Do Peptides Work For Weight Loss?

If you are trying to lose weight but are struggling to do so through diet and exercise alone, peptide therapy may be an option for you. Indeed, peptide therapy has demonstrated effectiveness in aiding weight management, along with offering other benefits. This article explains how peptides work, their side effects, and the various types of peptides available on the market.

What are peptides, and how do they work?

Peptides are short-chain amino acids connected with a peptide bond. They are shorter and smaller than proteins and are found in cells and tissues of the body. Peptides are used in many physiologic processes for the growth, development, and survival of cells. Aside from peptides in the body, peptides are also naturally found in food sources such as meat, fish, beans, lentils, and oats.

Peptides, being versatile molecules, exhibit diverse functions determined by their sequence, structure, and properties. Consequently, they operate through various mechanisms. Depending on their type, peptides serve as structural scaffolds for cells and tissues, interact with cellular receptors to either initiate or inhibit specific signaling pathways, and bind with other molecules to facilitate or inhibit their functions.

How can peptides help with weight loss?

Peptides can help reduce weight through several cellular mechanisms, which often primarily involve effects on appetite and metabolism as well as fat loss and muscle preservation.

Effects on the appetite and metabolism

Weight is largely influenced by appetite and metabolism. In fact, a naturally occurring peptide called glucagon-like peptide-1 (GLP-1) slows stomach emptying, which makes the stomach feel full longer resulting in a reduction of food intake. It also affects the metabolism by stimulating insulin release, regulating blood sugar levels, and increasing energy expenditure. This is how some successful peptide drugs work by mimicking the effects of GLP-1.

Fat loss and muscle preservation

Some peptides may support weight loss more directly through fat loss and muscle preservation. For example, some weight loss peptide drugs may enhance lipolysis (the process of fat burning) by promoting the breakdown and utilization of the stored fats for energy production, which can generally reduce body fat. Meanwhile, achieving fat loss without losing muscle is recommended because muscles help maintain the body’s metabolic rate, which influences long-term weight management. Other peptides may also work by stimulating growth hormones to build and maintain muscle mass and/or reduce muscle breakdown.

Clinical studies and research

There are several scientifically-supported methods to lose weight, and peptide therapy is one of them. Clinically, many studies support the use of specific peptides in promoting weight loss.

In 2021, a large-scale clinical trial from the New England Journal of Medicine with 1,921 adults with overweight or obesity indicated that once-weekly semaglutide peptide plus lifestyle intervention can lead to significant body weight reduction. In 2022, the research from Nature Medicine supported this claim based on a 2-year term study of semaglutide effects in adults with overweight or obesity.

Another clinical trial showed that treatment with the peptide Survodutide achieved up to 20% weight loss in up to 40% of people with overweight or obesity.

Recently, the Journal of American Medical Association released the clinical trial of the peptide tirzepatide, which showed that continuous treatment can maintain and improve weight loss.

Best peptides for weight loss

Currently, commercial peptides for weight loss are usually synthetic forms of naturally-occurring peptides mimicking their functions. These formulations usually contain different substances that stimulate the release of growth hormone and activate receptors in the body.

Melanotan II (MT-2)

Melanotan II is a synthetic peptide form of the hormone called α-melanocyte-stimulating hormone (α-MSH). It is initially known to stimulate melanogenesis (tanning) and sexual arousal.

Later on, it was also found to suppress appetite leading to an increased rate of fat burning — especially useful for overweight and obese individuals. Research shows that MT-2 induces long-term body weight reduction even without calorie restriction.

GHK-Cu (copper peptide)

GHK-Cu is a tripeptide naturally occurring in human plasma. It has a well-documented range of biological effects on health, including regenerative and protective actions on blood vessels, nerves, skin, and other tissues. Because it's a small molecule, it can be absorbed through the skin more easily compared to larger peptides.

Commercially, GHK-Cu peptides are actively promoted for skin repair, wound healing, and anti-aging effects. Research identified that this peptide could activate a number of genes and turn off some others, which may explain its wide range of molecular effects. In terms of weight loss, GHK-Cu has limited research and clinical findings.

Fragment 176-191 and AOD9604

Fragment 176-191 and AOD9604 are both man-made peptides made from parts of human growth hormone (HGH). Fragment 176-191 contains amino acids 176-191 of HGH, while AOD9604 contains amino acids 177-191. They're very similar, differing by just one amino acid, so they're sometimes used interchangeably.

Fragment 176-191 is the lipolytic fragment of HGH, which breaks down fat leading to body weight loss and stimulation of fat metabolism. In a 3-month clinical trial, this HGH fragment was shown to promote more significant body weight loss compared to placebo. However, a 2007 clinical trial did not show it to be effective.

Ipamorelin

Ipamorelin acts strongly on the ghrelin receptor, mimicking the hormone ghrelin. This helps speed up metabolism and control the release of growth hormone. When it triggers the release of growth hormone from the pituitary gland, it prompts the breakdown of fat and the release of energy in the body.

Ipamorelin is often injected alongside another peptide CJC 1295, working in tandem to increase weight loss and lean muscle mass. The effects are typically observed after a month of use, with maximal effects observed after 3–6 months of daily administration. In this regard, as women have generally higher fat percentages than men, women may consider ipamorelin + CJC 1295 combination therapy when choosing the best peptides for female fat loss.

Tesamorelin

Tesamorelin is a synthetic version of GHRH, a hormone that controls the release of growth hormone in the body. It's used to help increase muscle growth and decrease body fat. Importantly, tesamorelin tends to have fewer side effects than GHRH itself.

In HIV patients, tesamorelin is used to decrease belly fat associated with lipodystrophy, a metabolic condition causing increased body fat deposition in certain areas of the body. After 26 weeks, tesamorelin abdominal injections can cause an approximate 15% reduction in visceral fat. A clinical trial in non-HIV positive, obese patients, conducted by Massachusetts General Hospital and Harvard Medical School, also showed similar beneficial effects.

Oral peptide supplements vs. injections

Certain drugs or supplements with peptides for weight loss are available in injection and oral forms, and it’s best to consult a health professional and read about the types of peptides before deciding to start using them. The following table looks at the distinct characteristics and potential advantages of each administration method.

Type	Route of administration	Mechanism	Bioavailability	Effects on the body
Oral supplements	Taken with food	Gets absorbed through the intestines	Decreases after passing the stomach and liver	Slower
Injections	Subcutaneous or transdermal injections	Straight into the bloodstream or muscles	High; does not get filtered by the liver	Faster

Other health benefits peptides offer

Peptides have a wide range of health benefits depending on their identity. They can even be designed and engineered for specific targets and purposes. Some common health benefits of specific peptides include:

Anti-inflammatory properties

Inflammation plays a central role in many diseases. Because of this, scientists are actively studying peptides as potential natural or synthetic treatments with anti-inflammatory abilities. These peptides usually work by disrupting signaling pathways that involve the expression of cytokines, which are molecules that primarily trigger inflammation.

Strengthening the immune system

Immunomodulator peptides that strengthen the immune system usually mimic the surfaces or cellular proteins involved in cell signaling pathways and protein interactions. These are typically essential in mediating the cascade of immune responses crucial during infection or disease development. Bioactive immunomodulatory peptides can also be found naturally in certain vegetables and mushrooms.

Slowing down the aging process

GHK-Cu, Epitalon, and Matrixyl are among the anti-aging peptides you can find on the market. These peptides are believed to work in various ways, like helping repair skin, smoothing wrinkles, restoring skin flexibility, shielding against UV rays, and even activating telomerase, which is an enzyme that affects the length of telomeres — protective caps on our chromosomes linked to aging.

However, it is important to note that these benefits are not inherent to all peptides but restricted to specific peptides with the right sequence, structure, and properties.

Do peptides help with muscle gain?

Peptides also show promise as performance enhancers, which is very attractive for active people and athletes, especially since amino acids are building blocks for building strong muscles.

Some peptides can help with muscle growth by stimulating growth hormone release, enhancing recovery, improving endurance, or directly promoting muscle hypertrophy. By influencing these physiological processes, peptides may support desirable muscle gains and loss of body fat. However, certainly, muscles need all essential amino acids for optimal muscle growth. As such, complete sources of protein are needed to gain optimal growth.

Collagen peptides vs. protein powder

Collagen peptides and protein powder contain amino acids that maintain metabolism and physiologic functions in the body. However, these two are not to be used interchangeably for your health needs. Whether you need collagen peptides for weight loss or protein powder, the following table compares the two supplements:

Type	Source	Examples	Functions	Weight loss	Dairy-free
Collagen peptides	Bones, skin, and cartilage of animals and/or fish	Keratin, collagen	Support skin, hair, nails, joints, and bone health	Yes	Yes
Protein powder	Dairy or plant sources	Whey	Promote muscle gain and strength	Yes	No

Safety considerations of using peptides for weight loss

Side effects of peptides for weight loss are rare among healthy individuals, especially if the peptide is designed from or a derivative of a naturally occurring protein inside the human body. If it happens, some side effects may occur immediately after intake/injection and may include:

• Heartburn
• Feeling of fullness
• Bad taste in the mouth
• Rashes
• Itching
• Swelling
• Redness at the injection site

Always consult with a medical professional before starting any peptide therapy regimens for your bodybuilding or weight loss goals, especially if you have other conditions or if you’re taking other medications to avoid potential interactions. You should also consider your budget, as some peptides may take a longer time to make a significant change or may need continuous treatment to maintain your weight.

Ultimately, the fastest way to lose fat is to employ multiple strategies for weight management. With peptides, proper diet, exercise, and other health tips, weight reduction may even be achieved with a better response. To gain the best benefits from peptides, it is best to consult a health professional to evaluate your personal requirements. Learn more about myths and proper ways to lose weight and get informed about the types of peptide supplements before deciding to start using them.