“Glow” skin-care treatments have skyrocketed in popularity thanks to the promise of a more youthful look. More recently the trend has morphed with another craze — injectable peptides — to create something new: the glow peptide stack, also known as the glow stack.

Some users on social media refer to the glow stack as “biohacking,” while others say it offers “full body repair” to both enhance skin and support gut health. “I feel like I have baby skin again,” one poster shared.

Despite the hype, doctors are wary. “Tread with significant caution,” says Robert Schwarcz, MD, an oculofacial plastic surgeon and facial aesthetics specialist in New York City.

Peptides are short chains of amino acids. Skin-care treatments using peptides can be topical — meaning, applied to the skin — or injected or infused.

Topical peptides, like those in “anti-aging” skin-care creams and serums, do not require approval from the U.S. Food and Drug Administration (FDA) before entering the market. “Topical peptides mainly improve the skin barrier and surface layers with limited penetration,” says Gary Goldenberg, MD, an assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai in New York City.

Topical peptides may “modestly improve” skin hydration and reduce the appearance of fine lines, possibly because of their anti-inflammatory effect, adds Krishna Vyas, MD, PhD, a plastic surgeon at Blechman Plastic Surgery in New York City. But “The outermost layer of the skin acts as a biological gatekeeper, which limits how much of any topical peptides penetrate,” he says.

Injected and infused peptides are something else entirely. “They bypass that barrier and deliver compounds directly into the bloodstream, " Dr. Vyas says.

Peptides like those in the glow stack are not regulated by the FDA to ensure safety, quality, or effectiveness. You don’t know exactly what’s in them, their potency, or whether they are impure or contaminated, any of which could result in harm.

It’s important to note that glow peptide stack injections have not been studied in clinical trials and therefore do not have scientific data to support their safe and effective use.

There is no single, standardized glow peptide stack injection. Instead, it’s a term that’s often used to market different formulations.

These are three ingredients in a typical glow peptide stack.

• GHK-Cu Some studies have linked topical creams containing this copper peptide with collagen production, tissue repair, and anti-inflammatory activity, says Anetta Reszko, MD, PhD, a dermatologist and a clinical assistant professor of dermatology at Weill Cornell Medical College in New York City. It’s important to note that the data to support GHK-Cu comes from experimental or animal research — not clinical trials in humans or injectable forms.

• TB-500 Thymosin beta-4 fragment or TB-500 is used for injury recovery and inflammation reduction, according to Dr. Reszko. Again, there are no clinical trials involving humans to support this — just some older animal studies.

• BPC-157 Also known as the “Wolverine” peptide, BPC-157 has been investigated for gut repair, tissue regeneration, and potential neuroprotective effects, “though most of the data is still preclinical or limited in scope,” Reszko says. It is currently banned by the FDA and flagged for potential safety risks.

There are a lot of claims swirling online to support glow peptide stack injections, including that these will support skin hydration and elasticity and create a luminous “glass skin” effect.

But “There is a significant lack of scientific evidence in this area,” says Chang B. Son, MD, a dermatologist at SCN Dermatology in New York and New Jersey. “Human data are limited, and large-scale clinical trials are lacking. It is important to distinguish between marketing hype and claims that are supported by scientific data.”

The combination used for glow peptide stacks does not have robust clinical evidence to support it, Reszko says, adding, “While individual peptides may have meaningful biologic activity, the way these combinations are being used is not yet standardized or thoroughly studied.” With that, it’s also unclear what the side effects may be or if you’re even getting what the label or seller claims, Dr. Goldenberg says.

Because injectable peptides are not FDA-approved, they exist in a legal gray area and are sold as research chemicals, says Dr. Schwarcz. (Again, there is not even a standard for the glow peptide stack injection, although the ingredients listed above are typical.)

Their regulatory status can vary depending on how they are sourced and administered, Reszko says.

Because peptide stack injections are not FDA-approved, “safety and efficacy data are missing,” Goldenberg says. One scientific analysis linked BPC-157 with injection site pain, a decreased sensitivity to insulin (a hormone that helps escort glucose to cells, where it’s used for energy), and water retention.

“There is a high risk of infection, contamination, incorrect dosing, and serious reactions," Goldenberg says. He also noted “a lack of medical oversight” as concerning.

"There is also no standardized protocol for many of these compounds, which increases the potential for adverse effects,” Reszko says. Stacking these peptides together is “dangerous” as well, Vyas says. “There aren’t well-established human doses for these peptides on their own, and even less is known about how they interact together,” he says.

Long-term human safety data also “does not exist” for any of these peptides when injected, Vyas says. “That doesn’t prove they’re dangerous, but it means no one can honestly tell someone they’re safe, either,” he says. “The concern is that by injecting them, people are exposing their entire body systemically to compounds that have never been rigorously tested in humans.” It’s also unclear if people with certain underlying health conditions will run a higher risk of harmful side effects from the peptide stack. There is also no standardized protocol for injecting these peptides, Reszko says.

U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. shared on the Joe Rogan Experience podcast that he plans to remove the FDA’s ban on several peptides, but also acknowledged in that interview that there isn’t robust scientific data to support their use. “Even with growing interest in peptides, these treatments should always be approached within a controlled medical setting,” Rezko says.

Doctors do not recommend trying glow peptide stack injections. “My job is to protect patients first,” Vyas says. “Until we have human clinical trials demonstrating both safety and efficacy for injectable peptide stacks, the responsible recommendation is to stay with treatments that have earned their evidence, and to be deeply skeptical of anyone offering unregulated injections based on social media trends.”

Reszko stresses that the data does not currently support the use of glow peptide stack injections. “For patients seeking improved radiance and overall skin quality, there are well-established approaches — topical antioxidants, retinoids, daily sunscreen, and in-office treatments such as microneedling or laser therapies — that provide more predictable and evidence-based results,” she says.

Overall, doctors recommend sticking with evidence-based treatment. “Your skin deserves science, not speculation,” Vyas says.

• The glow peptide stack injection is making the rounds on social media.

• Fans swear it supports skin repair and recovery, creating a youthful look.

• The treatment is not approved by the FDA, and dermatologists do not recommend it, because of a lack of evidence that it works and is safe. These treatments also come with a risk of side effects.