A long-known cactus psychedelic, used ceremonially for thousands of years and central to early consciousness research before falling out of study. Early reports suggest improved mood and well-being and possible help with heavy drinking and smoking, but solid evidence is thin. Main downsides: raised blood pressure, frequent nausea, and frightening reactions. Understudied rather than disproven. (Full Review)

Protocol

Research dosing reference

300–500 mg oral

Studied across ~100–800 mg; 300–500 mg used as a representative full dose. 800 mg produced substantial adverse effects.

Best time of day

Morning

Given the 8–12 hour duration, dosed in the morning so effects subside before night.

Single vs. split dosing

Single oral dose

Taken as a single dose, not split; booster dosing is not standard and would extend an already long duration.

Time to effect

Onset

~1–2 hours

After oral intake; often longer with whole-cactus preparations.

Build to peak

2–4 hours

Effects build over the first 2–4 hours after onset.

Full duration

8–12 hours

Plasma half-life on the order of 6 hours; plan for a full day.

Benefits

Medium: Acute improvement in mood and well-being

Low: Reduction in depressive symptoms; reduction in problematic alcohol and tobacco use

Speculative: Enhanced psychological flexibility and personal insight; anti-inflammatory effects

Contraindications

Personal or family history of schizophrenia or other primary psychotic disorders

Bipolar I disorder or strong bipolar family history

Significant cardiovascular disease, uncontrolled hypertension (resting BP >140/90 mmHg), or recent cardiac events (MI or stroke within prior 6–12 months)

Pregnant or breastfeeding individuals

Key Interactions

Monoamine oxidase inhibitors (e.g., phenelzine, tranylcypromine, moclobemide; natural MAOIs in ayahuasca)

Antidepressants (SSRIs and SNRIs; e.g., sertraline, fluoxetine, venlafaxine)

Antipsychotics (5-HT2A antagonists; e.g., risperidone, quetiapine, ketanserin)

Lithium and other mood stabilizers

Stimulants and sympathomimetics (pseudoephedrine; excess caffeine)

Other serotonergic supplements (5-HTP, St. John's wort, high-dose tryptophan, tramadol)

Supplements with additive cardiovascular effects (yohimbine, high-dose synephrine)

Risk & Side Effects

High: Acute cardiovascular stimulation; nausea and vomiting; intense or distressing psychological reactions

Medium: Psychosis or psychotic symptoms in vulnerable individuals; hypomania or mania in bipolar-vulnerable individuals

Low: Hallucinogen persisting perception disorder (HPPD); headache

Speculative: Serotonin syndrome with serotonergic drug combinations

Monitoring

Marker	Target	Why
Blood pressure	< 120/80 mmHg at baseline	Identifies hypertension risk before a compound that raises blood pressure
Heart rate / ECG	Normal sinus rhythm, resting HR 60–100 bpm	Detects arrhythmia risk before adrenergic/serotonergic stimulation
Electrolytes (basic metabolic panel)	Sodium 135–145 mmol/L; potassium 3.5–5.0 mmol/L	Vomiting can disturb fluid and electrolyte balance

Cadence: Session-based: baseline screening before use; blood pressure and heart rate immediately before dosing, then every 30–60 minutes across the 8–12 hour acute window; electrolytes within 24 hours if significant vomiting; cardiovascular and psychiatric re-screening before any subsequent session (typically no sooner than several weeks later).

Qualitative Assessment

Psychiatric screening (structured history): no active or high-risk psychotic/bipolar features
Mood and well-being in the days following (afterglow vs. lingering distress)
Sleep quality on the nights after a session
Absence of persisting perceptual disturbances (no ongoing visual trails)
Subjective sense of insight, perspective, or behavioral change (e.g., reduced craving)
Anxiety or destabilization as a warning sign rather than a success marker

Mescaline for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment