Peptide

Dihexa

Also known as

PNB-0408 · MM-201 (early lab designation in some histories) · N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide · N-hexanoic-tyrosine-isoleucine-(6) aminohexanoic amide · Dihexa peptide · Dihexa oligopeptide · Angiotensin IV analog (Dihexa) · Nle1-Ang IV–derived analog (Dihexa) · HGF/c-Met potentiator (Dihexa discussions) · ATH-1017 / fosgonimeton (related clinical candidate — not identical)

Community talk. May contain inaccuracies. Not medical advice. Not a protocol. Not for human or animal use.

What it is

Experimental nootropic	An altered angiotensin-IV-derived molecule discussed for memory, learning and verbal fluency.
Brain-connection claims	The proposed connection-building story comes from animal/cell work. A central mechanism paper was retracted and the original paper carries a concern notice.
Routes differ	Oral capsules/tablets and skin delivery, often with DMSO, are different formulations; their milligrams are not proven equivalent.

Notes

An altered peptide-derived molecule. Dihexa was developed from angiotensin IV, a short signaling peptide. Online discussions often put it beside other nootropics, meaning substances people explore for thinking, memory or concentration. McCoy 2013: rat and cell work (Animal context · Accessed 2026-09-30)

Dihexa is an experimental compound discussed for memory, learning and verbal fluency. Biohackers often describe a gradual cognitive change rather than a stimulant buzz, but actual accounts range from striking improvement to no benefit or fatigue. The “brain repair” language is a community claim, not an established human treatment.

The “new connections” story. The appeal is that it might help brain cells form connections, making learning easier. That idea comes from animal/cell work and online interpretation. A central mechanism paper was retracted, and the original characterization paper carries a Notice of Concern. Retraction of the 2014 HGF/c-Met mechanism paper (Official context · Accessed 2026-09-30) · Journal Notice of Concern: McCoy 2013 (Official context · Accessed 2026-09-30) · McCoy 2013: rat and cell work (Animal context · Accessed 2026-09-30)

Oral and transdermal accounts differ. Capsules/tablets are swallowed; transdermal accounts involve delivery through skin, often with DMSO as a carrier. They are different formulations, and reported milligrams cannot establish equivalent absorption. Dihexa two-week report (Community discussion · Accessed 2026-09-30) · Long-form nootropic user account (Personal report · Accessed 2026-09-30)

Source context — McCoy 2013: rat and cell work: Full text retrieval blocked/500 this turn. Exact PK locator preserved from prior review, not freshly rechecked; paper has Notice of Concern. Not human kinetics.

Source context — Retraction of the 2014 HGF/c-Met mechanism paper: Bibliographic record, not full notice; no figure/fraud details inferred.

Source context — Journal Notice of Concern: McCoy 2013: Notice verifies integrity status, not any dosing or timing number.

Source context — Dihexa two-week report / Long-form nootropic user account: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

What people notice

Memory and engagement	Favorable accounts describe easier recall, smoother conversations, curiosity and creativity.
Performance without a feeling	One two-week user reports better chess while feeling unchanged and occasionally using other nootropics.
Fatigue or fading effect	Oral users report tiredness; another contributor felt stimulation for two days, then nothing across about fifteen later uses.

Notes

Recall, learning and verbal fluency. Favorable nootropic accounts describe easier recall, connecting ideas and smoother conversations. One creator noticed better productivity and memory around week three; others describe little or no change. Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30) · Long-form nootropic user account (Personal report · Accessed 2026-09-30) · Dihexa experiences and nonresponse (Community discussion · Accessed 2026-09-30)

Curiosity and everyday engagement. A strong transdermal account describes more interest in learning and creativity. A Dihexa/NSI-189 log describes easier habit changes and better mood, but the combination cannot isolate Dihexa. Long-form nootropic user account (Personal report · Accessed 2026-09-30) · Dihexa and NSI-189 cycle log (Community discussion · Accessed 2026-09-30)

Subtle changes without a different feeling. The two-week author reported better chess performance while feeling unchanged. Occasional other nootropics, practice and day-to-day variation remain competing explanations. Dihexa two-week report (Community discussion · Accessed 2026-09-30)

An early symptom is not cognitive improvement. The oral 4 mg/8 mg commenter felt tired roughly two hours later. That is an adverse-response timeline, not evidence of a two-hour memory-benefit onset. Dihexa two-week report (Community discussion · Accessed 2026-09-30)

Some early effects disappear. One contributor felt stimulation on the first two days, then nothing over about fifteen later uses. Persistent learning gains, ongoing stimulation and bodily drug half-life are separate questions. Dihexa experiences and nonresponse (Community discussion · Accessed 2026-09-30)

Source context — Biohackingu Dihexa mini-guide / Long-form nootropic user account / Dihexa experiences and nonresponse / Dihexa and NSI-189 cycle log / Dihexa two-week report: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Doses people talk about

Oral charts	About 2–10 mg/day, with separate 10–20 mg charts. Direct oral 4 mg and 8 mg accounts describe fatigue; a 5 mg/day report leaves route unstated.
Intermittent accounts	5 mg two or three times weekly in one account; 10 mg every other day with NSI-189 in another. Routes were unstated.
Transdermal accounts	Legacy amounts around 1–5 mg coexist with reports of 15–30 mg every 3–5 days or 25–40 mg every 8–10 days. These do not establish oral equivalents.

Notes

Oral charts: about 2–10 mg per day. The preserved community record contains this band and higher 10–20 mg charts. Direct oral commenters describe 4 mg and 8 mg with fatigue; the two-week author names 5 mg daily but does not explicitly state the route. Dihexa two-week report (Community discussion · Accessed 2026-09-30)

Intermittent reports: 5–10 mg, several times weekly or every other day. The mini-guide author reports 5 mg 2–3 times/week, route unstated. A separate stack log names 10 mg every other day with NSI-189; these are different schedules and people. Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30) · Dihexa and NSI-189 cycle log (Community discussion · Accessed 2026-09-30)

Biohackingu: personal 5 mg 2–3 times/week, four weeks on/four off, route unstated; felt better energy/productivity/recall about week three; broader 5–10 mg chart and proposed loading are separate. Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30)

OP: Dihexa 10 mg every other day, route unspecified, alongside NSI-189; repeats twelve-day half-life; two-week habit/mood update then weekly Dihexa intention. Dihexa and NSI-189 cycle log (Community discussion · Accessed 2026-09-30)

Transdermal amounts span much wider ranges. Legacy notes include about 1–5 mg. Higher accounts describe 15–30 mg every 3–5 days or 25–40 mg every 8–10 days. They do not establish a standard dose, a preparation recipe or equivalence to capsules. Long-form nootropic user account (Personal report · Accessed 2026-09-30) · Dihexa two-week report (Community discussion · Accessed 2026-09-30)

Source context — Dihexa two-week report / Biohackingu Dihexa mini-guide / Dihexa and NSI-189 cycle log / Long-form nootropic user account: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Half-life, onset & duration

Felt onset	Cognitive changes appear in week two or around week three in individual reports. Fatigue about two hours after oral use is an adverse timeline, not memory improvement.
Felt duration	One transdermal user reports effects through an 8–10-day interval. Others report fading or no sustained effect; no dependable one-dose window emerges.
Half-life	The circulated 12–13-day figure comes from rat IV research, not human oral or transdermal measurements. Human timing claims remain disputed.

Notes

Benefits described after days to weeks. One creator noticed changes around week three; the chess account noticed a performance difference in week two without feeling different. Some accounts instead describe early effects or nothing after repeated use. Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30) · Dihexa two-week report (Community discussion · Accessed 2026-09-30) · Dihexa experiences and nonresponse (Community discussion · Accessed 2026-09-30)

Persistence varies; no dependable one-dose window. A transdermal contributor reports effects throughout an 8–10-day interval. A separate strong account describes lasting changes that became less intense over time. Neither establishes how long another person would benefit. Dihexa two-week report (Community discussion · Accessed 2026-09-30) · Long-form nootropic user account (Personal report · Accessed 2026-09-30)

“About 12–13 days” is widely circulated lore. The stack log repeats around twelve days. Its underlying source is rat IV pharmacokinetics, not human oral or transdermal measurement. Keep the community claim visible without treating it as a human clearance clock. Dihexa and NSI-189 cycle log (Community discussion · Accessed 2026-09-30)

The interpretation is disputed. The two-week thread includes both long-half-life arguments and a contrary short-elimination claim. Neither commenter measured human kinetics; feeling an effect between doses cannot settle the half-life. Dihexa two-week report (Community discussion · Accessed 2026-09-30)

Source context — Biohackingu Dihexa mini-guide / Dihexa two-week report / Dihexa experiences and nonresponse / Long-form nootropic user account / Dihexa and NSI-189 cycle log: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Cycles people discuss

Community templates	Two weeks on/two off and longer 4–8-week blocks with multi-week breaks appear in the preserved discussion.
Individual patterns	One creator describes four weeks on/four off at 5 mg two or three times weekly. A high-transdermal account proposes a five-week maximum; neither validates a washout.

Notes

Two weeks on / two weeks off appears in the old discussion. The preserved record also includes longer 4–8-week blocks and multi-week breaks. These are community templates, not a validated washout or a claim that short courses eliminate risk.

Four weeks on / four weeks off: one creator’s pattern. The mini-guide author describes that course with 5 mg 2–3 times/week. The high transdermal account proposes a maximum five-week block. No shared optimal schedule follows from these reports. Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30) · Long-form nootropic user account (Personal report · Accessed 2026-09-30)

Source context — Biohackingu Dihexa mini-guide / Long-form nootropic user account: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Stacks

NSI-189	A log combines Dihexa with NSI-189 and reports mood and habit changes; it cannot separate the two compounds' effects.
Semax, Selank and racetams	The record includes Semax/Selank combinations and racetams with choline. One reply says choline worsened cognition.
Other multi-agent logs	NAD+, TAK-653 and ISRIB appear in broader cognitive stacks; Cerebrolysin is sometimes sequenced. These do not establish required companions.

Notes

Semax: Often paired with Dihexa in cognitive discussions, with Semax described as more immediate and Dihexa as slower acting. Some accounts alternate days after overstimulation; that adjustment does not establish a safe combination. [community]

Selank: Anxiety-modulation / calm clarity pair when Dihexa feels activating or irritable. [community]

Semax + Selank + Dihexa: A triple cognitive-peptide combination appears in some protocols. Replies often favor separate trials because concurrent use obscures which compound caused a change. [community]

Racetam + choline: Older LongeCity-style logs with piracetam-family agents plus choline source. [community]

Stacks do not establish required companions. NSI-189, Semax, Selank, choline and other nootropics appear in logs. The mini-guide lists favored combinations, while a reply says choline worsened cognition. Reported combinations are not interaction clearance. Dihexa and NSI-189 cycle log (Community discussion · Accessed 2026-09-30) · Biohackingu Dihexa mini-guide (Personal report · Accessed 2026-09-30)

Cerebrolysin: Sequenced in some clinic “neuro recovery” frameworks rather than same-day mega-stack. [community]

NAD+ (IV or other): Cellular-energy add-on in wellness clinic cognitive packages — confounds outcome credit. [community]

TAK-653 / ISRIB co-logs: 2025 NooTopics-style threads sometimes run Dihexa next to other experimental cognition agents — multi-agent, confounded. [community]

Source context — Long-form nootropic user account / Dihexa and NSI-189 cycle log / Biohackingu Dihexa mini-guide: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Watch for

Fatigue, sleep and irritation	Tiredness, headache, anxiety and insomnia occur alongside favorable reports. DMSO can add skin/carrier reactions.
Growth-pathway concern	Cancer-related HGF/c-Met concerns are theoretical; they are not proof of human cancer or reassurance of safety.
Evidence and product uncertainty	Retracted or questioned papers weaken mechanism claims. Animal work and unverified product labels do not establish a safe human amount or repeated-course safety.

Notes

Fatigue, headache and sleep changes. Oral tiredness, insomnia, anxiety and headache occur in the discussion alongside positive reports. DMSO adds carrier/skin-reaction questions; a bad reaction cannot automatically be blamed on the molecule alone. Dihexa two-week report (Community discussion · Accessed 2026-09-30) · Dihexa route comparison and learning habits (Community discussion · Accessed 2026-09-30)

Growth-pathway concern is theoretical. Community discussion raises cancer-related concerns about the HGF/c-Met pathway, which is involved in cell growth. That is a serious uncertainty, not proof that Dihexa causes cancer; retracted mechanism claims do not establish either safety or harm. Dihexa two-week report (Community discussion · Accessed 2026-09-30) · Retraction of the 2014 HGF/c-Met mechanism paper (Official context · Accessed 2026-09-30)

Questioned papers limit mechanism claims. The journal’s 2025 retraction and the 2021 Notice of Concern weaken the evidence behind mechanism and potency claims. Rat/cell experiments do not establish a safe human amount or repeated-course safety. Retraction of the 2014 HGF/c-Met mechanism paper (Official context · Accessed 2026-09-30) · Journal Notice of Concern: McCoy 2013 (Official context · Accessed 2026-09-30) · McCoy 2013: rat and cell work (Animal context · Accessed 2026-09-30)

Uncertainty: Without third-party testing, labeled mg, salt form, and actual Dihexa content are poorly verified; DMSO solutions add volume/measurement error. [community]

Source context — Dihexa two-week report / Dihexa route comparison and learning habits: Anonymous self-reports; unverified products, route differences, co-use and expectations can change the outcome. No prevalence, causation or human kinetics established.

Source context — Retraction of the 2014 HGF/c-Met mechanism paper: Bibliographic record, not full notice; no figure/fraud details inferred.

Source context — Journal Notice of Concern: McCoy 2013: Notice verifies integrity status, not any dosing or timing number.

Full notes

What it is and why people discuss it

An altered peptide-derived molecule. Dihexa was developed from angiotensin IV, a short signaling peptide. Online discussions often put it beside other nootropics, meaning substances people explore for thinking, memory or concentration. Animal context Community
The “new connections” story. The appeal is that it might help brain cells form connections, making learning easier. That idea comes from animal/cell work and online interpretation. A central mechanism paper was retracted, and the original characterization paper carries a Notice of Concern. Official context Official context Animal context
Oral and transdermal accounts differ. Capsules/tablets are swallowed; transdermal accounts involve delivery through skin, often with DMSO as a carrier. They are different formulations, and reported milligrams cannot establish equivalent absorption. Reddit Personal report Community

Benefits people report

Recall, learning and verbal fluency. Favorable nootropic accounts describe easier recall, connecting ideas and smoother conversations. One creator noticed better productivity and memory around week three; others describe little or no change. Personal report Personal report Reddit
Curiosity and everyday engagement. A strong transdermal account describes more interest in learning and creativity. A Dihexa/NSI-189 log describes easier habit changes and better mood, but the combination cannot isolate Dihexa. Personal report Reddit
Subtle changes without a different feeling. The two-week author reported better chess performance while feeling unchanged. Occasional other nootropics, practice and day-to-day variation remain competing explanations. Reddit

Doses people discuss

Oral charts: about 2–10 mg per day. The preserved community record contains this band and higher 10–20 mg charts. Direct oral commenters describe 4 mg and 8 mg with fatigue; the two-week author names 5 mg daily but does not explicitly state the route. Community Reddit
Intermittent reports: 5–10 mg, several times weekly or every other day. The mini-guide author reports 5 mg 2–3 times/week, route unstated. A separate stack log names 10 mg every other day with NSI-189; these are different schedules and people. Personal report Reddit
Transdermal amounts span much wider ranges. Legacy notes include about 1–5 mg. Higher accounts describe 15–30 mg every 3–5 days or 25–40 mg every 8–10 days. They do not establish a standard dose, a preparation recipe or equivalence to capsules. Community Personal report Reddit

Half-life discussed in the community

“About 12–13 days” is widely circulated lore. The stack log repeats around twelve days. Its underlying source is rat IV pharmacokinetics, not human oral or transdermal measurement. Keep the community claim visible without treating it as a human clearance clock. Reddit Community
The interpretation is disputed. The two-week thread includes both long-half-life arguments and a contrary short-elimination claim. Neither commenter measured human kinetics; feeling an effect between doses cannot settle the half-life. Reddit

When people notice it

Benefits described after days to weeks. One creator noticed changes around week three; the chess account noticed a performance difference in week two without feeling different. Some accounts instead describe early effects or nothing after repeated use. Personal report Reddit Reddit
An early symptom is not cognitive improvement. The oral 4 mg/8 mg commenter felt tired roughly two hours later. That is an adverse-response timeline, not evidence of a two-hour memory-benefit onset. Reddit

How long people say changes last

Persistence varies; no dependable one-dose window. A transdermal contributor reports effects throughout an 8–10-day interval. A separate strong account describes lasting changes that became less intense over time. Neither establishes how long another person would benefit. Reddit Personal report
Some early effects disappear. One contributor felt stimulation on the first two days, then nothing over about fifteen later uses. Persistent learning gains, ongoing stimulation and bodily drug half-life are separate questions. Reddit

Courses and breaks people describe

Two weeks on / two weeks off appears in the old discussion. The preserved record also includes longer 4–8-week blocks and multi-week breaks. These are community templates, not a validated washout or a claim that short courses eliminate risk. Community
Four weeks on / four weeks off: one creator’s pattern. The mini-guide author describes that course with 5 mg 2–3 times/week. The high transdermal account proposes a maximum five-week block. No shared optimal schedule follows from these reports. Personal report Personal report

Good to know

Fatigue, headache and sleep changes. Oral tiredness, insomnia, anxiety and headache occur in the discussion alongside positive reports. DMSO adds carrier/skin-reaction questions; a bad reaction cannot automatically be blamed on the molecule alone. Reddit Reddit Community
Growth-pathway concern is theoretical. Community discussion raises cancer-related concerns about the HGF/c-Met pathway, which is involved in cell growth. That is a serious uncertainty, not proof that Dihexa causes cancer; retracted mechanism claims do not establish either safety or harm. Community Reddit Official context
Questioned papers limit mechanism claims. The journal’s 2025 retraction and the 2021 Notice of Concern weaken the evidence behind mechanism and potency claims. Rat/cell experiments do not establish a safe human amount or repeated-course safety. Official context Official context Animal context

From community discussion

“Felt nothing” can coexist with a claimed result. The chess report is interesting because the author noticed performance, not a drug feeling. It remains a single uncontrolled experience with other nootropics, not a reliable cognitive test of Dihexa. Reddit
Route changes can change the story. Some users favor transdermal use; another describes an oral month with benefits, while others report oral fatigue or no effect. Different products and carriers prevent treating route preference as a proven comparison. Reddit Personal report Reddit
Learning habits are part of the account. One recovery story also involved medical care, other compounds, language learning and programming courses. Those activities explain why the person discusses learning alongside Dihexa; they do not prove the compound repaired an injury. Reddit
Stacks do not establish required companions. NSI-189, Semax, Selank, choline and other nootropics appear in logs. The mini-guide lists favored combinations, while a reply says choline worsened cognition. Reported combinations are not interaction clearance. Reddit Personal report Community
Whether benefits last is unclear. Strong positive stories sit beside faded first-day effects and complete nonresponse. A skill learned during a course may persist for many reasons; it does not measure new synapses or drug remaining in the body. Personal report Reddit Reddit