There's no shortage of skin care ingredients to know and try. Depending on your needs, you may be met with a range of derm-touted suggestions from vitamin C (brightening), retinol (cell turnover), alpha-hydroxy acids (blemish control), and oh-so-many more. Peptides also fall under the expert-approved category yet don't always get the spotlight they so rightfully deserve. 

Peptides are chains of amino acids linked together by peptide bonds, and amino acids are the building blocks of proteins. Proteins like collagen, elastin, and keratin exist in our skin, hair, and nails—and thus caring for them should be a top priority for a well-rounded beauty routine. Peptides are naturally present in the body, and there are many kinds that all have their own unique properties and functions. 

When used topically, they act as messengers for the skin, says board-certified dermatologist Hadley King, M.D.: "Neuropeptides act as chemical messengers. In the skin they can be synthesized by keratinocytes or endothelial cells [which will, in turn, strengthen the epidermis, or skin barrier], or they can be released into the skin from nerve endings. They can act by modulating the release of neurotransmitters," she says.

Put simply, "When you apply it topically like in a serum or moisturizer you are telling your skin to create more collagen," says New York City–based esthetician Taylor Worden.

And as Nava Greenfield, M.D., board-certified dermatologist at Schweiger Dermatology Group in New York City, notes, their use so far is indeed promising—even if she acknowledges there's still more to learn. 

One concern that comes up often when discussing peptides in skin care is that there are many kinds of peptides (some better studied than others). Each is unique in its efficacy and function. So treating peptides as a monolith is a bit misleading for the consumer. To understand the nuances of peptide research, you need to get technical. 

As we've noted, many peptide-containing products are marketed as either "for mature skin" or "for barrier support." Once you see the benefits, this will make sense. 

Generally, these are well tolerated by most individuals. (After all, your body makes its own peptides.) "If you have sensitive skin or have had an adverse reaction to peptide products in the past, use caution when trying a new one," says Greenfield. "Test it out on your outer cheek or forearm for a few weeks before applying it broadly."

Peptides play nice with other ingredients and tend to be pretty stable. For that reason, they're generally OK to pair with other actives, such as antioxidants. 

If you plan to layer your peptide product with something else, just follow the general skin care step guidelines, which are as follows: face wash, toner, serum, cream, oil, and SPF. Most peptide options are going to fall in the serum or cream slot, and if it's the latter, you may consider adding another active ingredient underneath in the form of a serum. For example, you may try an antioxidant serum topped with your peptide lotion. If so, just be careful to introduce the products one at a time so your skin has time to adjust to each new product. 

Given peptides are used for their collagen-building benefits, one idea is to use them alongside other collagen-boosting ingredients. Vitamin C and E serums are some of our favorites as the antioxidants are a vital part of the collagen synthesis process. Not only is it necessary for stimulating internal collagen production, but it also helps stabilize existing collagen8 levels in the skin, essentially protecting all the hard work from the peptides.