Whether competing on a world stage like the Olympics or in front of one's hometown in a high school stadium, succeeding at any sport or in any arena usually requires getting a leg up on the competition. To do this, some athletes train harder, some train longer, and some have even resorted to cheating by taking synthetic hormones such as anabolic steroids. 

But for decades, many top athletes have turned to enhancements so natural, their own bodies produce them. Among such enhancements that have been incorporated into many healthy diets, are peptides. So what are they? Read on to learn everything you need to know.

What are peptides? 

Peptides are amino acids − the body's building blocks of protein.

Josh Redd, NMD, the founder of RedRiver Health and Wellness and author of "The Truth About Low Thyroid," says peptides "function like conductors for a biological orchestra" by binding to one's cellular receptors, helping hormone regulation, improving immune response and by triggering neurotransmitters. "This is why, in addition to athletic enhancement, peptides have become popular in the research world for treating things like aging, obesity, cancer and diabetes," he says. 

What's more, there are many different peptides, "and each serves its own function to help the body," says Jesse Bracamonte, MD, DO, a family medicine physician at Mayo Clinic in Arizona.

What does taking peptides do for you?

Different peptides such as creatine peptides, collagen peptides, copper peptides and antimicrobial peptides each have various health benefits. Creatine peptides promote the release of hormones that influence one's exercise performance, muscle recovery and body composition, which is why some athletes are drawn to the amino acids.

Other peptides affect one's endocrine system, which plays an important role in cell and organ growth and development, per the National Institutes of Health National Cancer Institute (NCI). Copper peptides act as antioxidants, which the NCI notes counteract harmful free radicals caused by environmental factors like UV rays, pollution and cigarette smoke. 

Mary Stevenson, MD, associate professor of dermatology at NYU Langone Health, says collagen peptides repair skin cells, "which can help reduce and prevent fine lines and wrinkles," and that they also promote healthy nails and hair. 

And antimicrobial peptides are essential for a healthy immune system.

What foods have peptides?

Though one's body produces peptides naturally, peptides are also found in many food and supplement sources. "All the food we eat is broken down by the body into amino acids," explains Stevenson. 

Redd says animal products including meat, milk and eggs "are the best sources" of peptides. Beyond animal sources, plant-based sources such as legumes, flax seeds, hemp seeds, soybeans, oats and wheat are also "enriched in active peptides," says Bracamonte.

Many powder and capsule supplements, including collagen supplements, have active peptides as well. Peptides can also be found in beauty products and topical applications such as creams, lotions, face masks and serums. 

Are eggs good for you?Egg yolks vs. egg whites and what you need to know.