Cold atmospheric plasma devices have begun entering dermatology and aesthetic clinics over the past five years. Claims abound: promotes hair growth, activates stem cells, restores follicle health. Ozone therapy clinics and practitioners are running similar narratives. Both groups point to "plasma science" and "cellular activation." Your clients will ask about them. You need to separate the hype from what the peer-reviewed literature actually shows.
The good news: there is legitimate science here. Multiple published studies document mechanisms by which plasma devices can influence follicle biology. Clinical trials in humans show measurable hair growth outcomes. The bad news: most practitioners and vendors are conflating completely different modalities. Cold atmospheric plasma (CAP) and ozone therapy are not the same thing. The research supporting one does not support the other. And the distinction matters for your credibility and your clients' outcomes.
Here's what the current research landscape actually tells us.
What Is Cold Atmospheric Plasma?
Plasma is often called the "fourth state of matter"—beyond solid, liquid, and gas. In this context, it's an ionized gas containing free electrons, positive ions, and neutral molecules. A cold atmospheric plasma device generates this state at room temperature (unlike industrial plasma, which requires extreme heat) and delivers it to tissue without thermal damage.
Different plasma sources exist. Air-based plasma generates primarily nitrogen species and exogenous nitric oxide (eNO). Argon-based plasma generates argon metastables and argon ions. Helium-based systems exist as well. The mechanism of action depends partly on the gas source and partly on the type of delivery: direct plasma jet, indirect plasma (where plasma is generated remotely and the gas is carried to the target), or plasma-activated liquid.
What matters for hair: CAP generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) that interact with cells in the follicle microenvironment and, at the molecular level, activate specific signaling pathways involved in hair growth.
The β-Catenin Connection: Activating the Wnt Pathway
The foundational mechanism for CAP's effect on hair follicles centers on Wnt/β-catenin signaling, a pathway absolutely critical to hair follicle induction and keratinocyte proliferation during hair cycling and regrowth.
Researchers treated isolated dermal papilla cells (DPCs)—the mesenchymal signaling center of the hair follicle—with cold atmospheric microwave plasma. The result: significant upregulation of β-catenin, cyclin D1, and c-Myc expression. The team also documented increased YAP/TAZ expression, both of which amplify Wnt/β-catenin signaling downstream.
Why this matters: dermal papilla cells are responsible for instructing surrounding keratinocytes to proliferate and differentiate into hair shaft. The Wnt/β-catenin pathway is how they send that signal. When you activate β-catenin in dermal papilla cells, you amplify their ability to regenerate the follicle. This is not speculative. This is documented cell biology.
An earlier 2021 study reached the same conclusion with air-based non-thermal atmospheric plasma treatment of DPCs: activation of the Wnt/β-catenin pathway, confirmed through multiple experimental approaches. The mechanism is consistent.
Clinical Evidence: Hair Growth in Humans
In vitro work is important, but it's not clinical evidence. The question practitioners care about: does this actually make hair grow in people? There is now published human data.
Published in 2025 in the Journal of the American Academy of Dermatology, this nonrandomized controlled study documents hair growth outcomes in patients treated with a cold plasma device. This is the most recent clinical evidence in the published literature for CAP efficacy in androgenetic alopecia (AGA).
An earlier 2020 study from the same research group treated 14 patients with androgenetic alopecia using indirect CAP for 3 to 6 months. The study was primarily a tolerability assessment: did the device cause irritation, burns, or adverse effects? The answer was clear: yes, it was well tolerated. But notably, most patients also reported subjective improvement in hair appearance and fullness. This was not a randomized controlled trial with primary efficacy endpoints, but it provided preliminary evidence that the device was safe and showed signal for benefit.
You now have published clinical data showing that cold atmospheric plasma treatment of the scalp is tolerated and associated with hair growth in patients with pattern hair loss. This is not a fully characterized treatment protocol. The studies are small. Larger, randomized controlled trials are needed to establish optimal parameters, patient selection, and comparison to established therapies like minoxidil and finasteride. But the mechanism is documented, the cell biology is real, and there is human clinical signal. This is not speculative.
Beyond the Follicle: The Macroenvironment
Hair growth is not determined by the follicle in isolation. The tissue surrounding the follicle—vascularity, inflammation, oxygen tension, growth factor availability—profoundly influences whether a follicle enters anagen or rests in telogen. CAP appears to work partly at the follicle level and partly by improving the broader scalp microenvironment.
This 2021 study investigated the mechanism by which air-based non-thermal plasma promotes hair growth. They found that NTP generates exogenous nitric oxide (eNO), which drives multiple effects in the follicle microenvironment: activation of CD34+CD44+ stem cells (hair follicle stem cells), stimulation of adipogenesis (the formation of perifollicular fat, which is permissive for hair growth), and critically, increased perifollicular vascularity.
More blood flow to the follicle means more oxygen, more nutrients, and more growth factor delivery. The plasma treatment also elevated IGF-1 (insulin-like growth factor-1) and β-catenin levels locally. Normal human skin cells showed no cytotoxicity from the treatment, indicating a therapeutic window.
The Next Frontier: Plasma-Activated Hydrogels
The most recent and striking advancement in plasma science for hair is the development of plasma-activated hydrogel systems that retain reactive species and combine them with immunomodulatory agents.
Published in 2026 in Advanced Science, this study describes a system called CAPgel/IL2—cold atmospheric plasma irradiation of a tyramine-grafted hyaluronic acid hydrogel containing IL-2 (interleukin-2). The plasma treatment induces gelation of the hydrogel while maintaining both reactive oxygen species and IL-2 within the gel matrix.
In a depilated mouse model (hair was removed and then the system was applied to promote regrowth), CAPgel/IL2 showed significantly greater hair regeneration than minoxidil monotherapy or finasteride monotherapy. The treated animals achieved 100% fur coverage within 15 days, compared to incomplete regrowth with the drug controls. Mechanistically, the system increased regulatory T cell (Treg) expansion in the hair follicle microenvironment, remodeling immunity from a pro-inflammatory to a pro-regenerative state.
This is still preclinical animal work, not a human clinical trial. But it represents the frontier of where plasma science is moving: combining plasma's ability to generate reactive species with targeted delivery of immunomodulatory agents to optimize the follicle microenvironment for regeneration.
Mouse models of hair regrowth, even depilated models, do not directly translate to human androgenetic alopecia. Mouse hair cycling and regenerative capacity are different from human hair follicle biology. What this study does demonstrate is a proof-of-concept for combining plasma with targeted molecular agents to enhance regeneration. If this approach does advance to human trials, we can expect it will take years. Do not interpret this as a near-term clinical option. It is foundational research indicating where the field is headed.
What About Ozone? Where the Evidence Actually Stands
This is where clarity becomes critical. Ozone therapy is a completely separate modality from cold atmospheric plasma. They are not the same mechanism, they are not the same treatment, and the evidence supporting them is not interchangeable.
The primary human study on ozone therapy for hair loss was published in 1995. Forty-two subjects with androgenetic alopecia were treated with major autohaemotherapy with ozonated blood (drawing blood, ozonizing it, and reinfusing it) over 16 sessions. Most subjects reported marked improvement in their hair cycle. However, this study is almost 30 years old, the methodology by current standards is limited, and it has not been replicated in recent, rigorous fashion.
A 2024 literature review on ozone therapy for dermatological conditions acknowledged that ozone has documented antimicrobial, anti-inflammatory, and antioxidant properties. However, the review concluded that most ozone therapy literature suffers from significant methodological limitations, including small sample sizes, lack of controls, and inconsistent outcome measures. For hair loss specifically, the evidence base is sparse and dated.
The Hair Fiber Safety Question: Ozone and Scalp Application
There is one critical safety question that has not been adequately addressed in clinical practice: what does ozone do to the hair fiber itself?
A 2025 study using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR-ATR) examined what happens to human hair fibers when exposed to ozone at the scalp. The findings were concerning: SEM showed visible structural alterations in the hair fiber appearance. FTIR-ATR detected degradation signatures at both the cuticle layer and the cuticle-matrix complex (CMC), the adhesive zone holding the hair structure together. The spectroscopy indicated potential phase changes in alpha-helix to beta-sheet protein structure, which would affect mechanical resistance and elasticity.
The authors concluded that additional studies are needed before ozone therapy can be confidently discussed as safe for use on the scalp, given that it may damage the structural integrity of the hair fiber itself. This is not a small concern. A therapy that damages existing hair while attempting to improve growth is working against itself.
Ozone is a three-atom oxygen molecule (O3) with oxidative properties. It must be generated separately and either applied topically or introduced systemically. The evidence for hair growth is limited and dated. There are emerging safety concerns about its effects on hair fiber integrity. The mechanism for promoting hair growth in humans is not clearly established in recent literature.
Cold atmospheric plasma generates multiple reactive species (ROS, RNS, ions) in a contained system with direct application to the target. The mechanisms are documented in peer-reviewed cell biology and dermal papilla cell studies. There is recent human clinical data showing hair growth. There are no documented concerns about damage to the hair fiber. The treatment is localized to the scalp and follicle microenvironment.
These are not the same thing. Do not let vendors or practitioners conflate them. Your clients deserve clear language about what's being proposed and what evidence supports it.
What This Means for Trichologists
You will be asked about plasma devices. Aesthetic clinics are acquiring them. Some trichologists are integrating them into their practices. You need to be able to explain what cold atmospheric plasma actually does at the cellular level, what the clinical evidence shows, and how it differs from other modalities.
Know the pathway. Wnt/β-catenin signaling in dermal papilla cells, activation of hair follicle stem cells, improved perifollicular vascularity via nitric oxide generation. These are not vague claims. They are documented mechanisms in peer-reviewed journals. When you understand the biology, you can evaluate whether claims being made are consistent with the mechanism or whether they're overselling.
Acknowledge the evidence gap. We have clinical signal from small studies. We do not yet have large randomized controlled trials comparing CAP to minoxidil or finasteride, determining optimal treatment parameters, or establishing which patients respond best. The technology is advancing faster than the clinical evidence. That's okay to say out loud. It's honest, and it's accurate.
Do not conflate ozone and plasma. They are different. The ozone evidence is weak and dated. The plasma evidence is emerging but more recent. The fiber safety concerns with ozone are real. When a client asks about "plasma therapy for hair," ask clarifying questions. Are they asking about cold atmospheric plasma devices or ozone therapy? The answer determines what you should recommend.
Stay current on the literature. This field is moving fast. Studies published in 2025 and 2026 are changing what we know. Mechanisms documented in 2023 and 2024 are guiding new trials. This is exactly the kind of rapidly advancing field where your credibility as a practitioner depends on staying ahead of the marketing and actually reading the papers.
The Bottom Line
Cold atmospheric plasma devices activate Wnt/β-catenin signaling in dermal papilla cells and improve the scalp microenvironment through nitric oxide generation and immune remodeling. Human clinical studies, though small, show hair growth outcomes. The mechanisms are documented. This is real science. Ozone therapy is a separate modality with weak clinical evidence for hair growth, dated primary data, and emerging safety concerns about hair fiber integrity. They should not be conflated. The frontier of plasma science is plasma-activated hydrogels that combine reactive species with immunomodulatory agents—early preclinical work but highly promising. For trichologists, the message is clear: understand the biology, acknowledge what we know and don't know, distinguish between different modalities, and stay current on rapidly advancing research.