss and muscle gain, but prescription drugs such as semaglutide are not the same as substances that have lost approval or never had it. This article explains what peptides are, which are approved medicines and what the safety concerns are, as general information. Evidence is limited; ask a healthcare professional before considering any peptide.

Peptide therapy is often described online as a natural alternative to anabolic steroids for raising human growth hormone (HGH), but this comparison is not supported by solid evidence. The boost in hormone production that peptides offer might lead to faster recovery and increased muscle mass. For weight loss, peptides could control appetite and signal to the body to burn fat for energy instead of carbs.

Peptide therapy is being studied by people interested in body fat, lean muscle mass and exercise recovery; evidence is mixed and mostly limited.

What are Peptides?

Peptides are chains of amino acids. These chains are considered the building blocks of proteins. They are involved in many different processes throughout the body. Peptides have also been shown to have a positive effect on stress, anxiety, and depression.

There are two types of peptides: the ones your body makes itself (endogenous) and the ones you get from outside sources (exogenous). The ones your body makes act like messengers between cells, carrying signals for functions like pain, hormones, and digestion.

The external peptides that come from supplements, food, and medication, might help with increasing growth hormones, controlling appetite, and determining how your body uses energy.

How Peptides Work for Weight Loss?

Researchers have noticed changes in body weight in some people using peptide-based medications, although this was not their original purpose. Specifically, glucagon-like peptide-1 (GLP-1) and its receptor agonists stimulate insulin production and have been studied for blood sugar; they have also been reported to reduce appetite and promote a feeling of fullness.

With the feeling of satiety that these peptides might provide, people are more able to focus on a balanced diet, decreasing body weight and fat burning. Of course, these peptides are not the only thing that contributes to your weight loss journey. Factors such as fitness regimes, body composition, and personal health history.

What are Amino Acids?

Amino acids are small molecules that make up the basic building blocks of proteins. All living things use amino acids to make proteins. Each protein has its chain of amino acids, which take different shapes and perform different functions in the body.

There are over 500 naturally occurring amino acids, but only 20 of them are used by your body to build proteins. These 20 essential amino acids have slightly different chains, giving each protein its unique properties. Basically, when you combine these amino acids in different ways, you get different proteins.

What Peptides are Best to Lose Weight?

The best peptides for weight loss can vary depending on each person. A medical provider can help you determine which one is right for you. But here are some of the best peptides to facilitate weight loss:

Semaglutide

Semaglutide mimics a natural hormone called GLP-1, which helps regulate blood sugar and potentially weight. GLP-1 receptor agonist that has recently become very popular under the names Ozempic (created to treat Type 2 diabetes) or Wegovy (for obesity). This medication is a once-a-week injection that has been approved by the FDA.

Liraglutide

Liraglutide is known commonly under the brand names Saxenda or Victoza. Here’s how this peptide works:

Tirzepatide

Tirzepatide, known by the brand names Mounjaro and Zepbound, is a relatively new medication approved by the FDA in 2022 for the treatment of type 2 diabetes. It has also gained attention in studies of weight, including in people without diabetes, and it is a prescription medicine used under a doctor's supervision.

Tirzepatide has been studied for weight loss, which appears to be mainly through reduced appetite, delayed gastric emptying and enhanced feeling of fullness.

Peptides for Muscle Growth and Performance

Peptides are also discussed in connection with muscle building and lean muscle mass, but most of these substances are not approved for that purpose. Several peptides are discussed online for muscle growth, often described as mimicking certain growth hormone releases; evidence is limited.

Here are some of the most well-known peptides for muscle growth and recovery. Unfortunately, the FDA recently updated its regulations concerning specific peptides, so it's important to consult with a medical provider regarding peptide therapy.

Ipamorelin

Ipamorelin is described as acting on the hypothalamus to raise growth hormone levels. It was studied for body composition earlier, but evidence is limited and it is no longer approved. Unfortunately, this peptide is no longer approved by the FDA because they cite a study in which serious adverse events, including death, occurred when individuals used Ipamorelin intravenously.

Cjc-1295

CJC-1295 is a synthetic peptide known for increasing protein synthesis and muscle tissue growth, improving recovery and repair from injuries, and helping people lose weight alongside muscle growth. However, like Ipamorelin, CJC-1295 is no longer approved by the FDA due to its risk for increased heart rate and cardiac events.

GHRP-6

GHRP-6 (Growth Hormone Releasing Peptide-6) is another synthetic peptide hormone that stimulates the release of growth hormone. It is one of several synthetic peptides developed for its growth hormone-releasing activity. But just like Ipamorelin and CJC-1295, GHRP-6 is no longer approved by the FDA because of its possible effect on cortisol and increase in blood glucose due to decreases in insulin sensitivity.

Hexarelin

Hexarelin is known for being one of the most potent growth hormone-releasing peptides. It is described as acting on the pituitary gland to raise GH production.

Safety Considerations and Potential Risks

Peptide therapy for weight loss and muscle growth has become popular online, especially among bodybuilders, but many of these products are unapproved. However, there are some things to consider regarding the health and safety of using peptide therapy.

Depending on the peptide, common side effects might include:

• Retaining fluid and bloating.

• Fatigue, dizziness, and headaches.

Claims Made About Peptides

However, peptides might have other potential benefits that improve overall health. Certain peptides can:

• Immune system claims
• Inflammation claims
• Bone density claims
• Cell protection claims
• Cholesterol claims
• Blood pressure claims

Some peptides might give your body a boost to produce more human growth hormone (HGH). This can translate to building more muscle, recovering quicker after workouts, and even keeping your appetite in check, all leading to a more sculpted physique weight loss goals.