This is Optimizer, a weekly newsletter sent every Friday from Verge senior reviewer Victoria Song that dissects and discusses the latest gizmos and potions that swear they’re going to change your life. Opt in for Optimizer here.

While scrolling through my TikTok feed, I often find myself thinking of Elizabeth Báthory. Legend has it that Báthory, a powerful 16th-century Hungarian countess, would kill virgins and bathe in their blood to retain her youth. Historians have debated whether Báthory really was a serial killer, though most agree she probably didn’t actually bathe in blood. Still, she’s what I think of anytime I see how far vanity will take us: vampire facials, snail mucin, bird poop treatments, and now Rejuran — a Korean skincare serum with the hottest new ingredient, PDRN. In case you were unaware, PDRN comes from salmon sperm.

Usually, these ads show skinfluencers with bouncy, hydrated skin extracting a clear liquid from a silver bottle. This serum, they say, is a game changer. Rubbing it into your face will promote skin rejuvenation, elasticity, and collagen production. The result is enhanced healing, improved skin texture, and reduced wrinkles, and it’s all thanks to patented science. Rejuran’s PDRN molecule is 670 times smaller than your pores, meaning enhanced absorption.

You can be the most skeptical person on the planet, but it’s hard to argue with the human desire to be young and beautiful.

“PDRN stands for polydeoxyribonucleotide, which essentially is just a DNA fragment,” says Victoria Fu, a cosmetic chemist and one of the founders behind the Chemist Confessions skincare brand. “Super old-school PDRN treatments actually come from human placenta, but now salmon sperm PDRN has become the industry standard.”

According to Fu, beauty trends like injectables often stem from the medical field. Before it became a hot skincare ingredient, PDRN was studied as an injected therapeutic treatment for conditions like diabetic foot ulcers, and there are some promising studies for injectable PDRN that suggest it could be helpful for wound healing — though PDRN injectables haven’t been FDA-approved in the US. Generally speaking, injectables are considered more effective for rapid, dramatic, and structural changes, as they’re able to deliver ingredients deeper into the skin. Injectable hyaluronic acid, for instance, is more effective at restoring volume than topical hyaluronic acid.

Online, PDRN started gaining notoriety a few years ago as skinfluencers shuttled themselves to South Korea for salmon DNA facials. In the typical video, these beauty influencers would giggle. Come with me to get a salmon sperm facial! Usually, a doctor is shown injecting PDRN into the skin every few millimeters until the influencer’s face is riddled with tiny, swollen mounds. It hurts so much! Recovery takes so long! But just LOOK at this glow!!!

The painful treatment blew up once celebrities like Kim Kardashian and Jennifer Aniston admitted to incorporating salmon sperm facials into their routines. And then, about a year ago, Rejuran — the company behind the injections — announced a topical version. No scary needles, no need to fly to Korea, and a bottle costs about $52, whereas the facial could run anywhere from $500 to $700. Now, you can find PDRN in all kinds of skincare products ranging from eye creams to sunscreen.

Despite authoring this newsletter, I’m not immune to wellness fads. I covet glass skin like any other vain 30-something afraid of the harsh ravages of time. I’ve bought the stupid TikTok skincare wand that influencers said was “clinically proven” and that Hailey Bieber uses. I reviewed its clinical studies on electroporation — microcurrents that supposedly tear tiny holes in your skin to help products absorb better — and knew it was dubious (if relatively harmless).

Which is to say, I knew it was a red flag when I heard an influencer in a Rejuran ad say the product was “clinically proven,” but I bought a bottle anyway. I’ve used two bottles of Rejuran’s topical ampoule and other skincare products marketing hot new ingredients like volufiline, because that’s the power of science-adjacent wellness marketing. (Volufiline is a new plant-based compound that’s marketed as “topical filler” because it stimulates fat cell production.)

Still, if you truly could replicate injectable results in an easily accessible serum — that’s a compelling claim. So I asked Fu if any of the claims about topical PDRN being as effective as injected skincare treatments held water.

“There’s some early research supporting PDRN in medical and aesthetic procedures, but evidence for topical PDRN is still very limited,” says Fu. “A serum cannot be a non-invasive substitute for an injectable procedure.”

The reason is straightforward. Even if there’s evidence that PDRN itself could be an effective ingredient, the mode of delivery matters.

“Injectable treatments deliver material directly into skin tissue at concentrations and depths topical products simply won’t be able to achieve,” says Fu.

But silly things like facts aren’t enough to stop skincare brands from jumping on experimental fads so long as they’re not technically harmful.

Just the other day, I was served a video from megaviral beauty influencer Mikayla Nogueira announcing to her 17 million followers that she’s launching a salmon-derived PDRN face ampoule and eye serum for her own cosmetics line.

“A science-backed duo powered by PDRN that is going to lift, firm, plump your skin plus so much more. Not to mention these products are made in Korea, dermatologist tested, clinically tested, and proven to do exactly what they say they’re going to do,” Nogueira says in the ad. She goes on to say that she worked with Korean cosmetics chemists, and uses phrases like “low molecular weight” and “efficacious” levels.

I have no doubt Nogueira believes in PDRN products. But as I wrote in a recent Optimizer, “clinically tested” and “science-backed” are marketing phrases that don’t always mean what you think.

Meanwhile, other brands are advertising less icky versions of PDRN derived from plants. There are ginseng-derived PDRN products on the market, like the VT Cosmetics PDRN Essence 100, and the Medicube PDRN Pink Peptide Serum derived from roses. Supposedly, these brands would have you believe plant-based PDRN is just as effective and a vegan alternative.

“PDRN source, purity, molecular size, and stabilization all matter,” says Fu. “‘Plant-based PDRN’ is a bit of a marketing gray area. It may be DNA fragments, but it’s not automatically equivalent to the clinical material studied in medical literature. Two products can list PDRN and behave very differently. The good news is we are seeing more studies come out on these plant PDRNs, so hopefully we can better gauge these different sources soon.”

Fu says all things considered, PDRN is a “relatively vanilla” skincare active that’s unlikely to irritate your skin and is fine for curious skincare hobbyists to experiment with. But that also means it’s not a foundational part of any skincare routine. Things like sunscreen, moisturizers, and well-studied actives like retinoids are more likely to do the heavy lifting in any regimen. Like most things in the wellness space, the main harm that PDRN poses is to your wallet. Fu says that consistency and patience are the key to getting real, long-term results. (Unfortunately, these are also the two things most consumers would like to bypass.)

“Social media has made it possible for consumers to hear from industry insiders like ourselves,” Fu says, referring to herself and her partner, Gloria Lu. In addition to running their own cosmetics brand, the two chemists also write a skincare science education blog and host a podcast. “But the flip side is that consumers will also hear a LOT of noise and contradicting information from all sorts of directions.”

Fu says the smart thing to do is look at any testing a brand is willing to share and look for quantifiable grading metrics over consumer perception. As in, “34 percent improvement in elasticity” is a more meaningful claim than “90 percent of users agree they saw an improvement in skin hydration in two weeks.” Before and after pictures, she says, can also be misleading due to inconsistent lighting or face angles. If a claim sounds too good to be true, it likely is.

“We try to remind everyone to refrain from a ‘knee-jerk’ reaction and not to let the trends distract you from sticking to the fundamentals of your routine,” says Fu.

Having spent the past three months slathering a salmon sperm serum on my face, I honestly couldn’t tell you if it’s improved my skin. Maybe it’s a smidge glowier. I think it helped with one stubborn acne scar. I knew that I wouldn’t see dramatic results going in, just as I knew that the trendy volufiline serums that skinfluencers claim are “filler in a bottle” wouldn’t fix my undereyes. Is it egregious that I know better and still partook? Maybe. But to Fu’s point, I’m religious about the fundamentals — sunscreen, moisturizer, and as of recently, tretinoin, which I incorporated after consulting my dermatologist. The point is that I’ve done my homework and made an informed choice.

It just so happened that this time, I thought experimenting with salmon jizz serums was harmless fun.

Follow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.

• Victoria SongClose

  Victoria Song

  Senior Reviewer, Wearable Tech

  Posts from this author will be added to your daily email digest and your homepage feed.

  FollowFollow

  See All by Victoria Song

• ColumnClose

  Column

  Posts from this topic will be added to your daily email digest and your homepage feed.

  FollowFollow

  See All Column

• HealthClose

  Health

  Posts from this topic will be added to your daily email digest and your homepage feed.

  FollowFollow

  See All Health

• OptimizerClose

  Optimizer

  Posts from this topic will be added to your daily email digest and your homepage feed.

  FollowFollow

  See All Optimizer

• ScienceClose

  Science

  Posts from this topic will be added to your daily email digest and your homepage feed.

  FollowFollow

  See All Science