L THP
What do these badges mean?
Evidence tier
- AHuman-validated — Human trials showing positive results and good safety.
- BAnimal-grade — No human trials yet, but solid animal/preclinical evidence of effect and safety.
- CAnecdotal — No human or animal trials — only anecdotal/observational reports.
- DInsufficient evidence — No or insufficient evidence (encyclopedia only — never recommended by the builder).
Safety light
- 🟢 Green — Only mild, manageable side effects; reasonable safety data.
- 🟡 Yellow — Needs active management, has a meaningful contraindication/interaction, or has thin long-term data.
- 🔴 Red — Risk of a hospital-level event — treat with serious caution.
Browse-only — not on the protocol builder's curated shortlist, so the builder won't recommend it.
What is it?
Levo-tetrahydropalmatine (L-THP) is a natural alkaloid from plants in the Corydalis genus, used in Chinese medicine for centuries and systematized into modern pharmaceutical use as Rotundine — an actual prescription compound in China with a 40+ year clinical history for sleep and anxiety, not a folk supplement. That clinical history is what gives it a real-world safety record before the Western research literature even began engaging with it.
The compound belongs to the class of isoquinoline alkaloids — the same chemical family as berberine (metabolic health) and morphine (though L-THP’s pharmacological profile is radically different from opioids: it has no opioid receptor activity and no abuse potential). Its receptor profile is its distinguishing feature: triple-pathway action across the dopamine, serotonin, and norepinephrine systems, with the specific constellation of effects that makes it uniquely suited to the stimulant-clearance problem.
What does it do in my body?
The sleep disruption L-THP targets has a specific cause: stimulants elevate dopamine and norepinephrine, and that receptor activation outlasts the subjective effect of the stimulant. Long after the caffeine or pre-workout energy has worn off, the underlying receptor signaling is still running. Dopamine drives motivation and pursuit behavior. Norepinephrine drives alertness and readiness to act. Both stay elevated. The body is exhausted; the brain’s receptor systems think it’s still time to be active. That’s the wired-but-tired state.
GABA-based sedatives address this by activating the inhibitory neurotransmitter hard enough to shout the excitatory signaling down — sleep happens, but the underlying dopamine and norepinephrine elevation is still running through the night. Part of why GABA-sedated sleep and alcohol sleep feel qualitatively worse than natural sleep even when the hours look the same on paper.
L-THP works from the opposite direction. It directly quiets the receptor systems the stimulants were activating:
Dopamine antagonism (D1, D2, D3 receptors) [ESTABLISHED — Wang & Mantsch 2012, PMID 22300097]
The core mechanism. L-THP blocks dopamine receptors across D1, D2, and D3 subtypes. This is also the mechanism that makes it useful in addiction research: the same dopamine-receptor dampening that reduces compulsive drug-seeking in cocaine and methamphetamine users quietly dissolves the residual dopaminergic activation from a day of caffeine and pre-workout, just at a far less dramatic intensity. The addiction research is the proof of concept; the stimulant-clearance application is the same mechanism at the milder end of the spectrum.
Serotonin 5-HT1A receptor agonism [Wang & Mantsch 2012 review, PMID 22300097; related alkaloid THPB mechanistic confirmation: Mi et al. 2017, PMID 28085967]
The 5-HT1A receptor is the same target buspirone (the anxiety medication) works through. Activating it produces calm without sedation — racing thoughts slow, cognitive over-engagement eases, and the mental layer of the wired state quiets independently of the GABAergic pathway. This is distinct from SSRIs (which flood the synapse across all serotonin subtypes) and from benzodiazepines (which don’t touch the serotonin system). It’s a specific anxiety-quieting receptor, and it accounts for the “mind slows down” component of L-THP’s effect profile.
Alpha-adrenergic modulation [Wang & Mantsch 2012, PMID 22300097]
L-THP also acts at alpha-adrenergic receptors, reducing sympathetic nervous-system tone. Effect: heart rate settles, breathing deepens, autonomic balance shifts toward parasympathetic dominance. This directly addresses the physiological arousal component — particularly relevant for post-training catecholamine elevation even in the absence of exogenous stimulants.
The pharmacological MRI confirmation: A 2012 neuroimaging study in rats used 9.4 Tesla MRI to track L-THP’s effects across brain systems. The finding: L-THP “selectively activated the key brain regions of the dopaminergic, serotonergic and noradrenergic systems in a dose-dependent manner” — confirming the triple-system engagement is a real, imaging-detectable neurological effect, not a theoretical pharmacology claim.
How can it help me?
- Where the science stands: Phase 1 clinical trial in cocaine users · rodent self-administration and neuroimaging data ·
[REVIEW]comprehensive pharmacology review
The full evidence — every human, animal, and lab study, graded — is one tap away: use the See the deeper science → toggle at the top.
Is it dangerous? What are the side effects?
Regulatory status: L-THP is:
- China: Prescription pharmaceutical compound (Rotundine) — long-standing clinical use in sleep and anxiety
- United States: Available as a dietary supplement (OTC); not FDA-approved for any indication
- WADA: No known prohibition (no performance-enhancing mechanism; dopamine antagonism is not a WADA concern)
Typical dosing
Talk to your medical provider before starting any protocol. That said, here are the doses most people commonly use — shared for educational purposes so you can have an informed conversation. These peptides are sold for research use only and are not FDA-approved drugs, and this isn't medical advice.
Chinese clinical dose range (Rotundine prescription use): 60–240 mg for sleep and anxiety.
Timing: Take 30–60 minutes before intended sleep. Peak effect 30–60 minutes post-dose; duration 4–6 hours.
Frequency: Chinese clinical use allows nightly. Some researchers prefer 3–4 nights per week to preserve natural sleep-drive sensitivity on off nights.
Dose titration: Individual response varies significantly. Starting at the lower end of the Chinese clinical range (~60–100 mg) and titrating by response is the sensible approach. Higher doses produce more sedation and more residual next-morning effect.
The “subtle effect” note: Because L-THP doesn’t produce a “high” or dramatic hit-by-a-truck sedation, some users don’t consciously notice it working at first. The effects tend to show up in objective sleep metrics (sleep tracker data, HRV, time to sleep onset) and next-day alertness rather than in the moment of taking it. Give it 3–5 nights to establish a clear picture.
What should I avoid combining — and what's synergistic?
What to pair it with (non-GABAergic sleep adjuncts that complement without duplicating the pathway):
- Glycine (3–5 g) — lowers core body temperature via peripheral vasodilation, which is a direct sleep-onset signal
- Magnesium glycinate or L-threonate — NMDA modulation, muscle relaxation; additive to L-THP without pathway overlap
- Apigenin (50 mg) — mild partial benzodiazepine-receptor agonist at doses found in chamomile; low-level GABA activity that doesn’t hit the dangerous-combination threshold
- Taurine — glycine receptor agonism, lightly anxiolytic, compatible
What NOT to pair it with (the hard rule): Alcohol, benzodiazepines, opioids, phenibut, kava, or any GABAergic sedative. The combined sedation of dopaminergic quieting (L-THP) plus GABAergic suppression can be significant and dangerous at higher doses. This is the one non-negotiable safety constraint for L-THP.
How can I buy this?
We don't have a verified affiliate source for L THP yet, so there's no coupon or vendor link here — we won't point you to a seller we haven't vetted. When buying any research-use-only peptide, the single biggest variable is the supply chain: insist on a vendor that publishes third-party Certificates of Analysis (COAs) confirming identity and >99% purity. Working with a peptide-literate clinician is one solid route — see our provider directory — or check back as our verified sources list grows.
L-THP is the most mechanistically novel sleep compound available to the research-minded user. While everything else in the sleep space sedates over the top of an activated brain, L-THP turns down the specific receptor systems that stimulants activate in the first place. The result is sleep that arrives because the neurochemical reason for wakefulness has been addressed — not because something forced the brain offline. Forty years of Chinese clinical use and a human Phase 1 trial confirm the safety profile. The human trial data in stimulant users is what most sleep compounds lack entirely.
| Class | Natural plant alkaloid (Corydalis species); NOT a peptide |
| Chinese pharmaceutical name | Rotundine; 40+ years of Chinese prescription use for sleep and anxiety |
| Mechanism (one line) | Triple-pathway: D1/D2/D3 dopamine receptor antagonism + 5-HT1A serotonin receptor agonism + alpha-adrenergic modulation — dampens the neurochemical residue stimulants leave elevated |
| Route | Oral |
| Duration | Peak effect ~30–60 min post-administration; lasts 4–6 hours |
| Evidence base | Phase 1 clinical trial in cocaine users · rodent self-administration and neuroimaging data · [REVIEW] comprehensive pharmacology review |
| Regulatory status | Not FDA-approved; available as a supplement (OTC in the US); prescription compound in China (Rotundine) |
| Primary use case in OHM protocols | Sleep quality restoration for stimulant-loaded users; GH-axis peptide protocol adjunct; post-training recovery |
| OHM vendor | None currently — not in Alyve, US Pure Peptides, or BioLongevity Labs catalogs |
Why this belongs in a peptide protocol
L-THP is not a peptide. It’s a natural alkaloid extracted from Corydalis plants — and it’s in the OHM peptide KB for one reason: sleep quality is a direct input to GH-axis peptide outcomes.
Growth hormone is secreted in pulses during deep sleep. Every GH-secretagogue protocol — Ipamorelin, CJC-1295, Sermorelin, Tesamorelin — depends on that deep-sleep architecture for its primary output. A protocol run on caffeine-compressed, stimulant-loaded sleep is running at a fraction of its potential. The pulse happens; if the deep-sleep architecture is compromised, the pulse is smaller, the timing is off, and the therapeutic benefit is cut.
The typical OHM reader running a GH-axis peptide is also likely consuming caffeine, pre-workout, or other stimulants throughout the day. That’s the intersection L-THP addresses: a compound that directly clears the neurochemical residue those stimulants leave behind — restoring the sleep quality the peptide protocol requires.
It also fits anyone running MOTS-c or metabolic peptides in the context of heavy daily stimulant use, where the wired-but-tired state disrupts both recovery and the mitochondrial adaptation the peptide is trying to drive.
What it is
Levo-tetrahydropalmatine (L-THP) is a natural alkaloid from plants in the Corydalis genus, used in Chinese medicine for centuries and systematized into modern pharmaceutical use as Rotundine — an actual prescription compound in China with a 40+ year clinical history for sleep and anxiety, not a folk supplement. That clinical history is what gives it a real-world safety record before the Western research literature even began engaging with it.
The compound belongs to the class of isoquinoline alkaloids — the same chemical family as berberine (metabolic health) and morphine (though L-THP’s pharmacological profile is radically different from opioids: it has no opioid receptor activity and no abuse potential). Its receptor profile is its distinguishing feature: triple-pathway action across the dopamine, serotonin, and norepinephrine systems, with the specific constellation of effects that makes it uniquely suited to the stimulant-clearance problem.
How it works
The sleep disruption L-THP targets has a specific cause: stimulants elevate dopamine and norepinephrine, and that receptor activation outlasts the subjective effect of the stimulant. Long after the caffeine or pre-workout energy has worn off, the underlying receptor signaling is still running. Dopamine drives motivation and pursuit behavior. Norepinephrine drives alertness and readiness to act. Both stay elevated. The body is exhausted; the brain’s receptor systems think it’s still time to be active. That’s the wired-but-tired state.
GABA-based sedatives address this by activating the inhibitory neurotransmitter hard enough to shout the excitatory signaling down — sleep happens, but the underlying dopamine and norepinephrine elevation is still running through the night. Part of why GABA-sedated sleep and alcohol sleep feel qualitatively worse than natural sleep even when the hours look the same on paper.
L-THP works from the opposite direction. It directly quiets the receptor systems the stimulants were activating:
Dopamine antagonism (D1, D2, D3 receptors) [ESTABLISHED — Wang & Mantsch 2012, PMID 22300097]
The core mechanism. L-THP blocks dopamine receptors across D1, D2, and D3 subtypes. This is also the mechanism that makes it useful in addiction research: the same dopamine-receptor dampening that reduces compulsive drug-seeking in cocaine and methamphetamine users quietly dissolves the residual dopaminergic activation from a day of caffeine and pre-workout, just at a far less dramatic intensity. The addiction research is the proof of concept; the stimulant-clearance application is the same mechanism at the milder end of the spectrum.
Serotonin 5-HT1A receptor agonism [Wang & Mantsch 2012 review, PMID 22300097; related alkaloid THPB mechanistic confirmation: Mi et al. 2017, PMID 28085967]
The 5-HT1A receptor is the same target buspirone (the anxiety medication) works through. Activating it produces calm without sedation — racing thoughts slow, cognitive over-engagement eases, and the mental layer of the wired state quiets independently of the GABAergic pathway. This is distinct from SSRIs (which flood the synapse across all serotonin subtypes) and from benzodiazepines (which don’t touch the serotonin system). It’s a specific anxiety-quieting receptor, and it accounts for the “mind slows down” component of L-THP’s effect profile.
Alpha-adrenergic modulation [Wang & Mantsch 2012, PMID 22300097]
L-THP also acts at alpha-adrenergic receptors, reducing sympathetic nervous-system tone. Effect: heart rate settles, breathing deepens, autonomic balance shifts toward parasympathetic dominance. This directly addresses the physiological arousal component — particularly relevant for post-training catecholamine elevation even in the absence of exogenous stimulants.
The pharmacological MRI confirmation: A 2012 neuroimaging study in rats used 9.4 Tesla MRI to track L-THP’s effects across brain systems. The finding: L-THP “selectively activated the key brain regions of the dopaminergic, serotonergic and noradrenergic systems in a dose-dependent manner” — confirming the triple-system engagement is a real, imaging-detectable neurological effect, not a theoretical pharmacology claim.
What the research shows
** The Phase 1 clinical trial in cocaine users.** Hassan HE et al. J Clin Pharmacol. 2017;57(2):151-160. PMID 27363313.
A randomized, double-blind, placebo-controlled Phase 1 trial. L-THP was safe, well-tolerated, and did not interact dangerously with cocaine. This is the cleanest piece of clinical data on L-THP in a Western regulatory context. Two things it establishes: (1) human safety in a formal controlled trial, and (2) the compound can be administered alongside active stimulant signaling without producing a dangerous interaction. The stimulant-clearance inference is mechanism-based extrapolation — the trial wasn’t specifically testing L-THP as a sleep aid in caffeine users — but the pharmacological foundation is human-trial anchored.
** Dopamine-antagonism reduces stimulant-seeking.** Gong X et al. “Levo-tetrahydropalmatine, a natural, mixed dopamine receptor antagonist, inhibits methamphetamine self-administration and methamphetamine-induced reinstatement.” Pharmacol Biochem Behav. 2016;144:67-72. PMID 26806555.
Rat model. L-THP at 2.5–5 mg/kg reduced methamphetamine self-administration and blocked reinstatement of drug-seeking after abstinence, with no motor impairment at effective doses. The addiction research context is more extreme than caffeine, which makes it useful as a proof of concept: if L-THP is effective enough to reduce compulsive methamphetamine seeking in animal models, the same mechanism clearly has capacity to quiet residual dopamine signaling from daily caffeine and pre-workout use.
** Nicotine self-administration.** Faison SL et al. BMC Pharmacol Toxicol. 2016;17(1):49. PMID 27817750.
L-THP reduces nicotine self-administration and reinstatement in rats — extending the receptor-level mechanism to a third stimulant category relevant to OHM readers.
**** Liu X et al. Magn Reson Imaging. 2012. PMID 22079072. Summarized above.
[REVIEW] Wang JB, Mantsch JR. Future Med Chem. 2012;4(2):177-186. PMID 22300097. The foundational Western pharmacology review. Confirms the receptor profile, reviews preclinical evidence, and covers 40 years of Chinese clinical history and safety record.
What the evidence doesn’t have (honest gap): No dedicated clinical trial testing L-THP specifically as a sleep-quality tool for stimulant users. The mechanism is confirmed, the pharmacology is anchored, the human safety data is clean — but the direct stimulant-clearance-to-sleep-improvement RCT doesn’t exist yet. The inference is well-grounded; it’s not closed by a dedicated trial.
Real-world protocol
The doses and schedules here are for educational and informational purposes only. This is not FDA-approved for any indication and is sold over-the-counter in the US. This is not medical advice. Consult a qualified physician before beginning any protocol.
Chinese clinical dose range (Rotundine prescription use): 60–240 mg for sleep and anxiety.
Timing: Take 30–60 minutes before intended sleep. Peak effect 30–60 minutes post-dose; duration 4–6 hours.
What to pair it with (non-GABAergic sleep adjuncts that complement without duplicating the pathway):
- Glycine (3–5 g) — lowers core body temperature via peripheral vasodilation, which is a direct sleep-onset signal
- Magnesium glycinate or L-threonate — NMDA modulation, muscle relaxation; additive to L-THP without pathway overlap
- Apigenin (50 mg) — mild partial benzodiazepine-receptor agonist at doses found in chamomile; low-level GABA activity that doesn’t hit the dangerous-combination threshold
- Taurine — glycine receptor agonism, lightly anxiolytic, compatible
What NOT to pair it with (the hard rule): Alcohol, benzodiazepines, opioids, phenibut, kava, or any GABAergic sedative. The combined sedation of dopaminergic quieting (L-THP) plus GABAergic suppression can be significant and dangerous at higher doses. This is the one non-negotiable safety constraint for L-THP.
Frequency: Chinese clinical use allows nightly. Some researchers prefer 3–4 nights per week to preserve natural sleep-drive sensitivity on off nights.
Dose titration: Individual response varies significantly. Starting at the lower end of the Chinese clinical range (~60–100 mg) and titrating by response is the sensible approach. Higher doses produce more sedation and more residual next-morning effect.
The “subtle effect” note: Because L-THP doesn’t produce a “high” or dramatic hit-by-a-truck sedation, some users don’t consciously notice it working at first. The effects tend to show up in objective sleep metrics (sleep tracker data, HRV, time to sleep onset) and next-day alertness rather than in the moment of taking it. Give it 3–5 nights to establish a clear picture.
The GH-axis connection — why this belongs in every GH-axis stack
GH-secretagogues like Ipamorelin and CJC-1295 work by amplifying the GH pulse the pituitary sends out during deep sleep. The amplitude of that pulse — and therefore the clinical benefit of the peptide protocol — is directly gated by the quality of that sleep.
A common pattern in the OHM audience: heavy daily stimulant load (pre-workout, caffeine, nicotine) → elevated dopamine/norepinephrine → compressed deep sleep → reduced GH pulse amplitude → suboptimal GH peptide outcomes. The peptide is working; the sleep architecture is cutting the yield.
L-THP addresses this at the root: quieting the residual stimulant signaling that was degrading the sleep architecture in the first place. The downstream effect is better deep sleep → bigger GH pulse → better GH-axis peptide outcomes. The compound isn’t a direct GH-axis modulator; it’s the sleep-quality lever that determines how much of the peptide protocol actually converts to physiological effect.
The long-term secondary observation: consistent L-THP use and improved sleep quality tends to reduce the next-morning stimulant demand, as natural alertness improves. Reduced stimulant intake further improves the next night’s sleep quality. A restorative cycle rather than a compensatory one.
Side effects & safety
The established safety profile is clean. Forty years of Chinese clinical use as Rotundine without documented abuse potential. Phase 1 RCT in cocaine users (PMID 27363313) confirming safety alongside stimulant use. No documented withdrawal syndrome. No documented abuse-potential signal — the dopamine-antagonism mechanism means it reduces, rather than activates, the reward pathway.
Contraindications:
- Pregnancy / nursing — standard caution; no safety data
- Parkinson’s disease or dopamine-related movement disorders — dopamine antagonism is directly contraindicated in conditions where dopamine is already depleted or signaling is already disrupted
- Concurrent antipsychotic medications — additive dopamine antagonism; not to be combined without clinician oversight
The theoretical long-term concern: Strong chronic dopamine antagonism (at antipsychotic doses) is associated with tardive dyskinesia and related movement effects. L-THP is a milder, partial modulator in this receptor class, and no movement side effects have appeared in 40 years of Chinese clinical use. The concern warrants awareness for anyone considering long-term daily use at higher doses — it’s not a documented risk, it’s a receptor-class awareness note.
Sedation: L-THP is a sedative. Unsafe for driving or operating equipment after administration. Bedtime only.
How it compares to the GABA-sedative alternatives
| Compound | Mechanism | Stimulant residue | Tolerance | Rebound anxiety | Abuse potential |
|---|---|---|---|---|---|
| L-THP | Dopamine antagonism + 5-HT1A + alpha-adrenergic | Directly addressed | Minimal | None documented | None documented |
| Benzodiazepines | GABA-A potentiation | Overridden (still running) | Rapid (days–weeks) | Classic rebound | Significant |
| Phenibut | GABA-B agonism + some dopamine | Overridden | Rapid | Classic rebound | Significant |
| Alcohol | GABA-A + general CNS depression | Overridden | Develops over time | Common | Significant |
| Glycine + magnesium | Thermoregulation / NMDA | Not specifically addressed | None | None | None |
The honest comparison: glycine and magnesium are excellent and have zero concern profile, but they don’t address the dopaminergic component that stimulants specifically elevate. They’re foundational sleep hygiene compounds. L-THP is the specific tool for the wired-but-tired state.
Regulatory status
L-THP is:
- China: Prescription pharmaceutical compound (Rotundine) — long-standing clinical use in sleep and anxiety
- United States: Available as a dietary supplement (OTC); not FDA-approved for any indication
- WADA: No known prohibition (no performance-enhancing mechanism; dopamine antagonism is not a WADA concern)
Commercial layer
No OHM vendor currently carries L-THP. It is not in the Alyve, US Pure Peptides, or BioLongevity Labs catalogs. Available OTC from supplement vendors (Nootropics Depot, Double Wood, etc.) — none of which are OHM affiliate partners at this time.
[FUTURE-MONETIZATION — L-THP is a high-value adjunct SKU for any supplement affiliate program Rick establishes. The content hook (GH-axis sleep optimization + stimulant-clearance) is highly specific, underserved by current sleep content, and maps directly to the GH-peptide customer.]
Sources
- : 22300097 — Wang JB, Mantsch JR. 2012, Future Med Chem 4(2):177-186 — foundational pharmacology review; receptor profile: D1/D2/D3 antagonism + alpha-adrenergic + serotonin; 40-year Chinese clinical history.
- : 27363313 — Hassan HE et al. 2017, J Clin Pharmacol 57(2):151-160 — Phase 1 RCT in cocaine users; safe, well-tolerated, no dangerous interaction with stimulants.
- : 26806555 — Gong X et al. 2016, Pharmacol Biochem Behav 144:67-72 — meth self-administration reduction in rats; dopamine antagonism mechanism confirmed in stimulant context.
- : 27817750 — Faison SL et al. 2016, BMC Pharmacol Toxicol 17(1):49 — nicotine self-administration reduction in rats.
- : 22079072 — Liu X et al. 2012, Magn Reson Imaging — neuroimaging confirmation of dopaminergic/serotonergic/noradrenergic triple-system engagement at 9.4T.
- : 28085967 — Mi G et al. 2017, PLoS One — THPB (related Corydalis alkaloid) 5-HT1A anxiolytic mechanism confirmed; supports the serotonin-receptor arm of L-THP’s profile.
- — Derek/MPMD Substack 2026-07-14, full article digest with citation verification pass.
Related: Ipamorelin · CJC-1295 · Sermorelin · Tesamorelin · MOTS-c · NAD+.
Sources & references
- : 22300097 — Wang JB, Mantsch JR. 2012, Future Med Chem 4(2):177-186 — foundational pharmacology review; receptor profile: D1/D2/D3 antagonism + alpha-adrenergic + serotonin; 40-year Chinese clinical history.
- : 27363313 — Hassan HE et al. 2017, J Clin Pharmacol 57(2):151-160 — Phase 1 RCT in cocaine users; safe, well-tolerated, no dangerous interaction with stimulants.
- : 26806555 — Gong X et al. 2016, Pharmacol Biochem Behav 144:67-72 — meth self-administration reduction in rats; dopamine antagonism mechanism confirmed in stimulant context.
- : 27817750 — Faison SL et al. 2016, BMC Pharmacol Toxicol 17(1):49 — nicotine self-administration reduction in rats.
- : 22079072 — Liu X et al. 2012, Magn Reson Imaging — neuroimaging confirmation of dopaminergic/serotonergic/noradrenergic triple-system engagement at 9.4T.
- : 28085967 — Mi G et al. 2017, PLoS One — THPB (related Corydalis alkaloid) 5-HT1A anxiolytic mechanism confirmed; supports the serotonin-receptor arm of L-THP’s profile.
- — Derek/MPMD Substack 2026-07-14, full article digest with citation verification pass.
Related: Ipamorelin · CJC-1295 · Sermorelin · Tesamorelin · MOTS-c · NAD+.