Δ9-Tetrahydrocannabinolic Acid (THCA)
Identity
| Property | Value |
|---|---|
| Preferred name | Δ9-Tetrahydrocannabinolic acid A (THCA-A) |
| IUPAC name | (6aR,10aR)-1-hydroxy-6,6,9-trimethyl-3-pentyl-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene-2-carboxylic acid |
| CAS number | 23978-85-0 (THCA-A) |
| PubChem CID | 98523 |
| InChIKey | FCHTHPIEJYEJOM-DUYOSMWVSA-N [^1] |
| Molecular formula | C22H30O4 |
| Molecular mass | 358.48 g/mol (exact 358.2144 Da) |
| Compound class | Cannabinoid acid; meroterpenoid (prenylated benzochromene) |
| Stereochemistry | Two stereocenters; natural material is (6aR,10aR). THCA-B (3-COOH regioisomer) is a distinct minor entity; Δ8-THCA (CAS 5957-75-5) is a distinct positional isomer [^1] |
| Major synonyms | THCA, Δ9-THCA-A, tetrahydrocannabinolic acid; decarboxylation product is Δ9-THC |
Identity notes
- Many COAs report “THCA” without specifying the isomer; THCA-A is the natural biosynthetic product, THCA-B is a minor isomer with a different retention time and melting point [^1].
- Δ9-THCA vs. Δ8-THCA have distinct CAS numbers (23978-85-0 vs. 5957-75-5) and must not be collapsed [^1].
- GC without derivatization converts THCA to THC in the injector and reports “Total THC”; the theoretical weight-conversion factor is 0.877, with empirical flower-matrix values lower [^2].
Physical properties
| Property | Value | Conditions / Notes |
|---|---|---|
| Melting point | ≈70 °C (with decomposition) for THCA-A; 184–185 °C for THCA-B (both reported in secondary sources; not independently verified) | THCA-A decarboxylates at melt [^2] |
| Boiling point | No compound-specific atmospheric boiling point was located. The often-repeated ≈437 °C value is not a verified THCA measurement; the atmospheric value remains unresolved [^4] | |
| Vapor pressure | No authoritative experimental data or compound-specific curve was located. The measured THC/CBD vapor pressures must not be transferred to THCA | Antoine parameters not published [^4] |
| logP (octanol-water) | ≈5.4–5.8 (predicted) | Highly lipophilic |
| Water solubility | <1 mg/L (very low) | Soluble in ethanol, methanol, chloroform, DMSO, oils |
| Thermal decomposition | In the cited vacuum-oven kinetic study, THCA-A decarboxylation rates were measured at 80, 95, and 110 °C in extracts/reference material; temperature, time, atmosphere, and matrix affect conversion, so no universal onset or completion temperature is assigned [^3] | |
| Oxidation sensitivity | Oxidation behavior is condition-dependent; CBN formation was observed in the cited heated analytical context, but no general stability rate is assigned [^3] | |
| Light sensitivity | Compound-specific photodegradation and UV thresholds remain unresolved; amber storage is a precaution, not a measured stability limit | |
| Known degradation products | Δ9-THC (decarboxylation), with CBN and Δ8-THC observed under cited heated analytical conditions [^3]; other high-temperature products remain unresolved |
Boiling point is not a device setpoint. No compound-specific atmospheric boiling point or vapor-pressure curve was located for THCA. The “437 °C” value is unresolved, and thermal behavior in plant matrix is governed by condition-dependent decarboxylation kinetics rather than a device temperature [^3][^4].
Thermal-extraction context
Thermal release of the THC series from botanical matrix involves decarboxylation of THCA to THC followed by vapor-pressure-driven evaporation of the neutral THC, but the conversion rate depends on temperature, time, atmosphere, matrix, and residence conditions [^3]. Device chamber temperature is not sample temperature; the thermodynamic boiling point of the pure compound is not a device setpoint or a sample temperature.
Cannabis occurrence
- Measured drug-type flower batches in legal-market COA datasets have reported ≈15–30% w/w (dry-weight basis) THCA for high-potency material [^8].
- Values are batch- and report-attached; no universal cultivar claim is made. Consult Lab Results for batch-level measurements.
Biosynthesis and processing
THCA is biosynthesized from CBGA by THCAS (THCA synthase) and competes with CBDAS and CBCAS for the shared CBGA pool; the THCAS/CBDAS allele balance defines chemotype I/II/III [^6]. Drying, curing, and heating convert THCA to THC, and prolonged oxidation yields CBN [^3].
Reported biological activity
Human evidence
THCA itself is the non-psychoactive precursor; intoxicating effects in humans are attributed to its decarboxylation product Δ9-THC. No controlled human study of inhaled isolated THCA was identified in this archive’s literature review (as of 2026-08-08).
Preclinical animal and in vitro evidence
Preclinical studies report THCA as a potent PPARγ agonist with neuroprotective activity in cellular assays 1 and COX-inhibitory activity among six major cannabinoids in vitro 2; these do not establish human effects at consumer-relevant doses.
Industry claims
“THCA flower is non-psychoactive until heated” describes the chemistry that THCA decarboxylates to intoxicating Δ9-THC on heating; product-legality claims are legal/market assertions outside this archive’s scope and are not assessed here. Health claims for THCA lack controlled human evidence 12.
Degradation products
- Primary: Δ9-THC (decarboxylation) 3
- Secondary: CBN and Δ8-THC under cited heated analytical conditions 3; quinone products remain unresolved
Sources
Related pages
- Cannabinoids Index
- CBGA Record (biosynthetic precursor)
- THCV Record (propyl homologue)
- CBD Record (competitive biosynthetic branch)
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Nadal X, Del Río C, Palomares B, Ferreiro-Vera C, Navarrete C, et al. Tetrahydrocannabinolic acid is a potent PPARγ agonist with neuroprotective activity. Br J Pharmacol. 2017;174(23):4263–4276. doi:10.1111/bph.14019. PMID 28853159. (In vitro/cellular assay.) ↩ ↩2
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Ruhaak LR, Felth J, Karlsson PC, Rafter JJ, Verpoorte R, Bohlin L. Evaluation of the cyclooxygenase inhibiting effects of six major cannabinoids isolated from Cannabis sativa. Biol Pharm Bull. 2011;34(5):774–778. doi:10.1248/bpb.34.774. PMID 21532172. (In vitro enzyme assay.) ↩ ↩2
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Wang M, Wang YH, Avula B, Radwan MM, Wanas AS, van Antwerp J, Parcher JF, ElSohly MA, Khan IA. Decarboxylation study of acidic cannabinoids: a novel approach using ultra-high-performance supercritical fluid chromatography/photodiode array-mass spectrometry. Cannabis Cannabinoid Res. 2016;1(1):262–271. doi:10.1089/can.2016.0020. PMID 28861498. (First-order decarboxylation kinetics; THCA-A Ea ≈85 kJ/mol.) ↩ ↩2
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Laboratory reports measuring this compound (1)
- Verified COA: Dragonberry 750ml (10mg) — Batch 250410-37-002 (InfiniteCAL) verified via 1 record(s)
Products with measurements (1)
- Dragonberry 750ml (10mg) — Powered By Plants verified via 1 record(s)