PP405 — Safety, Research, Risks & Legal Status

Not medical advice. PP405 is discussed here for informational and harm-reduction purposes only. We do not endorse use, and any dosing context is informational, not a protocol.

Also known as	PP-405, PP 405 (developed by Pelage Pharmaceuticals; derived from the MPC-inhibitor chemotype exemplified by UK-5099 / JXL001)
Category	Research Chemical
Drug class	Dual mitochondrial pyruvate carrier (MPC1/MPC2) inhibitor; small molecule
Developer	Pelage Pharmaceuticals (UCLA spinout, founded 2018)
Route	Topical scalp gel (reported ~0.05%), once daily
Indication	Androgenetic alopecia (male- and female-pattern hair loss)
Trial stage	Phase 1 complete; Phase 2a reported June 2025 (n=78); Phase 3 planned 2026
Regulatory status	Investigational; not FDA-approved; not a dietary supplement; not for sale
US legal status	PP405 is an investigational drug, not an FDA-approved product and not a lawful dietary supplement. As of mid-2026 it exists only inside Pelage Pharmaceuticals' clinical program (Phase 1 completed, Phase 2a reported June 2025, Phase 3 planned for 2026) and is not sold, prescribed, or available through any legal channel. The exact chemical structure is proprietary and undisclosed. Any product marketed online as "PP405" outside of a Pelage-sponsored trial is unverified and not the genuine investigational compound. This entry is informational only; Peptropix does not sell PP405 or any research chemical.

What is PP405?

PP405 is a topical small-molecule candidate for androgenetic alopecia (male- and female-pattern hair loss) being developed by Pelage Pharmaceuticals, a UCLA spinout. It is described as a dual mitochondrial pyruvate carrier (MPC1/MPC2) inhibitor formulated as a low-concentration scalp gel (reported at 0.05%, once daily). The proposed idea is to metabolically "reactivate" dormant hair follicle stem cells rather than block DHT (finasteride) or act as a vasodilator/K-channel opener (minoxidil). It is early-stage and investigational, with human efficacy data limited to a small Phase 2a readout.

How it works

PP405 is described as a dual inhibitor of the mitochondrial pyruvate carrier (MPC1 and MPC2), the transporter that shuttles pyruvate into mitochondria for oxidative metabolism. By blocking pyruvate entry, the proposed mechanism diverts metabolism toward the cytoplasm: pyruvate and lactate dehydrogenase (LDH) activity rise, intracellular lactate and glycolysis increase, and this metabolic shift is thought to push quiescent (telogen) hair follicle stem cells into an activated, growth (anagen) state. This builds on UCLA research (foundational work reported around 2017) showing that LDH activity and lactate act as a metabolic switch for hair follicle stem cell activation, and on the earlier MPC-inhibitor tool compound UK-5099, which accelerated hair growth in mice by the same lactate-driving logic. The mechanism is well-motivated preclinically but its translation to durable human hair regrowth remains to be confirmed in larger trials.

Background & history

The science traces to UCLA, where Bill Lowry, studying hair follicle stem cells, observed unusually high lactate dehydrogenase activity in active follicles; work by Lowry, Heather Christofk, and colleagues (reported around 2017) established lactate/LDH as a metabolic switch for follicle stem cell activation, using MPC inhibition (including the classic tool compound UK-5099) to drive lactate and stimulate hair growth in mice. Pelage Pharmaceuticals was spun out of UCLA in 2018 by Lowry, Christofk, and chemist Michael Jung; the company name comes from the French pelage ("coat of fur") and PP405 is reportedly named after the company and the 405 freeway. First-in-human trials began around 2023, Phase 2a topline results were announced in June 2025, and Pelage stated it plans to begin Phase 3 in 2026. The program has drawn significant venture funding (reported rounds led by Google Ventures, with cumulative financing cited around 120 million dollars) and mainstream press attention.

What the research says

Human data are early and thin. A Phase 1 study reported the drug was well tolerated, achieved its target pharmacokinetic profile with no detectable systemic (blood) drug levels, and produced a statistically significant increase in Ki67 (a proliferation marker) in treated follicles within about seven days, interpreted as stem-cell engagement. The Phase 2a trial was a randomized, double-blind, placebo-controlled study in 78 adults with androgenetic alopecia (men and women, diverse skin phototypes and hair textures), applying PP405 or placebo once daily for 4 weeks with follow-up to 12 weeks. Per the sponsor's June 2025 announcement, the study met its primary safety endpoint and secondary PK endpoint (no systemic absorption), and in a subgroup of men with more advanced loss, 31% of PP405-treated participants showed a greater than 20% increase in hair density at week 8 versus 0% on placebo. These are company-reported topline figures from a small, short trial; results have been publicized largely through press releases and conference/media coverage rather than a full peer-reviewed Phase 2a publication, and no robust large-scale, long-term human efficacy or durability data exist yet.

Reported effects

Reported goal: reactivation of dormant hair follicle stem cells and induction of new hair growth in androgenetic alopecia
Early increase in follicular proliferation marker Ki67 within ~7 days in Phase 1
In Phase 2a, a subgroup of men with advanced loss showed >20% hair-density increase at week 8 (company-reported)
New terminal hair described in some previously bald areas, suggesting a regenerative (not purely cosmetic) effect if replicated
Designed for negligible systemic exposure, so systemic hormonal or sexual side effects seen with oral options are not expected by the mechanism
All effects above are preliminary, short-term, and from small studies; not established, not durable-confirmed

Dosing & administration (informational)

Informational only, not a protocol and not usable guidance. The formulation described in reporting is a low-concentration topical scalp gel (approximately 0.05%) applied once daily, with the Phase 2a trial using a 4-week once-daily application window followed out to 12 weeks. These figures describe a controlled clinical trial regimen for the genuine investigational compound, which is not commercially available; they are not a recommendation, and no equivalent self-administration is possible or advisable outside a sponsored trial.

This is general research/context information, not medical advice or a recommended protocol.

Safety & side effects

Investigational drug with a very limited human safety database (Phase 1 plus one ~78-person Phase 2a); long-term safety is unknown
Reported safety advantage is the absence of detectable systemic absorption, which is intended to avoid the systemic effects of oral antiandrogens; this is based on early data only
No systemic adverse events were reported in early trials, but rare or delayed effects cannot be excluded from small, short studies
Local scalp effects (irritation, redness, application-site reactions) are the plausible risk category for any topical gel and are not fully characterized publicly
Unlikely to help where follicles are scarred or permanently lost; the mechanism requires intact, merely dormant follicles
Because the true compound is not commercially available, anything sold as PP405 online is unverified and potentially unsafe or mislabeled
Not evaluated for use in pregnancy, breastfeeding, or pediatric populations

Drug & supplement interactions

F
o
r
m
a
l
d
r
u
g
-
i
n
t
e
r
a
c
t
i
o
n
s
t
u
d
i
e
s
f
o
r
P
P
4
0
5
h
a
v
e
n
o
t
b
e
e
n
p
u
b
l
i
c
l
y
r
e
p
o
r
t
e
d
.
B
e
c
a
u
s
e
e
a
r
l
y
d
a
t
a
i
n
d
i
c
a
t
e
n
e
g
l
i
g
i
b
l
e
s
y
s
t
e
m
i
c
a
b
s
o
r
p
t
i
o
n
,
s
y
s
t
e
m
i
c
p
h
a
r
m
a
c
o
k
i
n
e
t
i
c
i
n
t
e
r
a
c
t
i
o
n
s
a
r
e
e
x
p
e
c
t
e
d
t
o
b
e
l
i
m
i
t
e
d
b
y
t
h
e
s
p
o
n
s
o
r
,
b
u
t
t
h
i
s
i
s
u
n
c
o
n
f
i
r
m
e
d
a
n
d
d
o
e
s
n
o
t
a
d
d
r
e
s
s
l
o
c
a
l
s
c
a
l
p
i
n
t
e
r
a
c
t
i
o
n
s
w
i
t
h
c
o
n
c
u
r
r
e
n
t
l
y
a
p
p
l
i
e
d
t
o
p
i
c
a
l
s
.
H
o
w
P
P
4
0
5
w
o
u
l
d
c
o
m
b
i
n
e
w
i
t
h
s
t
a
n
d
a
r
d
h
a
i
r
-
l
o
s
s
t
h
e
r
a
p
i
e
s
(
t
o
p
i
c
a
l
m
i
n
o
x
i
d
i
l
,
o
r
a
l
o
r
t
o
p
i
c
a
l
f
i
n
a
s
t
e
r
i
d
e
/
d
u
t
a
s
t
e
r
i
d
e
)
h
a
s
n
o
t
b
e
e
n
e
s
t
a
b
l
i
s
h
e
d
i
n
t
r
i
a
l
s
.
A
n
y
o
n
e
i
n
a
c
l
i
n
i
c
a
l
s
t
u
d
y
s
h
o
u
l
d
f
o
l
l
o
w
t
h
e
p
r
o
t
o
c
o
l
a
n
d
d
i
s
c
l
o
s
e
a
l
l
c
o
n
c
o
m
i
t
a
n
t
p
r
o
d
u
c
t
s
t
o
t
h
e
i
n
v
e
s
t
i
g
a
t
o
r
s
.

Who should avoid it

Anyone outside a legitimate Pelage-sponsored clinical trial (there is no lawful or verified supply)
People whose hair loss is due to scarring alopecia or fully lost/scarred follicles, where a stem-cell reactivator is not expected to help
Anyone tempted to buy grey-market 'PP405' from research-chemical vendors, since authenticity cannot be verified
Pregnant or breastfeeding individuals, given the absence of any safety data in these populations
Those seeking an established, evidence-backed treatment now, who are better served by therapies with regulatory approval and long-term data

How it is commonly combined

No stacking or combination guidance can be given. PP405 is investigational and not available; combination regimens (for example with minoxidil or finasteride) have not been tested or reported, so any "stack" would be speculative and unsupported by evidence. Peptropix does not provide combination protocols for unapproved compounds.

Legal & regulatory. PP405 is an investigational drug, not an FDA-approved product and not a lawful dietary supplement. As of mid-2026 it exists only inside Pelage Pharmaceuticals' clinical program (Phase 1 completed, Phase 2a reported June 2025, Phase 3 planned for 2026) and is not sold, prescribed, or available through any legal channel. The exact chemical structure is proprietary and undisclosed. Any product marketed online as "PP405" outside of a Pelage-sponsored trial is unverified and not the genuine investigational compound. This entry is informational only; Peptropix does not sell PP405 or any research chemical.

Quality & harm reduction

T
h
e
r
e
i
s
n
o
l
e
g
i
t
i
m
a
t
e
c
o
n
s
u
m
e
r
s
u
p
p
l
y
o
f
P
P
4
0
5
.
I
t
i
s
a
p
r
o
p
r
i
e
t
a
r
y
i
n
v
e
s
t
i
g
a
t
i
o
n
a
l
m
o
l
e
c
u
l
e
w
h
o
s
e
e
x
a
c
t
s
t
r
u
c
t
u
r
e
h
a
s
n
o
t
b
e
e
n
d
i
s
c
l
o
s
e
d
,
s
o
n
o
t
h
i
r
d
p
a
r
t
y
c
a
n
a
u
t
h
e
n
t
i
c
a
t
e
a
p
u
r
p
o
r
t
e
d
s
a
m
p
l
e
a
g
a
i
n
s
t
a
r
e
f
e
r
e
n
c
e
s
t
a
n
d
a
r
d
.
A
n
y
v
i
a
l
,
g
e
l
,
o
r
p
o
w
d
e
r
o
f
f
e
r
e
d
b
y
a
r
e
s
e
a
r
c
h
-
c
h
e
m
i
c
a
l
v
e
n
d
o
r
a
s
"
P
P
4
0
5
"
c
a
n
n
o
t
b
e
v
e
r
i
f
i
e
d
a
s
t
h
e
g
e
n
u
i
n
e
P
e
l
a
g
e
c
o
m
p
o
u
n
d
a
n
d
m
a
y
b
e
a
d
i
f
f
e
r
e
n
t
M
P
C
i
n
h
i
b
i
t
o
r
(
f
o
r
e
x
a
m
p
l
e
t
h
e
o
l
d
e
r
t
o
o
l
c
o
m
p
o
u
n
d
U
K
-
5
0
9
9
)
,
a
n
a
n
a
l
o
g
,
o
r
a
n
i
n
e
r
t
o
r
c
o
n
t
a
m
i
n
a
t
e
d
p
r
e
p
a
r
a
t
i
o
n
.
T
h
e
o
n
l
y
t
r
u
s
t
w
o
r
t
h
y
s
o
u
r
c
e
o
f
t
h
e
a
c
t
u
a
l
d
r
u
g
i
s
e
n
r
o
l
l
m
e
n
t
i
n
a
P
e
l
a
g
e
-
s
p
o
n
s
o
r
e
d
c
l
i
n
i
c
a
l
t
r
i
a
l
.

Safer, legal alternative we recommend

Botani-GLOW Up. For the same hair-growth goal, our topical botanical hair serum is a legal, over-the-counter option you can actually buy today.

See our recommended pick

Find PP405 →

Know your numbers before you research

Order your own bloodwork online — hormone, metabolic and inflammation panels, no doctor visit needed. Know your baselines before and during any protocol. Independent bloodwork is the cheapest insurance there is.

Get tested with Ulta Lab Tests →

Frequently asked questions

Is PP405 approved or available to buy?

No. PP405 is an investigational drug still in clinical trials (Phase 2a reported in 2025, Phase 3 planned for 2026). It is not FDA-approved, not a dietary supplement, and not legally sold. The only access to the genuine compound is through a Pelage-sponsored trial. Anything sold online as 'PP405' is unverified.

How is PP405 different from minoxidil and finasteride?

It targets a different biology. Finasteride blocks DHT and minoxidil is a topical vasodilator/potassium-channel opener; PP405 is proposed to work metabolically by inhibiting the mitochondrial pyruvate carrier to raise lactate and reactivate dormant hair follicle stem cells. Whether that translates into better or more durable regrowth than existing options is unproven and awaits larger trials.

What did the Phase 2a trial actually show?

In a randomized, double-blind, placebo-controlled study of 78 adults using the gel once daily for 4 weeks, the company reported it met its primary safety endpoint with no detectable systemic absorption, and that in a subgroup of men with more advanced loss, 31% had a greater than 20% increase in hair density at week 8 versus 0% on placebo. These are small, short-term, company-reported topline results, not a definitive efficacy dataset.

Is PP405 safe?

The human safety database is very limited (Phase 1 plus one ~78-person Phase 2a). Early data reported no systemic adverse events and no measurable blood levels, which is the main claimed advantage over oral drugs, but long-term and rare-event safety is unknown. This is not medical advice; safety questions should go to a licensed clinician.

What is the dose?

We do not provide dosing guidance. Reporting describes a roughly 0.05% topical gel applied once daily in trials, but that describes a controlled study of the real investigational compound, not a protocol you can follow. There is no safe or verified way to self-administer PP405, and dosing decisions belong with a clinician and trial investigators.

Will PP405 regrow hair on a fully bald scalp?

Likely not where follicles are scarred or permanently lost. The proposed mechanism reactivates dormant but intact follicles, so areas with viable, merely resting follicles are the plausible targets. Regeneration of terminal hair in some previously thin/bald areas was reported in early data, but this is preliminary and not established.

References & further reading

PubMed: lactate dehydrogenase activity hair follicle stem cell activation
PubMed: mitochondrial pyruvate carrier inhibitor UK-5099 hair follicle
ClinicalTrials.gov: PP405 androgenetic alopecia Pelage
PubMed: PP405 Pelage topical androgenetic alopecia hair follicle stem cell
ClinicalTrials.gov: Pelage Pharmaceuticals hair loss MPC inhibitor phase 2