Peptides have emerged as a significant area of interest in the field of weight management. These short chains of amino acids, which act as messengers in the body, influence a variety of bodily functions, ranging from hormone regulation to cellular repair. As the landscape of medical weight loss evolves, peptides offer a biologically harmonious approach alongside traditional pharmaceuticals.
Understanding Peptides
Peptides are essentially small chains of molecules called amino acids, which are the building blocks of proteins. They occur naturally in the body and can also be synthesized in a lab to resemble the ones in your body. These therapeutic peptides play essential roles in metabolism, wound repair, inflammation control, and numerous other biochemical processes. Weight loss peptides fulfill their purpose by mimicking the hormones responsible for regulating your appetite and metabolizing fat.
How Peptides Work for Weight Loss
Peptides influence processes such as appetite regulation, energy balance, and fat breakdown, helping the body manage weight more efficiently. Peptides for fat loss work by signaling hormones and receptors that help the body burn fat while preserving muscle.
Peptides are powerful tools that regulate essential biological processes to support weight loss effectively:
- Boosting Fat Breakdown: Peptides signal the body to increase fat oxidation, making it easier to break down and use stored fat for energy.
- Supporting Muscle Retention: Unlike crash diets that often lead to muscle loss, peptides help maintain lean muscle mass, which is essential for a healthy metabolism.
- Curbing Hunger and Cravings: Some peptides influence hunger hormones, making it easier to manage appetite and avoid overeating.
- Enhancing Energy and Recovery: By improving sleep quality and supporting faster recovery, peptides help you stay active and maintain a balanced lifestyle.
Rather than being a quick fix, peptides work in harmony with your body's natural processes to create sustainable weight loss results.
Read also: Risks of Peptide Weight Loss Programs
Types of Peptides for Weight Loss
Several peptide drugs are marketed for weight loss. Your doctor can help you find the one that works best for you and your health. Some peptides help promote weight loss by helping to regulate blood sugar levels, metabolism, and appetite. Some of the most common peptides for weight loss belong to a class of drugs called glucagon-like peptide 1 (GLP-1) receptor agonists. These medications mimic the action of the natural hormone GLP-1, which the gut releases after eating.
Here are some key examples:
GLP-1 Receptor Agonists
Semaglutide and tirzepatide are examples of GLP-1 RAs, a category of peptides originally developed for diabetes management but found to promote weight loss through their actions on the pancreas and digestion. The “GLP-1” part of the name refers to a naturally occurring hormone in the gut that participates in a broad array of physiological functions. GLP-1 receptor agonists reduce appetite, improve blood sugar control, and enhance metabolic health.
- Semaglutide: This GLP-1 receptor agonist is labeled to treat type 2 diabetes (brand name Ozempic) or obesity (brand name Wegovy). It’s approved by the Food and Drug Administration (FDA) and typically given via a once-weekly injection. As a 2024 review explains, semaglutide is a GLP-1 receptor agonist. There are three separate semaglutide brands: Rybelsus, Ozempic, and Wegovy. Of these, the only drug to receive FDA approval as a weight loss aid is Wegovy. Semaglutide may not have the double-duty action of tirzepatide, but it’s still a highly effective treatment for achieving rapid weight loss. As a GLP-1 receptor agonist, it targets receptors in your body, including in your pancreas, that are responsible for regulating how full you feel after a meal, and it slows the rate at which food leaves your stomach.24 The result is that you’re likely to eat less than you normally would, so you avoid the excess calories that your body would otherwise store as fat.
- Liraglutide: Liraglutide (brand name Saxenda) is another GLP-1 receptor agonist that is specifically approved for weight loss. Researchers explain that it reduces appetite and helps people keep weight off for at least a year. This medication is typically given in a once-daily injection. As a 2024 review explains, the FDA approved liraglutide in 2014 for the treatment of adult obesity, and studies have also shown the drug to be effective in children ages 12 to 18 years. The review found that the number of individuals achieving a weight loss of 5% or 10% was significantly higher in the liraglutide group compared to the placebo group.
- Tirzepatide: Tirzepatide (brand name Mounjaro) is also a GLP-1 receptor agonist used to treat type 2 diabetes. This drug is approved by the FDA to treat diabetes and can be used off-label to treat obesity. It’s typically given via a once-weekly injection. In 2023, the FDA approved a tirzepatide injection with the brand name Zepbound for weight loss in adults with obesity or overweight and at least one weight-related condition. Tirzepatide activates GLP-1 receptors and glucose-dependent insulinotropic polypeptide (GIP), an intestinal hormone that plays a role in insulin secretion and lipid metabolism. Zepbound is both a GLP-1 receptor agonist and a GIP receptor agonist, so it helps reduce appetite and food intake. It is a subcutaneous injection that a person administers once a week. The recommended starting dose is 2.5 mg. After the first 4 weeks, a person can gradually increase the dosage in 2.5 mg increments over the course of 4 to 20 weeks until they reach their target weekly dosage of 5 mg, 10 mg, or 15 mg.
Growth Hormone Secretagogues
A growth hormone secretagogue, such as tesamorelin, is a compound that causes the body to increase its growth hormone levels. Besides affecting almost every tissue and organ, growth hormone promotes physical growth and normal metabolism.15 16 Its metabolic effects relate to its ability to stimulate the production of yet another hormone, insulin-like growth factor-1 (IGF-1).
- Tesamorelin: Tesamorelin is an off-label prescription for weight loss. Its FDA-approved use is for treating HIV-associated lipodystrophy, or excess abdominal fat accumulation resulting from antiretroviral therapy, and it has fared well in its specialty. This fat-reducing quality is what makes tesamorelin an attractive non-GLP-1 peptide option. It may be especially appealing to people who prefer a more moderate approach to body recomposition so as to avoid the sunken facial features.
Peptides Versus Ozempic
As Ozempic becomes a household name in medical weight loss, natural peptide therapies such as BPC-157 and MOTS-c are emerging as promising alternatives.
Read also: Weight Loss with Semaglutide
- Speed of Results: Ozempic typically produces faster weight loss results, especially in the first 3-6 months.
- Side Effects: Ozempic is associated with gastrointestinal symptoms, while peptides tend to have minimal side effects.
- Cost and Coverage: Ozempic is often covered by insurance but can be costly without coverage.
- Holistic Approach: Peptide therapy works best when prescribed by a qualified physician and integrated into a broader wellness plan.
BPC-157
Primarily known for its role in tissue repair and reducing inflammation, BPC-157 can also support gut health, improve insulin sensitivity, and help regulate appetite signals.
MOTS-c
MOTS-c is a mitochondrial-derived peptide that helps regulate fat metabolism, energy production, and glucose usage.
Administration of Peptides
Peptides used in weight management are typically administered via subcutaneous injection and prescribed under medical supervision.
Therapeutic peptides are usually administered by subcutaneous injection (a needle), to ensure the maximum amount of medicine enters your bloodstream to take effect. But oral alternatives - dissolving tablets, drops, troches - are available from some of the leading telemed providers. The answer comes down to bioavailability, or the amount of medicine your body actually absorbs.
GLP-1 medications are typically taken as a once-weekly injection. You use a small needle to inject the medication into fatty tissue - usually in your belly, thighs, arms, or upper buttocks.
Read also: Comprehensive Guide to Peptide Dosage
Efficacy of Peptides for Weight Loss
Weight loss varies by person and dosage of peptides. In a clinical trial of Ozempic (semaglutide), participants lost 8.3% of their body weight in a year compared to just 2.2% in the control group. If a person weighs 300 lb, for example, 8.3% of their body weight figures to a loss of 25 lb.
Other reports found the following:
- People who took Wegovy lost an average of 14.9% of their body weight compared to 2.4% in the placebo group over a 68-week period.
- People who took liraglutide lost around 8% of their body weight compared to 2.6% in the control group over a 56-week period.
- People who took tirzepatide experienced up to a 15% loss of body weight at the end of a 72-week study period.
Combining peptides with exercise is even more effective. In one study on liraglutide, participants who took the drug and exercised 150 minutes a week (moderate intensity) or 75 minutes a week (vigorous intensity) reduced their weight and body fat twice as much as participants who took the drug alone.
Potential Side Effects
Peptide therapy is generally well tolerated by 95% of patients, but like any treatment, it can come with some side effects. Overall, peptides do not cause serious side effects. The most common side effects with GLP-1 receptor agonists are gastrointestinal issues (nausea, constipation, and diarrhea). These effects may range from mild to moderate and mainly show up when increasing dosages. Severe side effects are possible but rare. Among our recommendations, the most serious one is the elevated cancer risk associated with growth hormone secretagogues like tesamorelin. The risk stems from the ability of growth hormone secretagogues to stimulate cell death and replication, two biological events that precede cancer development.
Tesamorelin can cause flu-like symptoms such as fatigue, nausea, and headache. Joint and muscle pain, of varying intensities, may also occur. These effects are usually mild and more typical at the start of treatment.
Potential side effects may include:
- Mild nausea or upset stomach
- Temporary irritation at the injection site
- Fatigue or headaches
- Changes in appetite
Researchers explain that weight loss in people who experience GI issues is slightly greater than in those who do not experience this side effect.
Precautions
Before prescribing peptides for weight loss, doctors must consider certain precautions. Peptides for weight loss may delay gastric emptying, which can reduce the effectiveness of oral medications.
The FDA cautions that both Wegovy and Zepbound may not be suitable for use during pregnancy, as these medications may harm the fetus. The FDA recommends that males and females of reproductive age discontinue using Wegovy at least 2 months before a planned pregnancy, as the drug can remain in the system for several weeks.
With Zepbound, the FDA recommends that females using oral contraceptives switch to a non-oral contraceptive method or add barrier contraception for 4 weeks after the initial Zepbound dose, and for 4 weeks after each dose increase.
Peptides for weight loss may also not be suitable for people with a personal or family history of certain conditions, including:
- Medullary thyroid cancer
- Multiple endocrine neoplasia type 2
- Hypersensitivity to the active ingredient, or any other ingredient in the medication
A person should contact a doctor if they want to discuss issues with their weight or require advice on appropriate weight loss methods and treatments.
Who is a Good Candidate for Peptide Therapy?
Peptide therapy is highly customizable, making it suitable for many individuals. Whether you’re dealing with post-pregnancy weight gain, age-related metabolism changes, or simply looking for an effective way to manage your weight, peptides could be an excellent option.
You may be a good candidate for peptide injections if you have:
- A BMI of 30 or higher
- A BMI of 27 or higher with a weight-related health condition like high blood pressure, high cholesterol, or diabetes
Who Should Avoid Peptide Therapy?
Peptides for weight loss are not suitable for everyone. You should not take peptides if you:
- Are pregnant
- Have a history or family history of thyroid cancer
- Have a history of multiple endocrine neoplasia (MEN) syndrome
Medical vs. Research Grade Peptides
Many of the therapeutic peptides you can find online are research-grade peptides, designed to be applied in laboratory settings but not to be consumed by humans. It’s crucial, then, that you use medical-grade products for your weight loss goals. You can get a prescription through your physician or one of the reputable telemed platforms.
Lifestyle Integration
GLP-1s can help you lose weight, but they aren’t a magic fix. All the clinical trials that showed these medications working also included education on eating and exercise. There is a potential to regain the lost weight, but those chances decrease when you work with a healthcare provider to transition off the medication safely.