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SAM-e

SAM-e molecule structureSAM-e molecule structure
(2S)-2-Amino-4-(((2S,3S,4R,5R)-5-(6-aminopurin-9-yl)-3,4-dihydroxyoxolan-2-yl)methyl-methylsulfonio)butanoate
S-Adenosyl Methionine, S-Adenosylmethionine, AdoMet, AdemetionineOpen in Piru
Psychoactive Class
Chemical Class

SAM-e is a naturally occurring1 compound found in all living organisms.2 It was discovered by Giulio Cantoni in 1952. People generally use it to treat depression, osteoarthritis, and liver disease,3 although its effectiveness for these conditions remains uncertain.1 Supplements commonly come in enteric-coated tablets.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold200 mg
Light400-800 mg
Moderate800-1200 mg
Strong1200-1600 mg
Heavy1600+ mg
Bioavailability
2-10%

Duration

Onset1.75-3 hours
Total8-12 hours

Subjective Effects

Subjective Effects not written up yet

Pharmacology

Pharmacodynamics

SAM-e acts primarily as a methyl-group donor, supporting the methylation of nucleic acids, proteins and phospholipids, as well as the synthesis of molecules such as epinephrine, melatonin and creatine. These reactions contribute to cellular growth, repair and membrane maintenance. SAM-e also participates in transsulfuration and supplies aminopropyl groups for polyamine synthesis after decarboxylation. It activates the enzyme cystathionine beta-synthase4 and has reported antioxidant, anti-inflammatory and neuroprotective actions, including a role as a glutathione precursor. Its participation in nicotinamide methylation may help limit choline loss from neurons, although this proposed contribution to its cognitive effects remains uncertain.

Pharmacokinetics

Oral SAM-e is absorbed in the small intestine and has low bioavailability, reported as 2-10%, with substantial first-pass metabolism in the liver. Approximately 50% is metabolized in the liver, and its highest tissue concentrations occur in the liver and brain. Metabolism proceeds through methyl-group transfer, followed by hydrolysis by S-adenosylhomocysteine hydrolase; subsequent pathways either regenerate methionine or produce cysteine. The cysteine pathway requires vitamin B6, while methionine regeneration involves folate, vitamin B12 and betaine. SAM-e weakly inhibits CYP2E1 in vitro.5 Enteric-coated oral tablets reach peak plasma concentrations after three to five hours, and the elimination half-life is about 100 minutes.

Interactions

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

AcetaminophenAminophyllineBenzocaineBenzyl alcoholCarvedilol
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Tolerance

Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.

Full Tolerance
Tolerance to many of SAM-e's effects develops over several weeks of prolonged, repeated use, with larger doses becoming necessary to produce the same effects.
Baseline Reset
Without further use, tolerance takes approximately 1–2 weeks to return to baseline.
Half Tolerance
Without further use, tolerance takes approximately 3–7 days to decrease by half.

Harm Potential

Addiction & Dependence

Psychological

Extremely Low

SAM-e is described as non-habit-forming, with little abuse potential and no apparent tendency to cause psychological dependence.

Physical

Extremely Low

SAM-e does not appear to cause physical dependence.

Toxicity

Mucous membranes and respiratory tract

SAM-e can irritate mucous membranes and the upper respiratory tract.

Nervous system

SAM-e can cause central nervous system depression, and supplementation has been associated with uncommon manic episodes, including in people without a history of mania.

Gastrointestinal system

SAM-e consumption can cause gastrointestinal disturbances, including dyspepsia, constipation, and nausea.

Systemic

Excess SAM-e produced harmful effects in laboratory mice, and toxicity was also observed in cultured human cells.

Carcinogenicity

SAM-e has weak DNA-alkylating activity.8

Evidence Basis
Animal Models
None
MechanisticNone

History & Culture

Giulio Cantoni first discovered S-adenosylmethionine (SAM-e) in 1952.9 Earlier observations in 1947 had linked the SAM cycle to liver disease through the accumulation of methionine in the blood of people with alcoholic cirrhosis.…

Legality

By Country

Controlled / restricted1
United Kingdom flagUnited KingdomRestricted
Prescription1
Germany flagGermanyPrescription only
Legal / decriminalized3
United States flagUnited StatesLegal (regulated)
Malaysia flagMalaysiaLegal (regulated)
Russia flagRussiaLegal (regulated)

References

Source Pages

  1. DrugBank
  2. Erowid: SAM-e Experience Vaults
  3. PsychonautWiki
  4. Wikipedia

Citations

  1. National Center for Complementary and Integrative Health, S-Adenosyl-L-Methionine (SAMe): In Depth. nccih.nih.gov (2017). https://www.nccih.nih.gov/health/sadenosyllmethionine-same-in-depth1234
  2. S-Adenosylmethionine: molecular, biological, and clinical aspects--an introduction. The American Journal of Clinical Nutrition (2002). https://doi.org/10.1093/ajcn/76/5.1148s1
  3. SAMe. Mayo Clinic (2025). https://www.mayoclinic.org/drugs-supplements-same/art-203649241
  4. S-adenosylmethionine metabolism and liver disease. Annals of Hepatology (2013). https://pmc.ncbi.nlm.nih.gov/articles/PMC40270411
  5. Inhibition of CYP2E1 catalytic activity in vitro by S-adenosyl-L-methionine. Biochemical Pharmacology (2005). https://doi.org/10.1016/j.bcp.2005.01.00712
  6. S-adenosylmethionine (SAMe). Drugs.com / Cerner Multum (2026). https://www.drugs.com/mtm/s-adenosylmethionine-same.html12
  7. Excess S-adenosylmethionine inhibits methylation via catabolism to adenine. Communications Biology (2022). https://doi.org/10.1038/s42003-022-03280-51
  8. Nonenzymatic methylation of DNA by the intracellular methyl group donor S-adenosyl-L-methionine is a potentially mutagenic reaction.. The EMBO Journal / Springer Nature Link (1982). https://doi.org/10.1002/j.1460-2075.1982.tb01149.x12
  9. S-adenosilmetionina: qué es. Clínica Universidad de Navarra (n.d.). https://www.cun.es/diccionario-medico/terminos/s-adenosilmetionina1
  10. S-Adenosyl-L-methionine (SAMe): from the bench to the bedside—molecular basis of a pleiotrophic molecule. The American Journal of Clinical Nutrition (2002). https://doi.org/10.1093/ajcn/76.5.1151s123

Further Reading

  1. Examine: .com SAM-e Overview
  2. Nootropics Expert: SAM-e Guide

Article Status

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