Verteporfin has been FDA-approved since 2000, sold as Visudyne, for photodynamic therapy in certain forms of macular degeneration. Its approved use is a two-step process: an intravenous infusion, followed 15 minutes later by a precisely timed dose of 689 nm laser light aimed at the eye. The light activates verteporfin, triggering its photodynamic effect and generating reactive molecules that selectively close off abnormal blood vessels. Without the light, verteporfin given this way does essentially nothing to the target tissue.

Separately from its light-activated photodynamic effect, laboratory researchers have used verteporfin for years as a chemical inhibitor of YAP, a protein that acts as a switch inside cells for the Hippo signalling pathway, one of the body's core regulators of tissue growth, repair, and scarring. This YAP-inhibiting property doesn't require light at all. It's this second, separate pharmacological property, not the drug's approved photodynamic use, that the hair loss application is built on.

The rationale traces to a well-regarded paper out of Michael Longaker and Geoffrey Gurtner's lab at Stanford, published in Science in 2021. The researchers were studying why some wounds heal with a scar and others, like early foetal skin, regenerate the original tissue, hair follicles, glands, and all, without one.

This is a genuinely strong result from a credible academic source, and it's the legitimate foundation everything downstream of it rests on. It is also, explicitly, mouse research. The Stanford team's own stated next step, at the time of publication, was testing in larger animals before any human trial, precisely because wound healing and scarring biology differ meaningfully between species and mice heal wounds very differently from humans to begin with.

That larger-animal step did subsequently happen.

That study was about scarless wound regeneration generally, not a demonstration of hair regrowth specifically, and it still doesn't provide clinical evidence for hair restoration in humans. It closes the large-animal gap the original Stanford team flagged, but it doesn't close the much bigger gap between pig wounds and a human scalp.

The Hippo pathway that YAP sits in isn't unique to scar-forming fibroblasts; it's a general growth-and-repair regulator active in many cell types, including some directly involved in the hair follicle itself. A 2025 paper looked specifically at one such population, and the result runs in the opposite direction from the wound-regeneration story.

These two findings aren't necessarily contradictory, YAP's role in wound-margin fibroblasts and its role in a specific follicle-resident stem cell population under low-oxygen conditions are different biological contexts, and both could be true at once. But it does mean the honest summary of verteporfin's relationship to hair follicle biology is "complicated and context-dependent," not "a growth switch," and that complexity rarely survives the trip from a scientific abstract to a hair loss forum thread.

Not the Stanford researchers, and not a pharmaceutical company. The published peer-reviewed human data so far comes from a single clinical group, the Toyos Clinic (Nashville and Memphis, better known for ophthalmology and aesthetics than hair restoration), in two separate reports published months apart in 2025.

Taken together, that's three patients, from one clinical group, across two uncontrolled reports with short follow-up. Neither establishes that verteporfin reliably regrows hair; both are consistent with it, and both are also consistent with normal post-wounding regrowth, measurement variability, or selection of favourable cases. It's a genuine starting point for a proper trial, not a substitute for one.

Beyond the published Toyos reports, at least two other hair transplant physicians have independently begun injecting compounded verteporfin into human scalp wounds, without a shared protocol, a common data standard, or, as far as AmpleLab could establish, a registered clinical trial or any peer-reviewed publication of their own. This is physician-led experimentation, not peer-reviewed evidence, and it belongs in a separate category from the reports above.

The most visible is Dr. Taleb Barghouthi, a physician based in Jordan whose own website describes the work as "the first to conduct trials on Verteporfin in the field of surgical hair restoration." The site discloses no IRB or ethics committee approval, presents no human results of its own, mentions no publication, and funds participation through a mix of public donations and direct patient payment, stating costs of $12,500 to $15,000 USD per participant, alongside "financial incentives" offered to some volunteers. That combination, paying to be experimented on while others are paid to volunteer, is a meaningful departure from how a conventional clinical trial is funded and should itself factor into how much weight anyone gives the results.

A second physician, Dr. Blake Bloxham, has also reportedly run his own small trial using a different graft-harvesting method; community-sourced reporting on hair restoration forums describes his results as noticeably less impressive than Barghouthi's. The difficulty is that these small, uncontrolled experiments use different procedures and measurement approaches, making their results difficult to compare and impossible to interpret as evidence of a reliable treatment effect.

Verteporfin's safety data, the kind regulators and physicians actually rely on, comes from its approved use: a specific intravenous dose (6 mg/m²) followed by a precisely timed laser light exposure, with the drug's principal known risk being photosensitivity serious enough that the label warns patients to avoid direct sunlight and bright indoor light for five days afterward.

Repeated subcutaneous injection directly into scalp tissue, without light activation, is a different route, a different dose pattern, and a different exposure entirely. It may well turn out to be safe, verteporfin's YAP-inhibiting property has been used in laboratory research for years, but "FDA-approved" describes the IV-and-laser protocol for an eye condition, not this specific use. Referring to verteporfin as an approved drug, without that distinction, gives the hair loss application a regulatory credibility it hasn't earned.

Verteporfin has been off-patent for years, and generic versions already exist. That creates a structural obstacle to conventional commercial development: a company funding an expensive indication-specific trial programme, the kind that would generate the controlled, statistically powered human data this compound currently lacks, would have limited exclusivity over the underlying molecule if the new use were eventually approved, since competitors could sell the same generic verteporfin for the same use immediately after approval.

This article is provided for educational purposes and does not constitute medical advice. Verteporfin is approved only for specific eye conditions and is not approved for hair loss, scalp injection, or any dermatological use by the FDA, MHRA, or any other regulatory body. Its use for hair restoration is experimental, off-label, and administered outside conventional regulated clinical trials; AmpleLab is not recommending or endorsing this use. For guidance on what's currently established for post-transplant recovery, see our post-transplant care guide. AmpleLab products are unrelated to verteporfin and are not intended to diagnose, treat, cure, or prevent any condition.

AmpleLab.