PP405 For Hair Loss - Does it Work?
Last reviewed on 8 July 2026. We review our treatment guides every six months to keep them accurate.
Before we start on this much-discussed experimental treatment, please note that you cannot buy PP405 in the UK or anywhere else. It is a drug in early-stage development, and if it succeeds it may reach the market at some point around 2028 to 2030 from Pelage Pharmaceuticals. Anyone offering it for sale before then is running a scam and should be avoided. Always speak to your doctor before considering any form of treatment.
For the latest official updates on PP405, see Pelage Pharmaceuticals' press releases, the company developing the drug.
So what is PP405, and why has it drawn attention?
A Phase 2a randomised controlled trial in 78 men and women with androgenetic alopecia
Met its primary safety endpoint, with no systemic absorption of PP405 detected in blood
Well tolerated, with a favourable short-term safety profile
In an exploratory efficacy analysis, 31% of men with more advanced hair loss achieved a greater than 20% increase in hair density at week 8, compared with 0% on placebo
That response followed only 4 weeks of treatment, which is unusually early for a hair-loss therapy
Signs of new terminal hair growing from follicular units that were previously dormant
A first-in-class regenerative approach that targets dormant hair follicle stem cells
Designed to reactivate follicles rather than simply slow hormonal miniaturisation
Intended for both men and women, including patients underserved by current treatments
Backed by a 120 million dollar Series B financing round in October 2025
Featured at the American Academy of Dermatology Annual Meeting in March 2026
Late-stage (Phase 3) studies are expected to begin in 2026
PP405 is a topical small molecule developed by Pelage Pharmaceuticals as a regenerative treatment for androgenetic alopecia. It has drawn considerable attention because it aims to address hair loss at the level of stem cell biology, rather than focusing purely on hormones or circulation.
The company published a press release in mid 2025 with results from its trials, which you can read in the Pelage press release here. The Phase 2a trial enrolled 78 men and women with pattern hair loss across a broad range of skin phototypes and hair textures. Participants applied either PP405 or a placebo once daily for four weeks, and were then followed to week twelve.
The study met its primary safety endpoint and its secondary pharmacokinetic endpoint, with no systemic absorption of PP405 detected in blood testing. That matters when assessing a topical drug intended for long-term daily use.
Interest has been amplified by the company's financial backing. Pelage is supported by an investor syndicate led by GV, formerly Google Ventures, which backed its early Series A and Series A-1 rounds. In October 2025 the company raised a further 120 million dollars in Series B financing to fund late-stage development. Substantial investment from a major venture firm raises a company's profile in scientific and financial circles, although funding enthusiasm is not the same as robust long-term clinical data.
What captured most attention was the early clinical signal. At week eight, four weeks after treatment finished, 31% of men with a higher degree of hair loss who received PP405 achieved more than a 20% increase in hair density, whereas none of the placebo participants reached that threshold. Because efficacy was an exploratory objective in a study designed primarily to test safety, this signal is best read as encouraging rather than confirmatory. Even so, in a field where meaningful change usually takes many months, that early separation from placebo stands out.
How PP405 works in practical terms
PP405 aims to reactivate dormant but still-present hair follicle stem cells by targeting their energy pathways, rather than reducing DHT or blocking androgen receptors.
To understand PP405, it helps to know that in androgenetic alopecia the hair follicles often do not disappear entirely. In many patients, dormant follicles and stem cells remain within the scalp but have entered a prolonged inactive state, driven by a combination of age, genetics, hormonal environment, stress and environmental factors.
PP405 is designed to target the metabolic processes that regulate the activation and inactivation of hair follicle stem cells. Rather than reducing dihydrotestosterone or blocking androgen receptors, the compound aims to influence cellular energy pathways within the follicular stem cell niche, encouraging dormant follicles to re-enter the growth phase.
In practical terms, this is a regenerative strategy. Instead of shielding follicles from hormonal damage or stimulating hairs that are already active, PP405 attempts to restart follicles that have, in effect, fallen asleep.
Does PP405 regrow hair, or just slow loss?
Based on the Phase 2a data, PP405 appears to do more than slow progression, though it is too early to describe it as definitive regeneration.
Pelage reported that PP405 prompted new hair growth from follicles where no visible hair was previously present, which sets it apart from therapies that mainly thicken existing miniaturised hairs. If this is confirmed in larger trials, it would support the idea that PP405 is activating dormant follicles rather than only enhancing growth from ones that already function.
That said, the treatment period in this study lasted only four weeks, with follow-up to twelve weeks. Long-term durability, the sustainability of any response, and ongoing maintenance requirements all remain unanswered.
What evidence supports PP405 so far?
The strongest data currently available comes from the Phase 2a randomised controlled trial in 78 participants.
The drug was well tolerated throughout the study, and no systemic absorption was detected in blood testing, meeting both the primary safety and secondary pharmacokinetic endpoints. Exploratory endpoints assessing early signs of new hair growth showed a rapid and statistically significant response after one month of treatment.
At week eight, 31% of men with more advanced hair loss achieved more than a 20% increase in hair density, compared with 0% in the placebo arm. With most existing therapies, visible regrowth typically takes six to twelve months of continuous treatment, which makes this early response noteworthy. It is worth repeating that this was an exploratory finding in a small, short study, so it needs confirmation in larger trials before firm conclusions can be drawn.
An open-label safety extension is ongoing to evaluate longer-term safety. In March 2026 the programme was also featured at the American Academy of Dermatology Annual Meeting in Denver, where the concept of counting active follicular units was discussed as a way to measure follicle reactivation. Pelage has said it expects to begin late-stage (Phase 3) studies in 2026, though as of mid 2026 those studies are not yet confirmed to have started.
Where can I buy PP405 in the UK?
You cannot buy PP405 in the UK, or anywhere else, at present.
It has not been released and is still several years away in development. Anyone claiming to sell it is running a scam and should be avoided. PP405 remains an investigational drug advancing through the FDA clinical development pathway. It has not received regulatory approval and is not available on prescription or for private purchase.
If Phase 3 trials begin in 2026 and show consistent safety and efficacy, regulatory review would still take further time. Realistically, market availability would be several years away even under favourable circumstances, so a rough estimate of 2028 to 2030 depends on how long the Phase 3 trials run and how long approval takes.
If you want to follow its progress, you can sign up on the official Pelage PP405 website to be kept updated.
How PP405 compares to finasteride
Finasteride reduces the conversion of testosterone to DHT and has decades of clinical data showing it can slow the progression of male pattern hair loss. PP405 does not alter systemic hormone levels; its focus is stem cell activation rather than androgen suppression.
Finasteride aims to protect vulnerable follicles from ongoing hormonal damage, whereas PP405 aims to reactivate dormant ones. These are biologically distinct strategies, and it is not yet known whether combining hormone suppression with stem cell activation would add benefit.
How PP405 compares to minoxidil
Minoxidil works mainly by enhancing growth signalling and prolonging the anagen phase in active follicles. It does not address the hormonal drivers of loss. PP405, by contrast, seeks to influence the metabolic activation of stem cells within follicles that have become inactive.
Minoxidil usually needs prolonged continuous use before visible results appear. In the Phase 2a study, PP405 showed a measurable response within eight weeks. Whether that early response translates into sustained density over twelve months or longer remains to be seen.
Other treatments in development, such as Breezula
Other investigational therapies include Breezula, a topical androgen receptor blocker designed to stop dihydrotestosterone from activating hair follicles locally.
Where Breezula focuses on blocking androgen signalling at the receptor level, PP405 targets follicular stem cell metabolism. Both are departures from traditional oral hormone suppression, and both remain in clinical development and need larger trials before any approval.
How does PP405 compare to a hair transplant?
A hair transplant redistributes permanent donor follicles to areas of visible baldness, which avoids the need to reactivate dormant follicles.
If follicles are structurally absent, no topical therapy can recreate them. In advanced bald areas where the follicular architecture has been lost, transplantation remains the only predictable way to restore density.
PP405 may prove useful in thinning regions where follicles remain but are inactive. It is unlikely to replace surgical restoration in established baldness.
Should I add PP405 to my existing hair care routine?
At present this is not possible, because PP405 is not commercially available.
Even if it is approved in future, how it might fit into a hair care plan would depend on your stage of hair loss, how well you tolerate your existing treatments, and your long-term goals. Combination therapy may become relevant if future data supports an added benefit, but that would rely on robust Phase 3 evidence.
How PP405 is best understood today
PP405 is best understood as an early-stage regenerative therapy with encouraging preliminary data and strong safety signals in a controlled clinical setting.
The Phase 2a study showed a short treatment course, no detectable systemic absorption, and a meaningful proportion of men achieving significant density increases within weeks. At the same time, it remains investigational. The sample size was modest, the treatment window was brief, and long-term durability is unknown.
The scientific rationale is compelling and the early human data is promising, and the financial backing has amplified attention. The decisive question is whether larger Phase 3 trials will confirm a sustained, reproducible benefit across broader groups of patients over longer follow-up.
Frequently asked questions
Is PP405 safe?
In the Phase 2a trial, PP405 was well tolerated and no systemic absorption was detected in blood testing, which is reassuring for a topical drug. That said, the study lasted only four weeks, so its longer-term safety has not yet been established. Assessing this is one of the main purposes of later-stage trials.
Does PP405 work for women?
The Phase 2a trial included both men and women, and the drug is being developed for both. The density result reported so far, a greater than 20% increase at week eight, was seen in men with more advanced hair loss. Whether women benefit to a similar degree has not yet been shown, and will need to be confirmed in larger trials.
Will PP405 help a receding hairline, or only thinning areas?
PP405 is designed to reactivate follicles that are dormant but still present, so it is most likely to help in areas that are thinning rather than completely bald. Where follicles have been lost entirely, no topical treatment can recreate them, and a hair transplant remains the only predictable option.
Is PP405 approved by the FDA or the MHRA?
No. PP405 is an investigational drug still in clinical trials. It has not been approved by the FDA in the United States or by the MHRA in the UK, and it is not available on prescription.
How much will PP405 cost?
There is no price yet, because PP405 is not approved or on sale anywhere. Any figure quoted online is speculation, and, as above, anyone claiming to sell it should be avoided.
Can I take part in a PP405 clinical trial?
Pelage's trials have been run in the United States to date. You can register your interest on the official Pelage PP405 website, which is also the best way to hear if trials or access open up in the UK in future.
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