Phenylpiracetam Hydrazide
Fonturacetam hydrazide · PHA · 2-(2-oxo-4-phenylpyrrolidin-1-yl)acetohydrazide
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At a glance
Overview
What Phenylpiracetam Hydrazide Actually Is#
Phenylpiracetam hydrazide (PHA) is a designer analog of phenylpiracetam (fonturacetam) in which the parent's terminal amide is swapped for a hydrazide group. The molecule was first reported by a Soviet anticonvulsant screening program in 1980 and re-surfaced in the Western nootropic community around 2014, where it earned a reputation among focus-stack and cognitive-output users as a longer, sharper, more dopaminergic cousin of standard phenylpiracetam.
The appeal is practical. Subjects running 50–75mg report onset within 15–45 minutes, a clean stimulant-cognitive effect, and a subjective duration of 6–10 hours — meaningfully longer than equimolar phenylpiracetam, at roughly half the milligram dose for an equivalent or stronger response. Mechanistically the parent compound increases extracellular dopamine, noradrenaline and serotonin, upregulates NMDA and nicotinic ACh receptor density in cortex and hippocampus, and shows weak DAT affinity (Malykh & Sadaie 2010; Zvejniece et al. 2011). The hydrazide is structurally a β-aryl-GABA / racetam-class agent (Wang et al. 2023) and inherits that pharmacology by extrapolation, though no dedicated receptor screen of the hydrazide itself has been published.
"Most people report the onset is within 15–45 minutes, and the effects last longer than regular phenylpiracetam, closer to 8 hours or more." — r/Nootropics community discussion, 2022
PHA is a niche tool, not a daily driver. Tolerance builds within roughly five days of consecutive dosing, the hydrazide chemical class carries unresolved safety questions (isoniazid-style hepatotoxicity and theoretical MAO inhibition are the live concerns), and the parent compound is WADA-prohibited — anyone tested should assume the hydrazide is too. The sections below cover documented PHA dose ranges, oral vs sublingual administration, the choline + B6 support stack, tolerance and frequency management, the hydrazide-class side-effect profile, and the contraindications that matter most — particularly the SSRI/SNRI/MAOI interaction risk.
How Phenylpiracetam Hydrazide works
Phenylpiracetam hydrazide (PHA) is a designer analog of phenylpiracetam (fonturacetam) in which the terminal primary amide is replaced with a hydrazide group. It belongs structurally to the β-aryl-GABA / racetam family, and its mechanistic profile is extrapolated almost entirely from the parent compound — no dedicated receptor-binding screen of the hydrazide itself has been published in the English-language literature. What follows is what the parent-compound pharmacology predicts, with the caveat that the hydrazide modification appears to extend duration and sharpen the dopaminergic character.
"The β-aryl-GABA analogs, including phenylpiracetam hydrazide, belong to the class of CNS-active agents and are structurally related to racetams." — Wang P-L, Chan Y-X, Chang C-C., Tetrahedron (2023)
Dopaminergic Drive and DAT Interaction#
The defining feature of the parent compound — and the reason PHA "feels" like a stimulant rather than a classical racetam — is direct action on the dopamine transporter. Phenylpiracetam behaves functionally as a weak NDRI, elevating striatal dopamine and producing measurable locomotor and anti-fatigue effects in rodents. This is the basis for its inclusion on the WADA prohibited list and the mechanistic anchor for PHA's subjective "clean stimulant + focus" profile.
"Phenylpiracetam exhibited significant increases in locomotor and anti-amnesic activities, indicating dopaminergic and psychostimulant properties." — Zvejniece L, Svalbe B, Veinberg G, et al., Pharmacol Biochem Behav (2011)
Practically, this is the mechanism users feel in the first 30–45 minutes: drive, verbal fluency, willingness to start work, and tolerance to monotony. It is also the reason tolerance builds rapidly with consecutive-day administration — the same downregulation pattern seen with other dopaminergic stimulants.
Noradrenergic and Serotonergic Elevation#
Alongside dopamine, the parent compound raises extracellular noradrenaline and serotonin in cortical microdialysis studies. The noradrenergic component contributes the alertness and cardiovascular signal (mild tachycardia, appetite suppression, occasional jaw tension); the serotonergic component is the mechanistic reason combining PHA with SSRIs, SNRIs, tramadol, or MDMA is a hard avoid — the interaction risk is real even before factoring in the hydrazide-class MAO-inhibition concern below.
"Phenotropil (phenylpiracetam) increased the density of NMDA and nACh receptors in the cortex and hippocampus, and increased extracellular concentrations of dopamine, noradrenaline and serotonin in animal studies." — Malykh AG, Sadaie MR, Drugs (2010)
NMDA, AMPA, and Nicotinic Cholinergic Upregulation#
This is the racetam-class mechanism PHA inherits structurally. Chronic phenylpiracetam administration upregulates NMDA and nicotinic acetylcholine receptor density in cortex and hippocampus and modulates AMPA-mediated glutamatergic transmission. The practical correlate is the memory-consolidation and working-memory component of the effect — the part that feels like a racetam rather than a stimulant — and the reason a choline source (alpha-GPC 300mg or CDP-choline 200mg) is co-administered in standard protocols. Cholinergic turnover increases under racetam exposure; under-supplied choline produces the dull frontal headache and "racetam fog" the community reliably reports without it.
GABAergic / Anticonvulsant Activity#
PHA was first described by a Soviet research group in 1980 as part of an anticonvulsant screening series, and the original pharmacological data place it squarely in the GABAergic-modulator camp.
"ED50 against maximal electroshock seizure of phenylpiracetam hydrazide was 310 mg/kg in mice, as reported in the original Soviet pharmacological screening." — NCATS Inxight Drugs, NCATS Inxight Drugs database (2020)
That anticonvulsant signal is the mechanistic balance against the dopaminergic/noradrenergic activation — it is part of why subjective reports describe PHA as "stimulating without being jittery," and part of why the compound is poorly suited to stacking with other strong stimulants, which disrupt that balance.
Extended Duration and the Hydrazide Modification#
The functional difference between PHA and the parent compound is duration and apparent potency per milligram. Whether this reflects intrinsically longer terminal half-life of the hydrazide, slower clearance, or slow metabolic back-conversion to phenylpiracetam is unresolved in the literature.
"Most people report the onset is within 15–45 minutes, and the effects last longer than regular phenylpiracetam, closer to 8 hours or more." — r/Nootropics community, Reddit (2022)
Two practical consequences follow. First, the modal community dose is roughly half the milligram dose of the parent for an equivalent or stronger effect — 50mg PHA tracks closely to 100mg phenylpiracetam by user account. Second, the longer tail is the reason AM-only administration is non-negotiable: a 50–100mg dose taken at 2 PM reliably wrecks sleep that night.
Hydrazide-Class Considerations (MAO and B6)#
The mechanism that does not have direct data on PHA but cannot be ignored is the hydrazide functional group itself. Clinically used hydrazides — isoniazid, iproniazid, phenelzine — share a chemistry that produces monoamine oxidase inhibition and pyridoxine (B6) depletion. No MAO-A/B binding screen on PHA has been published, so the magnitude of this effect at nootropic doses is unknown. The mechanistically conservative position the community has converged on: treat PHA as if it carries some non-zero MAOI character, avoid serotonergic co-administration, and hedge with 25–50mg pyridoxine on use days. This is the single largest mechanistic unknown around the compound and the main reason it sits in a more experimental tier than its parent.
Protocol
| Level | Dose | Frequency | Notes |
|---|---|---|---|
| Low | 25–50 mg | As needed | Documented entry-level range |
| Mid | 50–100 mg | As needed | Most commonly studied range |
| High | 100–150 mg | As needed | AM-only administration — dosing after early afternoon reliably disrupts sleep given the 6–10h subjective duration. Tolerance builds rapidly with daily use; the modal community pattern is 1–2 administrations per week with non-consecutive days. |
Cycle length & outcomes
Documented cycle
1–8 weeks
Plateau after
4 wks
Cycling Phenylpiracetam Hydrazide#
PHA does not cycle in the hormonal sense — there is nothing to suppress and nothing to recover. What it does require is frequency discipline, because tolerance to the dopaminergic / stimulant component builds within days of consecutive use. The protocol that gets the most out of this compound treats it as an intermittent cognitive tool, not a daily nootropic.
Dose & Cycle Length by Goal#
| Goal | Cycle Length | Dose | Frequency |
|---|---|---|---|
| First exposure / titration | 1–2 weeks | 25–50mg AM | 1–2× per week, non-consecutive |
| Cognitive output (deadlines, study blocks) | 2–4 weeks | 50–75mg AM | 1–2× per week |
| Cut-phase training drive | 4–6 weeks | 50mg, 45–60min pre-training | 1–2× per week, hard sessions only |
| Stim-rotation slot | Open-ended | 50–100mg AM | Once per 7–10 days |
| Aggressive / experienced | ≤4 weeks | 100–150mg AM | 1× per week maximum |
The community ceiling sits at roughly 8 weeks of intermittent use before a 2–4 week washout. This isn't driven by hormonal recovery — it's driven by (a) accumulating tolerance that no longer resets within a week, and (b) the unresolved hydrazide-class hepatotoxicity question, which argues against indefinite chronic exposure even at low frequency.
Onset & Duration#
Subjective onset is 15–45 minutes orally or sublingually, with a perceived working window of 6–10 hours — meaningfully longer than the parent fonturacetam.
"Most people report the onset is within 15–45 minutes, and the effects last longer than regular phenylpiracetam, closer to 8 hours or more." — r/Nootropics community, 2022
The practical consequence: AM-only dosing is non-negotiable. Anything administered after roughly 1 PM reliably costs a night of sleep. There is no slow-build-up phase — the first dose at 50mg is approximately as effective as the tenth, which is part of why frequency rather than dose is the variable to titrate.
Loading & Tapering#
Neither is used. Racetam-class loading protocols (the old "piracetam attack dose" tradition) have no community precedent for PHA, and the rapid tolerance curve actively punishes attempts at front-loading. Tapering is equally unnecessary — discontinuation produces no withdrawal beyond a flat day or two after heavy single-session use, which reflects dopaminergic comedown rather than physical dependence.
The one structural element worth keeping is a choline co-administration throughout any active week:
- Alpha-GPC 300mg, OR
- CDP-choline 200mg
Co-administered with the PHA dose. This is standard racetam practice and meaningfully reduces the dull "racetam headache" that some users report. A pyridoxine (B6) hedge at 25–50mg on dosing days is a reasonable precaution given the isoniazid-class precedent for hydrazide B6 depletion — cheap insurance against a real but uncharacterized risk.
Tolerance Management#
The single most important protocol variable. Daily administration produces near-complete loss of subjective effect within 3–5 days — the same pattern documented for the parent compound.
"Phenylpiracetam exhibited significant increases in locomotor and anti-amnesic activities, indicating dopaminergic and psychostimulant properties." — Zvejniece et al., Pharmacol Biochem Behav, 2011
The dopaminergic mechanism is what produces the acute effect; it is also what burns out under daily exposure. The community pattern that holds the response flat indefinitely:
- Maximum 2 dosing days per week
- Non-consecutive (e.g., Monday + Thursday, not Monday + Tuesday)
- Full reset: 7–10 days off restores baseline response
- Stim-rotation: PHA slotted into a 3–4 compound rotation (caffeine, modafinil, parent phenylpiracetam) with no agent used more than once per week
Users who break this pattern report needing to escalate from 50mg to 150mg within a fortnight to chase the original effect — at which point comedown severity overtakes the cognitive benefit.
Bloodwork Cadence#
No formal protocol exists. PHA is not hormonal, not hepatotoxic by any direct evidence, and not characterized well enough to know what to monitor specifically. That said, for anyone running it beyond occasional one-off use, a yearly liver panel (ALT, AST, GGT) is sensible given the hydrazide structural class — isoniazid, iproniazid, and phenelzine all carry hepatotoxicity signals, and the absence of data on PHA itself argues for caution rather than complacency. Baseline before initiating regular use, retest at 6–12 months if administration continues.
No other bloodwork is mechanistically indicated.
When to Pull the Plug#
End the cycle — or extend the washout — if any of the following appear:
- Subjective effect has dropped to baseline at the working dose and tolerance hasn't reset within 10 days off
- Sleep disruption is persisting on non-dosing days
- Comedown days are eating more productive time than dosing days are creating
- Any GI, hepatic, or peripheral neurological symptoms (numbness, tingling) appear during a use period
A 2–4 week complete washout resolves the first three. The fourth is a hard stop pending bloodwork.
Run intermittently, kept to AM, paired with choline, and capped at 1–2 sessions per week, PHA holds its response window indefinitely and stays well inside what the small available evidence base suggests is a manageable profile.
Risks & mistakes
Common (most users)#
- Insomnia — the dominant complaint and the easiest to fix. The subjective duration runs 6–10h, so any dose administered after roughly 1 PM reliably wrecks sleep. AM-only dosing eliminates this entirely.
- Jaw tension / mild bruxism — classic dopaminergic-stimulant signature. Drops with dose reduction; usually a signal that 100mg+ was overshooting.
- Appetite suppression — useful during a cut, inconvenient on a lean-bulk. Front-load calories before the dose lands, since the appetite hit is strongest during the 2–6h peak window.
- Headache / "racetam fog" — the standard racetam-class complaint. Mitigated by co-administration of alpha-GPC 300mg or CDP-choline 200mg with the dose.
- Mild tachycardia and elevated resting HR — proportional to dose. Stacking with high-dose caffeine, yohimbine, or amphetamine-class stimulants amplifies this disproportionately; the protocol calls for moderate caffeine at most.
- Irritability / "stim edge" — typically a sign the dose is too high for the individual. Dropping from 100mg to 50–75mg generally cleans this up without losing the cognitive effect.
"Most people report the onset is within 15–45 minutes, and the effects last longer than regular phenylpiracetam, closer to 8 hours or more." — r/Nootropics community discussion (2022)
Uncommon (dose-dependent or individual)#
- Next-day comedown — flat mood, mental fatigue, and dulled motivation the day after a heavy session. More pronounced than with the parent compound and the single best argument for keeping doses at 50–75mg rather than chasing 150mg. L-tyrosine 500–1000mg pre-dose appears to soften the catecholamine debt.
- Rapid tolerance collapse — daily administration burns the subjective effect within 3–5 days, mirroring the parent fonturacetam. The fix is structural: 1–2 doses per week, non-consecutive, with at least one weekly rotation gap. Tolerance recovers fully within ~7 days off.
- Blood-pressure elevation — expected given the dopaminergic/noradrenergic profile of the parent compound, where extracellular NA and DA are reliably increased in animal work (Malykh & Sadaie 2010). Users with cycle-related hypertension or those running AAS with elevated baseline BP should check cuff pressure on a dose day before normalizing the protocol.
- GI upset on oral administration — hydrazides are chemically reactive in gastric acid, and a minority of users report nausea on oral dosing that resolves entirely on sublingual administration (50mg held SL for 2–3 minutes).
- Anxiety / overstimulation — almost always a dose-too-high signal in stimulant-sensitive subjects. The 25mg starting dose exists for this reason; the community consistently flags 100mg out of the gate as a poor opening move.
Rare but serious#
- Hepatotoxicity (theoretical, class-based concern) — the clinically used hydrazide drugs (isoniazid, iproniazid, phenelzine) are notorious for liver toxicity, and no formal toxicology data exists on PHA itself. This is the single largest unknown around the molecule. Users running it more than occasionally are advised to check ALT, AST, and GGT yearly. Warning signs warranting immediate cessation: right-upper-quadrant pain, dark urine, jaundice, persistent nausea.
- Peripheral neuropathy / B6 depletion (theoretical) — isoniazid depletes pyridoxine and causes neuropathy at clinical doses. Whether PHA shares this liability is unknown. Pyridoxine 25–50mg on dose days is a cheap hedge. Tingling, numbness, or burning in the extremities is a stop signal.
- Serotonin syndrome / hypertensive crisis on serotonergic combinations — hydrazides as a chemical class can inhibit MAO. Until anyone publishes actual MAO-A/B binding data on this specific molecule, the cautious assumption is that some MAOI activity exists. Symptoms — hyperthermia, agitation, clonus, severe hypertension — warrant immediate medical attention.
- Seizure threshold effects — the parent's anticonvulsant signal and PHA's reported MES ED₅₀ of 310 mg/kg in mice (NCATS Inxight Drugs) suggest a net anticonvulsant character, but the data are sparse. Subjects with a seizure history or on threshold-lowering polypharmacy (bupropion, tramadol, high-dose stimulants) should treat the interaction profile as undefined.
Hard contraindications#
- MAOIs (phenelzine, tranylcypromine, selegiline, moclobemide) — do not stack. Theoretical MAOI character of the hydrazide group plus established MAOI is the textbook setup for hypertensive crisis.
- SSRIs, SNRIs, tramadol, dextromethorphan, MDMA, or other serotonergics — serotonin syndrome risk, mechanistically plausible and not worth testing.
- Pre-existing liver disease — given the hydrazide-class hepatotoxicity precedent and absence of formal toxicology data, this is a no-go.
- Pregnancy and lactation — no safety data, hydrazide-class teratogenicity signal in related drugs. Hard no.
- Competitive drug-tested athletics — the parent phenylpiracetam is WADA-prohibited in and out of competition. PHA is not separately listed but will almost certainly be flagged either as parent or via metabolism. Treat as banned.
- Stacking with amphetamines, methylphenidate, or high-dose modafinil — additive cardiovascular and dopaminergic load with no upside. Reported as unpleasant, not synergistic.
Gender, hormonal, and PCT considerations#
PHA is non-hormonal. There is no androgenic, estrogenic, or HPTA-suppressive activity, no virilization risk, and the same dose ranges apply across subjects regardless of bodyweight or sex. PCT is not required and is not applicable. Pregnancy and lactation remain hard contraindications on toxicology grounds, not hormonal ones. For users stacking PHA into a broader physique protocol — AAS cycle, GH/peptide stack, cut-phase stimulant rotation — the relevant interactions are cardiovascular (BP on cycle) and hepatic (concurrent oral 17α-alkylated AAS would compound the unknown liver question and is best avoided in the same week as PHA dosing).
FAQ — Phenylpiracetam Hydrazide
Research & citations
5 studies cited on this page.
Conclusion
Phenylpiracetam hydrazide is a potent, research-only nootropic that builds on the dopaminergic and psychostimulant profile of its parent, with a longer active window and a stronger subjective effect per milligram. Its place in the nootropic arsenal is clear: fast-onset, high-output focus for demanding cognitive days, intermittent use to avoid rapid tolerance, and a stacking foundation of choline support to blunt classic racetam headaches.
Key takeaways:
- Typical dose: 25–100 mg, administered orally or sublingually, AM only
- Subjective duration is 6–10 hours; dosing after ~1 PM reliably impairs sleep
- Tolerance builds quickly — 1–2 administrations per week is typical protocol
- A choline source (alpha-GPC 300 mg or CDP-choline 200 mg) is standard for mitigation of headache/fog
- Best stacked with moderate caffeine on heavy output days; avoid combining with MAOIs, SSRIs, SNRIs, or other serotonergics
- Hydrazide-class toxicology is an unknown; pyridoxine (B6 25–50 mg) is a community precaution during use periods
For research focused on acute cognitive drive, stimulant-like energy, and anti-fatigue effects, phenylpiracetam hydrazide commands respect as a tool best deployed in well-structured, intermittent protocols.