Why Pearwood works.
The science behind the ritual — sourced honestly, written plainly.
Pearwood is built on a simple idea: the botanicals at the center of our formulation aren't decorative. They are some of the most-studied hair ingredients in modern peer-reviewed research, drawn from centuries of East Asian tradition and now examined in laboratories around the world.
What follows is what the science actually says — written plainly, sourced honestly, and free of the language traps the category usually relies on.
Studies Cited
Journals Referenced
Each Independently Studied
He Shou Wu
Polygonum multiflorumFor more than a thousand years, He Shou Wu has been the root most closely associated with hair vitality in East Asian herbalism. Modern research has spent the last two decades trying to understand why.
Studies in Life Sciences1, Evidence-Based Complementary and Alternative Medicine2, and the Journal of Advanced Pharmaceutical Technology3 have examined how He Shou Wu's signature compound — known as TSG — interacts with the same cellular pathways the body uses to produce hair pigment.
"He Shou Wu extract was shown to protect human pigment cells from oxidative stress and to increase pigment content in cultured human hair follicles."
International Journal of Cosmetic Science · 2017
Research published in the International Journal of Cosmetic Science4 has shown that He Shou Wu extract can protect human pigment cells from oxidative stress in laboratory conditions, and can increase pigment content in cultured human hair follicles.
Separate research in the Journal of Ethnopharmacology5 found that topical application of He Shou Wu extract activated the active growth phase of the hair cycle in animal studies, working through two of the most important signaling pathways in hair biology.
He Shou Wu is, by a clear margin, the most extensively researched botanical in Pearwood. It's also the reason the formulation exists in the form it does.
Panax Ginseng
Panax ginsengIf He Shou Wu is the foundation, ginseng is the proof.
Ginseng is one of the only botanicals in Pearwood with peer-reviewed human research behind it. A controlled trial published in the Journal of Ginseng Research6 examined Korean Red Ginseng in adults with hair loss and found measurable improvements over placebo. A follow-up study in the International Journal of Dermatology7 found that adding ginseng to a standard hair treatment improved results beyond the standard treatment alone.
"Traditionally-prepared red ginseng — the steamed form long preferred in East Asian medicine — outperformed unprepared root in laboratory studies."
Phytotherapy Research · Journal of Medicinal Food
Beyond the human trials, ginseng's active compounds — called ginsenosides — have been studied across more than a dozen peer-reviewed papers in journals including the Journal of Medicinal Food8, the Journal of Dermatological Science9, and Phytotherapy Research10. This research has shown that ginseng activates the same family of cellular signals that the body uses to extend the active growth phase of the hair cycle.
There is a reason ginseng has been a cornerstone of East Asian hair tradition for two thousand years. Modern research is, slowly and carefully, catching up.
Ginger Root
Zingiber officinaleGinger's role in Pearwood is honest and specific: it is here for the scalp, not the hair shaft.
Research published in Toxicology and Applied Pharmacology11 has shown that ginger's active compounds calm inflammatory signaling in human skin cells. Work in the Journal of Photochemistry and Photobiology12 has demonstrated that the same compounds activate the body's natural antioxidant defense system in skin.
"Ginger's pungent compounds are traditionally associated with warming and peripheral microcirculation — a property also observed in modern human research."
Evidence-Based Complementary and Alternative Medicine · 2018
Classic research in Food and Chemical Toxicology13 established ginger as a broad-spectrum antimicrobial — relevant to the microbial environment of a healthy scalp. And a modern human study in Evidence-Based Complementary and Alternative Medicine14 documented ginger's traditional warming property: a measurable increase in peripheral skin temperature, consistent with how it has been used in Eastern medicine for centuries.
In Pearwood, ginger does what ginger has always done well — it cares for the soil from which the hair grows.
Two omissions, deliberately made.
The two most-discussed concerns in modern hair color are ammonia and a synthetic dye called PPD. Pearwood is formulated without both. Here is what the published research says about why that matters.
of patients tested in the largest North American allergen registry react positively to PPD15 — across nearly 55,000 patients tested between 1994 and 2018.
On PPD.
PPD (para-phenylenediamine) is one of the most-studied skin allergens in modern dermatology. In the broader European population, research published in the Journal of Investigative Dermatology16 and the British Journal of Dermatology17 found that approximately 1% of all adults are sensitized to PPD — placing it in a small group of substances that exceed that threshold across an entire general population.
The European Union's Scientific Committee on Consumer Safety18 classifies PPD as an "extreme" skin sensitizer. Pearwood is formulated entirely without it.
Hair structural studies show that exposure to higher pH levels causes measurable cuticle lifting — while gentler pH ranges preserve the fiber's integrity19.
On ammonia.
Beyond its well-documented contribution to the sharp scent associated with traditional hair color, ammonia raises the pH of the formulation aggressively in order to lift the hair cuticle.
Pearwood uses a lower-alkaline system that opens the cuticle gently, allowing the formulation to do its work without the harshness traditionally associated with the category.
We are careful with the language we use,
because language matters.
Pearwood is a botanical hair treatment that renews your natural tone. It is not a medicine. It is not a treatment for any medical condition. We do not claim it regrows lost hair, reverses gray, or replaces the care of a dermatologist or trichologist.
What we do claim is that Pearwood is built around three of the most-studied botanicals in modern hair research, formulated without ammonia and without PPD, and designed to deliver visible tone renewal in a fifteen-minute ritual you can perform on your own schedule.
The research is real. The botanicals are real. The ritual is yours.
Restore your natural tone.
A quiet ritual. Fifteen minutes. The science of color renewal, made calm.
Shop Pearwood — $49References
19 Citations- 1Jiang Z et al. Life Sciences, 2009.
- 2Han Y-H et al. Evidence-Based Complementary and Alternative Medicine, 2015.
- 3Thang ND et al. Journal of Advanced Pharmaceutical Technology & Research, 2017.
- 4Sextius P et al. International Journal of Cosmetic Science, 2017.
- 5Park H-J et al. Journal of Ethnopharmacology, 2011.
- 6Oh GN, Son SW. Journal of Ginseng Research, 2012.
- 7Ryu HJ et al. International Journal of Dermatology, 2014.
- 8Park GH et al. Journal of Medicinal Food, 2015.
- 9Kim SN et al. Journal of Dermatological Science, 2015.
- 10Murata K et al. Phytotherapy Research, 2012.
- 11Park G et al. Toxicology and Applied Pharmacology, 2016.
- 12Chen F et al. Journal of Photochemistry and Photobiology B, 2019.
- 13Singh G et al. Food and Chemical Toxicology, 2008.
- 14Sugimoto K et al. Evidence-Based Complementary and Alternative Medicine, 2018.
- 15Warshaw EM et al. Dermatitis, 2023. (North American Contact Dermatitis Group, 1994 – 2018.)
- 16Diepgen TL et al. Journal of Investigative Dermatology, 2016.
- 17Diepgen TL et al. British Journal of Dermatology, 2016.
- 18European Commission Scientific Committee on Consumer Safety. Opinion on p-Phenylenediamine, SCCS/1443/11.
- 19Adav SS et al. International Journal of Cosmetic Science, 2025.
Pearwood does not claim to treat or cure any medical condition. The research cited above examines the individual ingredients in our formulation, not Pearwood as a finished product. A 48-hour patch test is required before first use.