< Blog < Lose Weight < Supplements & Remedies < Peptides for Weight Loss: Efficacy and Best Types (Science-Backed)

Peptides for Weight Loss: Efficacy and Best Types (Science-Backed)

7 min read
a woman is taking a supplement, smiling, peptides for weight loss
Melissa Mitri post Reviewer Melissa Mitri post Reviewer
Verified by Melissa Mitri
MS, Registered Dietitian, Former President of CT Academy of Nutrition & Dietetics

What are peptides, and how do they help in weight loss? What are some of the best peptides for weight loss? Let’s find out!

Table of Contents

If you’ve been trying to lose weight but haven’t succeeded yet, you may want to turn to a supplement or medication that promises quick weight loss. There is a long list of treatments that are being touted as weight-loss remedies — some of which are effective and some, not so much. 

For instance, vitamin B12 shots are thought to boost metabolism and promote weight loss; however, it turns out there is no scientific evidence to prove that claim. Laxatives are one more example of a medication that is commonly misused for weight loss.

Peptides for weight loss are another therapy that is being widely discussed. What are peptides, and do they really induce weight loss? What are some of the best peptides for weight loss? We aim to discuss these topics and a few more in this article.

What Are Peptides?

Peptides are short chains made up of amino acids (the units that proteins are made of as well). A peptide usually contains 2 to 50 amino acids linked by chemical bonds. Longer chains containing more than 50 amino acids are called polypeptides. 

Peptides are molecules that naturally occur in the body. Natural peptides can be derived from animal and plant sources as well. There are also synthetic peptides created or modified in a lab by stringing specific amino acids together.

Some of these peptides possess various therapeutic benefits, such as muscle repair, the ability to fight disease, and of course, weight loss. These therapeutic peptides can act as hormones, neurotransmitters, or growth factors [1]. Once inside the body, they can provide various health benefits. 

Peptides vs. Proteins: What’s the Difference?

Proteins can be made of one or more polypeptides, depending on their type. While the basic building block of proteins and peptides is the same, there are some core differences between these two types of molecules. 

The most noticeable difference is their size: peptides are much smaller than proteins. 

Another difference is their structure. While a peptide remains a simple chain, proteins are complex structures created through internal bonding in polypeptides.

Are Peptides Effective for Weight Loss?

While the research on peptide therapy for weight loss is still in its early stages, there is some scientific evidence that suggests the effectiveness of some peptides in weight loss [2]

Some of these peptides activate the production of certain hormones to induce fat loss [3], while others act by curbing the appetite and controlling the gut microbiota [4]

One novel peptide called Retatrutide works by mimicking the action of a hormone called GLP-1, which keeps the stomach full for extended periods [5].

Another group of peptides inhibits the generation and deposition of lipids in fat cells, thus controlling weight gain [6]. This reduces fat mass and the size of fat cells, which results in a drop in body weight. 

Are Peptides Fat-Burners?

In short, some are. Certain peptides, such as Hexarelin, trigger a fat-burning effect [7]. These fat-burning peptides do so by stimulating the release of human growth hormone (HGH) — a hormone that increases fat burning and controls fat buildup in fatty tissues [8]

You may also like: Digestive Enzymes For Weight Loss

Best Types Of Peptides For Weight Loss

There are many types of weight loss peptides on the market today. Here we list some of the best peptides for weight loss backed by science.


In a mouse study, this peptide was shown to slow down fat accumulation and increase lean muscle mass, thus supporting a healthy metabolism [9]. It also increased the physical performance of mice.


Tesamorelin is a peptide particularly effective for losing belly fat. It was found to reduce belly and liver fat within six months in a primary human trial [10]


This peptide has been reported to be effective in reducing diet-related obesity. In one mouse study, 5-Amino-1MQ suppressed lipid accumulation in fatty tissues, thus reversing obesity in mice [6].

Retatrutide (LY-3437943)

Retatrutide is a promising weight-loss peptide that is currently completing phase 2 trials [11]. It has been shown to reduce weight and improve blood glucose control in obese mice [5]

Oral Peptides vs. Peptide Injections: Which Form Is Best?

Peptides for weight loss generally come as either oral supplements (capsules or powders) or injections.

While both of these forms can be effective, there are some differences in their bioavailability (i.e., how efficiently our body utilizes them) and how they work.

Depending on your requirements, one form may be better than the other. You need to carefully consider the pros and cons before choosing the best method for you. 

The following table compares the differences between the two forms:

Oral supplementsInjections
Easy to self-administerCan be painful/intimidating to self-inject
Absorbed through the GI systemGets directly into the blood or muscles
Action is somewhat slowerActs faster once inside the body
Gets filtered through the liverDoes not get processed by the liver

Other Benefits of Peptides

Apart from weight loss, therapeutic peptides can impart several other benefits. 

They Can Be Used to Treat Diabetes

Research has identified several peptides with antidiabetic activity. They have been shown to reduce blood sugar levels, improve insulin sensitivity, and inhibit diabetes-inducing enzymes [12].

They Can Improve Skin Health

Certain antimicrobial peptides have been recognized for their ability to repair the skin barrier to offer protection against bacteria and viruses in the environment [13].

They Can Increase Muscle Mass

Collagen peptides are particularly known for their ability to increase lean muscle mass and improve body composition when combined with resistance training [14].

They Can Control Inflammation

Some peptides act as anti-inflammatory agents and can be thus used to help manage inflammatory diseases [15].

They Can Improve Heart Health

The MOTS-C peptide, which we discussed earlier, has been shown to improve heart muscle performance during exercise training [16].

They Can Prevent Bone Loss

Collagen peptides have also been found to increase bone mass, thus increasing bone density [17].

Peptide Side Effects

Most of these peptides are not likely to cause serious side effects as they mimic natural peptides. However, as with any supplement, some minor, undesirable effects can occur depending on the individual’s reaction to the active ingredients. They can include:

  • Skin rashes and itching
  • Swelling at the site of injection
  • Upset stomach
  • Nausea
  • Fatigue

These side effects will most probably be temporary. If, however, they don’t go away after a few days, it’s best to get them checked by a doctor.

Can You Lose Weight on Peptide Therapy Alone?

You most likely won’t be able to achieve significant weight loss relying only on peptides. Although peptide therapy for weight loss can sound like an easy fix for weight loss, it’s not. 

Much like other weight-loss supplements, these peptides can only do so much. While they can certainly boost your metabolism and fat-burning potential, you need to have a healthy weight-loss strategy in place to see sustainable results. 

A calorie deficit attained through a controlled diet and regular exercise is the key to progress when it comes to weight loss. You can also try an eating schedule like intermittent fasting to effectively lose weight. 

You may also like: Phentermine For Weight Loss


Peptide injections and supplements for weight loss can be an effective add-on to your healthy weight management plan. However, they are not a magic pill. Also, keep in mind that research on some weight-loss peptides is scarce, and most of it is based on animal studies. 

Be sure to do thorough research or consult a dietitian before choosing a weight-loss peptide supplement that suits your needs.

Disclaimer This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!

You may also like

We recommend reading