But Does This Stuff Work?
On efficacy, the one rule no consumer brand can break — and the clinical data on skin, scalp and microbiome health that made me want to cry
Every time you wash with conventional soap or detergent, you strip away a layer of your skin’s natural defense. The clinical evidence on what glycolipids do instead — to your skin barrier, your scalp, and your microbiome — is remarkable. New science post up, with the data.
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The week after Christmas in 2014 we moved into our friend’s farmhouse in Charlotte, Vermont while her family enjoyed some warmer weather elsewhere. In the mornings, the winter sun poured through ancient windowpanes, each warped according to their age, and bounced off the snow so that even the ceiling glowed with blinding brightness. We would drive through farms and over a steep pass to ski at the local mountain, stop at a market on the way home to pick up local meats and cheeses for dinner, shower and watch the sunset backlight the Adirondacks across Lake Champlain before meal prep and a cocktail. Just the four of us. A magical routine.
It was Tuesday morning and I was just settling down with my coffee in the dazzling kitchen when an email popped up: “Did you see Michael Gordon in the NY Times online today?” I clicked through to read the article. The press had always loved Michael and here he had done it again — it was titled “No-Shampoo Regimens Replace the Suds.” I had tried the product just a month or so prior and had been blown away by my first shower experience. The custard-like texture, the soft silky rinse, the not-squeaky-but-still-clean finish. I had started talking with Michael about a partnership and suddenly it felt like maybe I was too late. I felt a panicky urgency, but I knew I had a bigger problem:
Erica had tried the product too and she was not sold.
The number one rule of consumer products is efficacy. They absolutely have to do what they’re intended to do, and do it well. This was a massive learning for all the early green and eco products that arrived on the market. Yes, people were excited to have healthier options. Yes, they were even willing to pay a bit more for sustainability and eco-friendliness. But if it didn’t work at least as well as the conventional standard bearer, they were simply not willing to buy it again.
It turns out Erica was not crazy and, because I know how important efficacy is, I didn’t blame her for being hesitant. Michael’s precursor to Hairstory had been around for a few years already and accumulated a decent volume of customer reviews. As one of my first diligence steps I had analyzed them thoroughly and noticed a few clear trends. What first jumped out is that the repeat purchase rate was off the charts — people loved the product and came back. Looking closer, however, I saw another nuance: some people talked about it taking a couple of weeks for them to “figure it out” before they were “hooked.”
I asked Erica to please try again.
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I recently ran the numbers on Hairstory’s reviews prior to October 2024 and found some interesting patterns. While 93% of reviewers never mentioned an adjustment or transition period, 7% did. Of those, just under 6% reported that they had struggled a bit at the outset but persevered and ultimately fell in love with New Wash. Of the remaining 1%, only 0.34% describe giving up entirely — while the rest just mention it and don’t share the outcome (though their average rating is high). What does this tell us? Some people really do struggle at the outset, but those who report are 17 times more likely to succeed than fail. That was Erica’s experience too. When she gave it more time — one whole week — she had a breakthrough and suddenly loved the outcome. I got her vote of confidence and the rest is history.
The reason I ran those numbers pre-October 2024 is because that’s when we launched Pre-Wash: our micellar cleanser, very similar to Sans Savon, that you rub into your scalp before heading into the shower. The idea was that double cleansing with Pre-Wash would reduce the instances of people having a bad experience with New Wash. The results? Since October 2024, only 2.5% of reviews mention anything about an adjustment period and only 0.52% of reviewers say they gave up — that’s just twelve people. Adding Pre-Wash into the regimen reduced the occurrence of an adjustment period by almost 60%. The bottom line: New Wash really cleans, and Pre-Wash does too.
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The first time I spoke with Dennis Zlotnik I was pacing the deck overlooking my sister-in-law’s cove in Maine and he was about ten hours into a seventeen-hour drive to drop his kids at his in-laws for the summer. Dennis was three years into his own startup — a boutique manufacturer of biolipids and biosurfactants targeting the beauty and cosmetics industry. I had been introduced through Sans Savon’s original formulator, Marc Demarais.
When Erica and I were preparing to launch Sans Savon, we were just as focused on efficacy as we had been when we founded Hairstory. While we had some clinical studies proving our naturally derived antimicrobial system was effective at removing harmful bacteria and fungi, we had no studies to prove the general cleansing efficacy and microbiome support characteristics of the glycolipids that made up our micellar cleansing system. So instead we dirtied our hands with everything we could think of, washed it off and measured the qualitative impact. Olive oil from rubbing a raw chicken? Gone. Grease from cleaning the barbeque? Gone. The smell of garlic after chopping it up? Gone. I had studied the science behind how our antimicrobial system removes the microbes you want gone without disrupting your entire microbiome, but those studies all related to their use in deodorants, not a cleanser. I was eager for more data — and I was loving what Dennis was telling me.
He had the data. Here is what it says:
Detergents in shampoo and soap erode your skin barrier. Glycolipids improve it.
The skin barrier is your body’s first line of defense — a thin, invisible shield that keeps moisture in and irritants out. Every time you wash with conventional soap or detergent, you strip away a layer of that shield. The clinical evidence on glycolipids tells a different story. In a study measuring transepidermal water loss — essentially how much moisture is escaping through your skin — a single application of a glycolipid-based body milk produced an immediate, statistically significant improvement in skin barrier function in 83% of subjects. A separate four-day hand wash study showed that moisture levels in the skin increased by more than 50% on average compared to baseline — and stayed elevated day after day with continued use. Conventional soap does the opposite: it strips moisture and the more you use it, the worse things get. Glycolipids actually repair the damage while they clean.
Detergents in shampoo and soap create inflammation. Glycolipids reduce it.
Inflammation is your immune system’s distress signal — and chronic low-grade inflammation in the skin is now understood to be a driver of everything from acne to eczema to premature aging. Conventional detergents trigger it. Glycolipids, it turns out, actively calm it. In laboratory studies using an established inflammation model, both acid and lactone sophorolipids measurably reduced three key inflammatory markers — TNF-α, COX-2 and IL-6 — in a clear dose-dependent pattern, meaning the more glycolipid applied, the greater the reduction. They outperformed a triglyceride blend control on every marker tested. This is not a marginal difference. These are the same inflammatory pathways implicated in chronic skin conditions that affect hundreds of millions of people worldwide, most of whom have been told by well-meaning dermatologists to use gentler soap.
Detergents in shampoo and soap create scalp health problems. Glycolipids reduce them.
Two of the most common scalp complaints — acne and dandruff — share a root cause: microbial imbalance. The bacteria behind acne (P. acnes) and the fungus behind dandruff (Malassezia furfur) thrive when the scalp’s natural defenses are weakened, which conventional detergents reliably do. In clinical testing, glycolipid formulations eliminated both organisms entirely within seven days — while leaving beneficial commensal bacteria unaffected. A separate four-week acne study showed near-complete resolution of active lesions, with photographic analysis measuring reductions of nearly 100% in lesion size for the most affected subjects. The dandruff study showed statistically significant improvement in 83% of subjects after just three weeks. These are not small effects. They are the kind of results that, in a pharmaceutical context, would generate serious commercial attention.
Detergents in shampoo and soap destroy your microbiome. Glycolipids leave it intact.
This may be the most important finding of all. Your skin microbiome — the community of bacteria and other microorganisms living on your skin — is not passive. They are active participants in your skin’s health, regulating barrier function, fighting pathogens and calibrating your immune response. Conventional surfactants like SLES, the workhorse detergent in most shampoos and body washes, score an “E” — the worst possible rating — on the microbiome impact scale developed by Belgian researchers to assess cosmetic ingredient safety. In head-to-head testing against SLES, glycolipids like those in Sans Savon’s formulation and in Pre-Wash scored an “A” — the best possible — across eight representative skin microbiome strains. SLES impaired nearly every strain tested, in some cases by a factor of nine or more. The glycolipids showed no meaningful impact on any of them. Put simply: they clean without collateral damage.
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When Dennis finally sent these reports over and I had the chance to read them myself, it almost made me cry. Here it was in dry, clinical black and white: the proof that I hadn’t been entirely reckless and crazy to spend over a decade of my life taking on the Sisyphean task of convincing humanity to consider changing the way they clean themselves. There actually is a better way.
I have to acknowledge that, at times, it definitely feels overwhelming.
Changing people’s behavior, their habits, is genuinely difficult. Even when all the evidence is on your side, people are reluctant to question what they’ve always done and downright resistant to actually change. That’s what makes it hard to be optimistic that we can collectively reduce our emissions, protect our remaining natural resources and preserve the incredible beauty of this planet.
But we still have to try. One small step at a time. Often over and over and over again. Reaching out to hold hands so that we don’t feel so alone. Seeking progress over perfection. Believing, because we have no other choice.
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A recent view of Lake Champlain and the Adirondacks beyond from the shore at Charlotte, Vermont.