Peptides: Types, Uses, and Benefits

Medically Reviewed by Zilpah Sheikh, MD on February 15, 2024
9 min read

Peptides are strings of molecules called amino acids, which are the "building blocks" of proteins. Peptides are basically short proteins that are about 2-100 amino acids long.

Your body makes peptides that serve important functions in some of your body's most necessary processes. For instance, insulin is a 51-amino-acid-long peptide hormone that helps your cells take in sugars from your food to use for metabolism and store them in your liver.

Researchers have been working to develop peptides as treatments for some medical conditions since 1921. In fact, insulin was the first peptide ever made in a lab by scientists (called a synthetic peptide), and it's been used to treat people with type 1 diabetes since 1923.

Peptide drugs may have some advantages over other drugs because they may:

  • Be easier to send where they need to go in your body
  • Have fewer side effects
  • Be safer because when your body breaks them down, their byproducts are amino acids that your body can recycle

Studies show that some peptides may also have benefits for your skin, muscles, and maybe your weight. So, for decades, companies have been putting them into skin care products and dietary supplements you can buy over the counter.

Both peptides and proteins are made up of strings of amino acids that are held together by peptide bonds. The main difference is that peptides are shorter strings of amino acids than proteins, although the terms aren't used precisely. Most scientists refer to chains with over 100 amino acids as proteins.

Also, scientists call peptides that are about 10-20 amino acids long oligopeptides and peptides bigger than 20 amino acids long polypeptides.

Your body makes lots of different peptides, each of which has a different role. Scientists can also make synthetic peptides in the lab. Companies have been adding peptides to skin care products for decades. Certain peptides may offer the following benefits:

Peptides for anti-aging

The protein collagen is one of the main building blocks of your skin, muscles, bones, tendons, ligaments, and other connective tissues. Collagen provides all these parts structure, strength, and the ability to stretch. As you get older, your body makes less collagen and breaks down the collagen you have faster. This causes your skin to wrinkle and sag and your muscles, bones, and tendons to shrink, stiffen, and get weaker.

Collagen injections can plump your skin and help fill in lines and wrinkles. But research also shows that collagen supplements you take by mouth may help your skin stay moist and elastic, especially if you're older than 30. They may also help ease pain and improve joint function in people with osteoarthritis (the "wear-and-tear" kind of arthritis that's usually due to aging).

Your body can't absorb collagen in its whole form, so it's usually broken down into smaller collagen peptides (also called hydrolyzed collagen) of about three to four amino acids to use in supplements. You can find these oral supplements as pills or powders in health food stores, drug stores, and some grocery stores.

Copper (GHK-Cu) peptide is another peptide that may improve your body's ability to make collagen and elastin, which is a protein in your skin. It also acts as an antioxidant and helps repair skin damage. Research shows that GHK-Cu in face and eye creams may reduce lines, wrinkles, and age spots (hyperpigmentation), and improve skin moisture, elasticity, and thickness. It may also help your hair grow thicker. You can find copper peptide in skin care products (such as lotions, creams, and serums) and hair serums at department stores, beauty supply stores, spas, and online. Earlier, copper peptide injections used to be available at wellness centers and spas, but the FDA banned these in September 2023 because they saw impurities in the liquid version, which triggered immune system reactions in some people.

A synthetic peptide called palmitoyl pentapeptide-4 (Matrixyl) may also help your body make more collagen, improving your skin's texture and clearing up age spots and dark eye circles. You can find face creams and serums with Matrixyl at the same places where you buy copper peptides.

Peptides for skin

Your body makes a few peptides in your skin, includingantimicrobial peptides (AMPs) that help you fight bacteria, heal wounds, and build a strong skin barrier. If your skin makes too few or too many AMPs, you may have psoriasis, eczema, rosacea, or acne. Lotions and serums that include AMPs may help restore the skin barrier and ease swelling and redness in people with psoriasis or eczema. Also, AMPs may help keep bacteria from infecting your pores and causing acne, and may also help people with diabetes who have ulcers or sores heal better. You usually need a prescription for medicines containing these peptides, so talk to your doctor if you are interested in trying one of these.

Peptides for muscle growth and weight loss

Creatine and collagen supplements may help boost muscle growth or muscle repair. However, certain types of synthetic peptides thought to be linked to muscle growth, known as growth hormone secretagogues (GHS), may be illegal and unsafe. For instance, they may reduce your body's sensitivity to insulin and increase your blood sugar. In addition, if you are competing in an athletic competition, all GHS supplements are on the World Anti-Doping Agency's banned list.

Peptides for hair growth

Some peptides may help you grow longer, thicker, and healthier hair. For instance, collagen peptides such as GHK-Cu may help trigger more hair growth in people with pattern hair loss. You can buy this as a serum that you can apply to your scalp. Other options include collagen peptide supplements in the form of powders or pills and folitin, which is another serum you can apply directly to your scalp.

Peptides for bone loss

Collagen peptide supplements may also help improve your bone mineral density. In one study, taking collagen peptide supplements daily for a year increased bone mineral density in the upper back and upper leg bones of people assigned female at birth (AFAB) after menopause. There are also a couple of peptide drugs that are FDA-approved to treat osteoporosis.

Peptides for testosterone

Some peptides may help increase testosterone levels by triggering your body to make and release gonadotropin-releasing hormone (GnRH), gonadotropin luteinizing hormone (LH), and follicle-stimulating hormone (FSH). These three hormones are the main ways your body makes testosterone. Two such peptides are kisspeptin-10 and gonadorelin. In one study, kisspeptin-10 increased the average serum testosterone levels within 24 hours of injection. In another study, gonadorelin increased testosterone levels and restored fertility in people assigned male at birth (AMAB) who had low testosterone levels because they didn't make enough GnRH.

Peptide therapy is the use of peptides to change or improve how certain parts of your body work. For instance, some athletes use growth hormone-releasing peptides to help their body produce more growth hormone. This can help their bones and muscles recover after hard training and competing.

Depending on the peptide, they are used in several different ways, such as:

  • By mouth (oral or dietary supplements)
  • By smoothing on your skin (topical) or in a patch (transdermal)
  • By squirting them in your nose (nasal)
  • By injection at your doctor's office or a wellness center (peptide injection)

The form in which peptides are used depends on a lot of different factors. For instance, most peptides aren't very stable, so they just break down when they're put in a supplement or cream. Also, peptides in oral supplements are digested just like your food, so they don't enter your bloodstream intact. Peptide injections are common because it's easier for your body to use the peptides when they are injected directly into your blood.

You can buy peptides as dietary supplements, including pills or protein shakes. Manufacturers claim they can, for instance, help you build muscle, recover after a workout, or boost weight and fat loss.

But there's little direct evidence to back up most of these statements. And it's not clear how well your body can absorb whole peptides from supplements, as they are usually completely broken down into amino acids in your digestive system.

Some of the peptides you can buy in supplements include:

  • Creatine peptide, said to help you build muscle
  • Collagen peptide, said to prevent aging and improve the health of your skin, hair, and nails
  • Follistatin, said to help you gain muscle and lose weight

Peptides are naturally found in many foods, especially foods that are good sources of amino acids, such as:

  • Meat
  • Fish and shellfish
  • Beans and lentils
  • Soy
  • Oats
  • Flaxseed
  • Hemp seeds
  • Wheat

Peptides are also used to create drugs to treat a wide variety of disorders and conditions. More than 100 peptide drugs are currently FDA-approved in the U.S. Examples of these drugs include:

  • Abarelix (Plenaxis) and Degarelix (Firmagon) for advanced prostate cancer
  • Carfilzomib (Kyprolis) for multiple myeloma
  • Enfuvirtide (Fuzeon) for HIV
  • Exenatide (Byetta), Liraglutide (Victoza), Lixisenatide (Adlyxin), Albiglutide (Tanzeum), Dulaglutide (Trulicity), and Semaglutide (Wegovy, Ozempic) for type 2 diabetes
  • Linaclotide (Linzess) for irritable bowel syndrome (IBS) with constipation and chronic idiopathic constipation
  • Teduglutide (Gattex) for malabsorption (when you don't absorb nutrients from your stomach and intestines very well)
  • Teriparatide (Forteo) and Abaloparatide (Tymlos) for osteoporosis
  • Ziconotide (Prialt) for severe chronic pain

Unlike some cosmetics and supplements, these drugs have been well-researched and are tightly regulated by the FDA. Ask your doctor if you have any questions about taking a peptide drug.

Peptide therapy is generally safe when you take it under the direction of your doctor.

For most healthy people, peptide supplements aren't likely to cause serious side effects. However, supplements aren't tested by the FDA before they're sold, so use caution when you buy and use peptide supplements. You should be especially cautious about taking supplements if you:

  • Are pregnant or nursing
  • Have a medical condition
  • Are taking medicines

Talk to your doctor about taking peptide supplements before you start taking them.

Some possible side effects of peptide supplements include:

  • Allergic reactions, such as hives, swelling, or difficulty breathing
  • Heart problems, such as high blood pressure, fast heart rate, and palpitations (fluttering or pounding heartbeat)
  • Stomach problems, such as nausea, vomiting, and diarrhea
  • Cognitive problems, such as headaches, dizziness, and fatigue
  • Skin sensitivity and rash (in case of peptides you apply to your skin)



Before you try or buy any dietary supplements:

  • Research the company’s website.
  • Look up the active ingredients in the supplement.
  • Be skeptical of claims that sound too good to be true.
  • Don’t take more than the suggested amount.

Tell your doctor about any supplements you take and why. If you’re having problems with your skin or hair, see a dermatologist for a diagnosis and a treatment plan. If you have an allergic reaction to a peptide-based skin care product, get medical attention as soon as possible.

Peptides are short protein chains of about 2-100 amino acids. Your body makes peptides that serve important functions in some of your body's most necessary processes, including how you digest and use energy from the food you eat, how hungry you feel, how your hormones work, and cell movement. Peptides have been used in medicines for about 100 years, and some peptides are made into oral supplements and skin and hair care products for anti-aging, muscle growth, and fat loss benefits.

Are peptides steroids?

No, peptides and steroids are different molecules. Peptides are chains of amino acids, while steroids are ring-shaped fatty molecules. Both can help you build muscle and burn body fat, but they do it through different processes. And while peptides don't seem to have many side effects, steroids can have many serious and sometimes permanent side effects. Steroids are controlled substances that are regulated by government agencies, but peptides tend to be widely available. Nevertheless, the World Anti-Doping Agency has banned the use of most peptides and all steroids in athletes who are competing.

What are the side effects of peptides?

Peptides are involved in many different processes in your body, so potential side effects depend on the peptide you are taking and how you're taking it. Some peptides haven't been thoroughly tested, but they're considered generally safe.