Dextromethorphan
Aliases: Dm, Dxm, Dex, Robo, Syrup, robotussin, robitussin
Summary
DXM polistirex is an extended-release formulation where dextromethorphan is bound to a sulfonated styrene-divinylbenzene copolymer complex (an edible plastic), resulting in significantly slower absorption and prolonged effects compared to DXM HBr. Duration can extend 12-24 hours with residual effects lasting up to 48 hours. The extended-release mechanism increases the ratio of unconverted DXM to dextrorphan (DXO) in the bloodstream, producing more physical/sedating effects and less intense psychedelic/dissociative effects compared to immediate-release DXM HBr.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral BA ~11% | 100-200mg | 200-400mg | 400-700mg | 700mg+ |
DXM Plateau Calculator
DXM dosing is weight-based — the same dose can produce very different effects depending on your body weight. DXM experiences are categorised into four distinct plateaus, each with progressively more intense dissociative effects.
Mild stimulation, music enhancement, and a light mood lift. Often compared to a mild alcohol buzz with added euphoria. Most social of the plateaus.
Euphoria, closed-eye visuals, and noticeable dissociation. Impaired motor coordination, slurred speech. Similar to being cross-faded. The most commonly explored plateau.
Strong dissociation, altered perception of time and gravity, flanging of vision and sound, intense closed-eye hallucinations. Motor control is significantly impaired — you should remain seated or lying down.
Full dissociation comparable to a high-dose ketamine "hole". Complete out-of-body experiences, loss of contact with external reality. Dangerous — risk of unconsciousness, respiratory depression, and medical emergency.
⚠️ Deaths have been reported at doses above 25 mg/kg. Always start low. Make sure your product contains only DXM as the active ingredient — no acetaminophen, guaifenesin, antihistamines, or pseudoephedrine.
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 19-60 min | 30-90 min | 2-3 hrs | 2-4 hrs | 6-8 hrs |
Effect Profile
802 reportsScores (1–10) curated from multiple sources:
- Effect keyword matching from PsychonautWiki catalog
- Validated against 802 Erowid trip reports
- Weighted by importance: core (×3), major (×2), minor (×1)
Moderate dissociative depth, motor impairment, and insight with mild mania
“If I do a huge line, I will k-hole.”
“If I moved my hand in front of my face and wiggled my fingers the tracers caused me to have 20 fingers floating through the air from that one hand, a trail of geometry left behind, my entire room...”
“Yeah, I would still dose, I was 15 years old, stupid and thought I was invincible.”
“Likely dosing higher amounts of DXM, and redosing 2CB throughout (likely nasally) I also am now even more interested in trying ketamine with other psychedelics.”
“I've been high on large doses (600mg) several times before and very much enjoyed it, and still been able to think with a new kind of insight and clarity.”
“It sounds like you wanted to get some deep insight into yourself, but instead your brain wanted to do art and be creative.”
“I had double vision, couldn't walk very well, couldn't read, could sorta talk but too fast and quite confusedly..”
“Getting double vision and highly noticeable floaters comprised of geometry.”
User Experience
Tolerance
Tolerance Decay
Tolerance to dissociative effects builds rapidly over consecutive days and decays over 1–4+ weeks; values are approximate and largely anecdotal. Cross‑tolerance with other NMDA antagonists is expected but not precisely quantified.
Cross-Tolerances
Effects
Aggregated from 802 Erowid experience reports