Hair loss can be deeply distressing, so it is natural that many people search online for a “cure for baldness.” The new PP405 hair regrowth treatment from UCLA has attracted attention because it tries something different: instead of just slowing loss, it aims to wake up dormant hair follicles so they start growing full hairs again. Early trials are encouraging, but PP405 is still experimental, and it will not work for everyone.
PP405 hair regrowth: how the new molecule works
For most people with androgenetic alopecia, or pattern baldness, the follicles do not die. They shrink and switch into a long resting state, producing thin, short hairs instead of thick strands. Standard treatments like minoxidil and finasteride try to nudge this cycle, but they often give modest gains and must be used for many months before results appear.
PP405 takes another path. UCLA scientists studying stem cells in mouse and human hair follicles found a metabolic “switch” that keeps these cells dormant. By designing a small molecule that hits this switch, they found a way to coax follicle stem cells back into an active state so the follicle can enter a new growth phase.
From UCLA lab discovery to Pelage Pharmaceuticals
The PP405 story began in William Lowry’s lab at UCLA, where researchers looked at how hair follicle stem cells decide when to rest and when to grow. They identified a target in the cells’ energy pathways and developed PP405 to act on it. UCLA then licensed the intellectual property around PP405 and related compounds to a startup, Pelage Pharmaceuticals, in 2018.
Pelage, backed by Google Ventures and other investors, has since raised tens of millions of dollars to move the drug through clinical trials. The company describes PP405 as a novel, non-invasive topical molecule that is applied to the scalp to reactivate dormant hair follicle stem cells and restart hair growth.
A metabolic switch in hair follicle stem cells
Hair follicle stem cells sit in a small niche in the skin and cycle between rest and activity. In pattern baldness, the growth phase gets shorter, the resting phase gets longer, and hairs become thinner over time. PP405 appears to work by shifting how these stem cells handle energy, pushing them out of dormancy. In lab studies and early human biopsies, treatment with PP405 increased markers of stem cell activation in the follicles.
Unlike hormone-blocking drugs, PP405 does not target testosterone or dihydrotestosterone (DHT) directly. That is important, because hormonal drugs such as finasteride can have sexual and mood side effects in a small share of users, and regulators now warn patients to watch for these problems.
PP405 vs older drugs like minoxidil and finasteride
Today, only two medicines, minoxidil and finasteride, are approved by the US Food and Drug Administration for androgenetic alopecia. They can slow further loss and regrow some hair, but many people find the effect limited, especially if their baldness is already advanced. Minoxidil must be applied twice a day, and finasteride is taken daily as a pill. Stopping either drug usually leads to renewed shedding.
PP405 is applied as a topical liquid once a day. Instead of changing blood hormones or simply improving blood flow, it targets the follicle stem cells themselves. If it continues to prove safe and effective, it could become a first-in-class regenerative treatment that helps some people grow new terminal hair, not just thicker “peach fuzz.” But it would still likely require ongoing use to maintain gains, just like other medical hair-loss treatments.
PP405 hair loss trials: what the studies show so far
Any new drug must move step by step through human trials. PP405 is currently in Phase 2a studies, which means it has passed initial safety tests but still needs larger trials before regulators can decide on approval.
Phase 1 safety and stem cell activation results
In its first human trial, PP405 was tested mainly for safety and biological activity. Volunteers with pattern hair loss applied the topical treatment on their scalp for a short period. According to Pelage, the Phase 1 results showed that PP405 was well tolerated and caused statistically significant activation of hair follicle stem cells in treated areas, without serious side effects.
Because this early study focused on lab markers and safety, it did not yet tell doctors how much visible hair regrowth people might expect. That requires larger, longer trials with careful counts of hair density and thickness.
Phase 2a early signs of thicker, denser hair
In 2024, Pelage launched a randomized, placebo-controlled Phase 2a trial in around 60-78 adults with androgenetic alopecia, including both women and men. Participants applied PP405 or a matching placebo to their scalp once per day for four weeks and were then followed for about three months.
The company and independent reports state that the trial met its primary safety and pharmacokinetic goals. No PP405 was detected in blood samples, which supports the idea that the drug stays local to the skin. For exploratory hair growth outcomes, early data showed that roughly 31% of men with more advanced hair loss who used PP405 achieved more than a 20% increase in hair density at week 8, compared with 0% in the placebo group.
A 20% density gain means that if a patch had 100 hairs per square centimetre at baseline, it might have around 120 after treatment. That may not sound dramatic, but for many people it can change how the scalp looks in daily life, especially when combined with styling.
Who joined the PP405 androgenetic alopecia studies
The Phase 2a study made a point of enrolling people across a wide range of skin tones and hair textures, which has not always been the case in hair loss research. Both women and men with mild to moderate pattern baldness could join, as long as their follicles were still present and capable of growth.
This matters, because androgenetic alopecia is extremely common in every group. Studies suggest that by age 70, up to 80% of men and about half of women show signs of pattern hair loss, and the condition can have strong effects on self-esteem and mood, especially for women.
What PP405 could change for pattern baldness
If future Phase 3 trials confirm the early results, PP405 could shift the hair-loss landscape in several ways. Still, it is important not to confuse “promising new option” with “cure for everyone.”
Benefits compared with current hair loss treatments
Because PP405 is non-hormonal and stays in the skin, it may avoid some of the systemic side effects linked to oral finasteride, though this will need long-term confirmation. It also appears to work faster than many existing options: visible gains were reported a few months after just four weeks of use, while many current treatments require six to twelve months of continuous therapy before changes are easy to see.
If PP405 truly reactivates follicles that had stopped producing visible hair, it could help people who feel they have run out of options after trying minoxidil, finasteride, or even hair transplant surgery. That said, early trials have been short, and we still do not know how well results hold up over years.
Limits: scarring, late-stage baldness, long-term use
PP405 can only act where follicles and stem cells are still present. In areas of long-standing, shiny baldness where the follicles have scarred or disappeared, no topical treatment is likely to restore hair. Reports also suggest that the best responses so far have been in people with mild to moderate hair loss rather than those with the most advanced thinning.
Like almost all hair-loss medicines, PP405 will probably need to be used indefinitely to keep its benefits. The hair cycle is ongoing; once the drug is stopped, the underlying genetic and hormonal forces that drive pattern baldness will still be there. This is similar to how minoxidil and finasteride must be continued to maintain results.
Side effects, costs and access questions
So far, trials report that PP405 has been well tolerated, with no serious safety signals and no drug detected in the bloodstream. But larger and longer studies are needed to rule out rare side effects. Regulators typically require multi-year data before approving a new chronic-use medicine.
Cost and access also remain open questions. Hair-loss drugs and procedures can be expensive, and many insurance plans treat them as cosmetic. If PP405 reaches the market, it may be priced like other branded dermatology treatments, and availability could vary by country. Newer treatments often reach wealthier patients first, as commenters and patient advocates rightly worry.
Other emerging hair regrowth treatments
PP405 is not the only new idea in this crowded field. Several research teams are exploring ways to regenerate or reprogram hair follicles using stem cells, growth factors and energy metabolism.
Regenerative and stem cell treatments in the pipeline
Experimental work in mice has shown that combining fat-derived stem cells with energy molecules like ATP can reverse hair loss and lead to full fur regrowth, at least in animals. Other studies aim to grow new hair follicles in lab-grown skin or to deliver pro-growth signals like SCUBE3 directly into the scalp. These approaches are still far from routine clinical use but illustrate the broader push toward regenerative solutions.
Laser and light-based therapies, platelet-rich plasma (PRP) injections, and microneedling with or without drug solutions also seek to stimulate local repair and growth, though the strength of evidence varies. People considering these should ask their doctor which methods are backed by controlled trials.
Lifestyle, hormones and why hair still matters so much
Androgenetic alopecia arises from a mix of genes, hormones, age and health factors. While you cannot change your DNA, general health habits like not smoking, eating a balanced diet, managing stress and staying active support skin and hair health in broad ways. At the same time, even perfect habits cannot fully override a strong inherited tendency to lose hair.
For many people, hair is closely tied to identity and attractiveness. Sudden or early hair loss can trigger anxiety and sadness. Recognising this emotional weight is important; wanting to treat hair loss is not vanity, it is a normal wish to feel like yourself.
How to read bold baldness headlines with care
Recent media coverage of PP405 has asked if scientists cured baldness, echoing many past stories that promised a final fix. A good rule of thumb is to look for four details in any such article: what kind of study was done (lab, animal, early human, large trial), how many people were involved, how long they were followed, and whether the treatment is approved or still in testing.
If an article does not answer those questions, treat it as early hype. With PP405, we know that Phase 2a data look promising and that Phase 3 trials are planned around 2026. That is hopeful news, but it is not the same as a widely available cure.
What you can do about hair loss right now
Even as new treatments move through trials, there are concrete steps you can take today if you are worried about thinning hair.
Seeing a dermatologist and getting a clear diagnosis
First, see a dermatologist or other qualified doctor who regularly treats hair disorders. Hair loss has many causes, including pattern baldness, autoimmune disease, hormonal problems, iron deficiency and medication side effects. A good exam, and sometimes blood tests or a small scalp biopsy, can tell these apart.
Getting the diagnosis right matters because treatments differ. For example, alopecia areata, an autoimmune condition that causes patchy loss, is treated with immune-targeting drugs rather than minoxidil or finasteride alone.
Current evidence-based treatment options
For androgenetic alopecia, current evidence-based choices include topical minoxidil (used by both sexes), oral finasteride for men, low-level laser devices, and hair transplant surgery in selected cases. Recent trials suggest that combining topical minoxidil with finasteride can improve density more than minoxidil alone, although finasteride’s side effects must be weighed.
Doctors may also discuss off-label options like low-dose oral minoxidil or dutasteride for some patients. It is wise to avoid compounded mixtures or telehealth prescriptions that downplay known risks, especially for hormone-related drugs.
Lifestyle steps, such as managing weight, sleep and stress, also support long-term health and may help you cope better with the emotional strain of hair loss. Broader evidence suggests that, for health overall, daily habits matter more than genes, even when genetics plays a strong role.
Protecting your mental health while you wait
If hair loss is making you feel anxious, ashamed or hopeless, you are not alone. Specialists note rising public anxiety about balding, fuelled in part by social media and dating apps. Talking openly with friends, partners or a therapist can help put these feelings in context and prevent them from turning into body dysmorphic disorder, a serious condition where appearance worries take over daily life.
Simple steps, like limiting time spent on hair-loss forums or comparison-heavy social feeds, can reduce stress. Some people find comfort in temporary cosmetic options such as hair fibres, careful styling or wigs while they explore medical treatments.
If you are tempted by expensive “miracle cures” online, remember that most are unproven at best and scams at worst. When in doubt, ask a medical professional which claims are backed by controlled studies.
Sources & related information
UCLA – Did UCLA just cure baldness? PP405 breakthrough treatment (2025)
This UCLA Magazine piece explains how researchers identified PP405 as a small molecule that can wake up dormant hair follicle stem cells, describes early human trial results, and stresses that the treatment will not work for everyone and still needs years of testing. The article also describes the creation of Pelage Pharmaceuticals to develop PP405 into a drug.
Pelage Pharmaceuticals / UCLA TDG – Pelage advances PP405 into Phase 2a trial (2024)
A joint release from Pelage and UCLA Technology Development Group outlines Phase 2a trial for PP405, including the goal of reactivating dormant hair follicle stem cells, inclusive recruitment of women and men of many skin and hair types, and the company’s Series A-1 funding round.
Businesswire – Positive Phase 2a clinical trial results for PP405 (2025)
This Businesswire press release reports early Phase 2a results, stating that PP405 is a topical, non-invasive small molecule that was well tolerated, showed statistically significant activation of hair follicle stem cells in Phase 1, and delivered early signs of clinically meaningful hair regrowth in people with androgenetic alopecia.
The Dermatology Digest – Regenerative medicine in action: topical PP405 shows promise in androgenetic alopecia (2025)
A feature in The Dermatology Digest summarises the Phase 2a trial, noting that PP405 met safety and pharmacokinetic endpoints, caused no detectable systemic exposure, and led about 31% of certain patients to gain more than 20% hair-density at eight weeks, with Phase 3 studies planned for 2026.
StatPearls / Medscape – Androgenetic alopecia overview and treatment – 2023–2024
These reference articles review how common androgenetic alopecia is in men and women, explain its causes, and confirm that minoxidil and finasteride remain the only FDA-approved drugs for this condition, with low-level laser therapy also used, while newer treatments like PP405 are still investigational. You can also read a clinical overview with similar conclusions.
The Washington Post – Newest side effect of hair loss: more public anxiety (2025)
A Washington Post story on the emotional toll of hair loss discusses the limits of current treatments and mentions PP405 as one of several experimental therapies now in clinical trials, stressing that they are promising but not yet cures or widely available.
Meta description (157 chars): PP405 hair regrowth treatment from UCLA may help androgenetic alopecia by reactivating dormant hair follicles, but trials and FDA approval are still ongoing.
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