Source-backed half-life profile
LSD half-life calculator
LSD is a classic example of half-life and experience length refusing to be the same thing.
Every curve begins at 100%. No dose or measured body concentration is assumed.
X-axis: elapsed time. Y-axis: modeled percentage of the relative starting point remaining. The shaded band shows the reported half-life range. This is a mathematical visualization, not a personal concentration estimate.
What a careful reader should notice first
The selected curve can look modest compared with the duration people associate with the substance, which makes the distinction between pharmacokinetics and pharmacodynamics especially important.
Source angle
The source value should be read beside study design and measurement method, not as a complete explanation of duration.
Do not use it for
Do not use the parent-compound curve to estimate psychological effects, functional safety, or when an experience has resolved.
Best next step
Compare LSD with 1P-LSD and AL-LAD, then read the half-life-versus-duration guide.
LSD: evidence and interpretation notes
Why the displayed value is 3.6 hours
A placebo-controlled crossover study administered an oral LSD solution to 27 healthy participants and measured parent LSD and metabolites for up to 11.5 hours. The geometric mean plasma half-life was 3.6 hours, with individual estimates ranging from 2.4 to 7.3 hours. That observed mean and range are the basis for this page.
Another controlled-study analysis reported a 2.6-hour plasma half-life across two datasets and found dose-proportional pharmacokinetics with first-order elimination over the measured period. Rather than average 2.6 and 3.6 into a value no study reported, HalfLifeDB uses the newer formulation-specific estimate and retains the second study as evidence that design and modeling choices move the result.
| Evidence source | What it contributes | Important limit |
|---|---|---|
| Holze oral-formulation study | Direct 27-participant mean, range, metabolite measurements, and subjective-effect timing | Findings describe one oral solution in a controlled healthy cohort |
| Dolder study analysis | Independent controlled datasets and a 2.6-hour compartmental estimate | Different study conditions should not be merged mechanically |
| Passie pharmacology review | Broader historical and pharmacological context | Older source literature includes less sensitive analytical methods |
| PubChem identity record | Compound identity | It does not establish the selected half-life |
The same study separates concentration from experience
In the 27-participant study, reported subjective effects lasted an average of about 8.5 hours, while the parent plasma half-life was 3.6 hours. The timelines were related, but they were not interchangeable. The study also measured O-H-LSD, whose peak and elimination profile differed from parent LSD.
This makes LSD useful for learning what a half-life cannot mean. One half-life is not the end of an effect, and five mathematical half-lives are not a universal recovery threshold. Pharmacodynamics, receptor activity, individual response, and study setting remain outside the chart.
Reading the range instead of overreading the mean
The 2.4-to-7.3-hour range produces visibly different decline envelopes. The shaded band is not decorative uncertainty; it represents the range observed in that controlled cohort. A visitor should not use it to locate themselves inside the study distribution.
The careful conclusion is that modern controlled studies support a parent-LSD plasma half-life measured in hours, with meaningful study and participant variation. Psychological duration, functional safety, and impairment require separate evidence and cannot be calculated from the line.
Reading this curve
HalfLifeDB uses 3.6 h as a representative input for LSD. In the simplified model, about 1.0% remains after 24 hours and about 3% remains after five half-lives, or roughly 18 h.
This is a short curve. The modeled amount changes noticeably over the same day, while effects, metabolites, and safety questions can still follow a different timeline. The curve is relative: it does not estimate a person's measured concentration, effects, impairment, or time to clearance.
psychedelic context
Psychedelic duration is shaped by pharmacodynamics as well as pharmacokinetics, so subjective effects may not track a simple elimination curve.
- The curve does not predict psychological effects or functional safety.
- Metabolites and downstream receptor activity are not separately modeled.
- Published estimates may come from small or specialized study populations.
LSD timeline checkpoints
| Elapsed time | Modeled remaining | Reading note |
|---|---|---|
| 6 h | 31.5% | Long-tail portion of the model |
| 12 h | 9.92% | Low modeled remainder, not a clearance guarantee |
| 24 h | 0.98% | Low modeled remainder, not a clearance guarantee |
| 2.0 days | 0.01% | Low modeled remainder, not a clearance guarantee |
| 3.0 days | 0.00% | Low modeled remainder, not a clearance guarantee |
Nearby profiles by half-life
These entries sit near LSD within the psychedelic group when sorted by representative half-life. That makes them curve comparisons, not statements about equal potency, effects, or risk.
- Psilocybin (3 h)
- DMT (10 min)
Pharmacokinetics at a glance
| Representative half-life | 3.6 h |
|---|---|
| Reported range | 2.4 h to 7.3 h |
| Curve type | Normalized, first-order decline |
Selection note: A controlled study in 27 healthy participants reported a 3.6-hour plasma half-life and a 2.4-to-7.3-hour observed range after an oral solution.
Sources and evidence context
A linked record is not automatically proof of the displayed value. Study, labeling, review, and compound identity sources serve different purposes; notes below identify limitations when they are known.
- Research abstract Holze F et al. Pharmacokinetics and subjective effects of an oral LSD formulation (2019).Controlled crossover study in 27 healthy participants; direct basis for the 3.6-hour mean and 2.4-to-7.3-hour range.
- Full-text research Passie T et al. The pharmacology of lysergic acid diethylamide: a review (2008).Full-text pharmacology review used for historical and mechanistic context, not the selected modern estimate.
- Research abstract Dolder PC et al. Pharmacokinetics and pharmacodynamics of LSD in healthy subjects (2017).Controlled-study analysis supporting first-order elimination and showing a different 2.6-hour modeled estimate.
- Identity record PubChem Compound Summary: Lysergic acid diethylamide.Compound identity record; background only.
What this page does not answer
- It does not estimate impairment, intoxication, or fitness to drive.
- It does not predict urine, blood, saliva, or hair test results.
- It does not model repeated exposure, tolerance, withdrawal, or interactions.
- It does not replace clinician, pharmacist, toxicologist, or emergency guidance.
Continue with context
- All substance profiles
- Browse the psychedelic group
- Compare this curve
- Clearance and volume of distribution
- Bioavailability, route, and formulation
- Active metabolites and parent compounds
- First-order vs nonlinear kinetics
- Detection windows vs half-life
- Reading labels and source quality
Read the medical disclaimer, methodology, and profile review log before using the model for comparison.