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EmergingResearch compoundLimited evidence

Conessine

Plant steroidal alkaloid, a potent histamine H3 receptor antagonist with a wakefulness-promoting profile.

NootropicStimulantStimulantHistaminenoo.affects.histamineDopamineAcetylcholineNorepinephrine

Pharmacology

ClassStimulant · Histamine
Primary targetHistamine H3 receptor antagonist / inverse agonist
Targets3 receptor targets
Half-lifeNot well characterized in humans; the compound is highly lipophilic and penetrates the brain well (a validated serum LC-MS/MS method exists)
OnsetNo standardized human data; in animal studies the wakefulness-promoting effect appears rapidly
EvidenceLimited evidence
Affected systemsnoo.affects.histamineDopamineAcetylcholineNorepinephrine

Contents

WHAT IS CONESSINE?

Detailed overview

Conessine is a steroidal alkaloid extracted from the bark and seeds of Holarrhena antidysenterica, a tropical shrub in the dogbane family long used in traditional medicine as an anti-dysenteric and anti-amoebic agent. Modern pharmacology rediscovered it as a potent, brain-penetrant histamine H3 receptor antagonist and inverse agonist; several medicinal-chemistry groups (Abbott, Santora and colleagues) used the natural conessine scaffold as a starting point for designing new H3 ligands. Blocking the H3 receptor releases the feedback brake on the release of histamine, acetylcholine, dopamine and norepinephrine, so it raises wakefulness and attention. It has never been tested as a cognitive enhancer in humans, so as a nootropic it is an experimental substance.

Mechanism

Histamine H3 antagonist / inverse agonist

Origin

Holarrhena antidysenterica steroidal alkaloid

Evidence

Preclinical (no human nootropic data)

Receptor profile

  • Histamine H3 receptorStrong
  • Alpha-adrenergic receptorsModerate
  • Acetylcholine / dopamine / norepinephrine release (indirect)Moderate

Safety

Side effects, stop signs, contraindications

Side effects · 5

  • No human nootropic safety data: the compound has not been tested as a cognitive enhancer in humans; effects derive from preclinical and pharmacological studies
  • Insomnia or disrupted sleep with late dosing, since it is stimulating and wakefulness-promoting
  • Possible rise in blood pressure and heart rate from the alpha-adrenergic and monoamine-releasing activity
  • Restlessness, anxiety or tremor from the enhanced histaminergic and catecholaminergic signaling
  • Unknown long-term safety; Holarrhena alkaloids carry gastrointestinal irritation potential at higher doses

Contraindications · 5

  • Pregnancy and breastfeeding: safety not established, avoid
  • Cardiovascular disease, arrhythmia or uncontrolled hypertension
  • Anxiety disorders, panic disorder: the stimulant effect may worsen them
  • Avoid combining with other stimulants or wakefulness agents due to additive effects
  • Not an approved medicine; experimental research chemical, not recommended without clinical supervision

Related Nootropics

Same therapeutic category

Studies

Related research and clinical findings

FAQ

FAQ

Plant steroidal alkaloid, a potent histamine H3 receptor antagonist with a wakefulness-promoting profile.

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Structure & chemistry

TypeNootropic
FormulaC24H40N2
UpdatedJuly 10, 2026
MolekulaX Editorial Team·Source-verified · PubMed · FDA · EMA
Updated: July 10, 2026

The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.