Caffeine
Caffeine is a trimethylxanthine in which the three methyl groups are located at positions 1, 3, and 7. A purine alkaloid that occurs naturally in tea and coffee. It has a role as a geroprotector, a mutagen, a central nervous system stimulant, a psychotropic drug, a diuretic, a xenobiotic, an EC 3.1.4.* (phosphoric diester hydrolase) inhibitor, an EC 2.7.11.1 (non-specific serine/threonine protein kinase) inhibitor, an adenosine A2A receptor antagonist, an adjuvant, a food additive, a ryanodine receptor agonist, an adenosine receptor antagonist, a mouse metabolite, a plant metabolite, a fungal metabolite, an environmental contaminant and a human blood serum metabolite. It is a purine alkaloid and a trimethylxanthine.
IUPAC: 1,3,7-trimethylpurine-2,6-dione
PubChem
Physical & Chemical Properties
| Melting Point | 460 °F (NTP, 1992) |
| Boiling Point | 352 °F at 760 mmHg (sublimes) (NTP, 1992) |
| Density | 1.23 at 64 °F (NTP, 1992) - Denser than water; will sink |
| Solubility | 10 to 50 mg/mL at 73 °F (NTP, 1992) |
| Vapor Pressure | 0.00000001 [mmHg] |
| pH | pH = 6.9 (1% solution) |
| Appearance | Caffeine appears as odorless white powder or white glistening needles, usually melted together. Bitter taste. Solutions in water are neutral to litmus. Odorless. (NTP, 1992) |
Data: PubChem · Last updated: 4/20/2026
GHS Classification
No GHS classification data available.
Classification data is sourced from ECHA.
Regulatory Compliance
Listed
note: Status based on EPA TSCA Active Inventory · inventory name: TSCA Chemical Substance Inventory
View sourceGlobal Trade Intelligence
No trade flow data available for this chemical.
HS Code(s): 2939
Data: UN Comtrade
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