See an updated version of this post on The Leaf Online,Cannabinoid Profile – THCa!
Formula: C22H30O4
Molecular Mass: 358.4733 g/mol
Decarboxylation Point: ???
Boiling Point: 105 °C (220 °F)
LD50 (Lethal Dose): 5628mg/kg for rats (Compare to Nicotine: for mice – 3mg/kg, for humans – 40–60 mg/kg)
Found in the trichomes, Tetrahydrocannabinolic acid (THCa) is the acidic precursor to THC, which actually exists in only minute quantities in the living plant. In living cannabis, THCa is the most abundant cannabinoid and terpenoid, potentially reaching over 30% of the dry weigh of the cannabis. Once the plant is harvested it begins a clock where, over time, the THCa begins to be converted into THC, a process quickened by exposure to heat and sunlight. One main reason cannabis is cured is to convert the THCa into THC, as well as drying it out to make it easier to burn, thus releasing the remaining THCa as THC. Knowing about decarboxylating cannabis is crucial in making edibles, where one pre-cooks the bud before making it into butter to raise the potency by converting THCa into THC.
Like all cannabinoids that exist in the living cannabis plant, THCa is non-psychoactive, though it still stimulates the appetite like THC. It also is a powerful anti-inflammatory, helps fight cancer and other tumors, aids with sleep, and more. Also like THC, an oral test has already been developed to detect THCa. While some sources show THCa to be a stable compound, Aphios research chemicals claims that it is very unstable and will breakdown into THC within weeks. It may have to do with the preparation of synthesized THCa used in their laboratory versus an active live-plant based THCa, but without further research the stability of THCa and how quickly it converts to THC is unknown.
Therapeutic Uses
Analgesic – Relieves pain.
Anti-Emetic – Reduces vomiting and nausea.
Anti-Inflammatory – Reduces inflammation.
Anti-Insomnia – Aids with sleep.
Anti-Proliferative – Inhibits cancer cell growth.
Antispasmodic – Suppresses muscle spasms.
Modulates Immune System – THCa has been shown to both improve and potentially suppress the immune system functions.
Neuroprotective – Slows damage to the nervous system and brain.
Currently Being Studied For
Anti-Emetic: THC has long been recognized as a valuable tool in combating nausea, but research done in 2013 found that THCa may be even more effective at preventing nausea and vomiting than THC. This means that patients suffering from nausea who do not want the psychoactive effects of THC should consider THCa.
Cancer: Many sources online claim that THCa helps fight cancer, but few studies have been done examining the cancer-fighting properties of this non-psychoactive cannabinoid. This 2011 study hints at the anti-tumor properties of THCa but its main focus was on the interaction of various cannabinoids and the TRP protein receptor channel. A 2013 study looking at prostate cancer also found THCa to be effective but did not elaborate on the mechanisms used or recommend further study.
Lupus: While no formalized studies are being done on THCa and Lupus, Dr. William Courtney and his wife Kristen have anecdotally demonstrated that fresh juiced cannabis high in THCa can control Lupus. As Kristen is still alive and managing her Lupus this study is ongoing, and still a success.
Neuroprotective: A 2012 study done on cell cultures shows that THCa may be a mild neuroprotective compounds for certain classes of brain cells, preventing unwanted cell death. These effects do not seem as notable as the neuroprotective qualities of THC and CBD but they are certainly worth more research.
The THCa/CBGa Process: Cannabigerolic acid (CBGa), CBG, THCa, THC, CBD, and CBC are all related compounds formed from the same chemical processes. CBGa and THCa are the originator compounds that appear to morph into the others. This linkage was explored in this 2012 study but needs further research to fully understand the mechanisms it works through.
*Note: Decarboyxlation – A chemical reaction that removes a carboxyl group and releases CO2, often triggered by heat or exposure to sunlight.
Well Suited For Life 
The two studies you sight in the cancer section as evidence of cancer killing potential are actually studies done on plant biochemistry and have nothing to do with cancer. If there are any studies that suggest cancer killing or cancer inhibiting potential of THCA please list them otherwise it should not be credited as anti cancer if there is no evidence to support the claim.
You are quite right and that is what I get for glancing over the abstracts without digging in a little more. THCa has been shown to help with cancer but those linked studies provide better evidence of its insecticidal properties.
Here are a couple studies on its cancer fighting properties.
As with virtually all cannabis research actual scientific studies are limited due to the government’s block on any research.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570006/
http://www.ncbi.nlm.nih.gov/pubmed/21175579
Most ‘sources’ are websites like this one (http://www.cbdscience.com/thca-tetrahydrocannabinolic-acid.html) that make claims without the backing of research. Thankfully we have the cannabis research laboratory SteepHill to step in and provide evidence from their testing that THCa is anti-tumor (http://steephilllab.com/resources/cannabinoid-and-terpenoid-reference-guide/).
I’ll go edit the post with those new links monumentally. Thank you for bringing my sloppiness to my attention.
Thank you very much for bringing those errors to my attention Matthew, and thank you for reading!
Thank you for taking the time to read my comment and act accordingly. I appreciate that (p.s. sorry for very late reply, but I didn’t get any notification of your reply and only came across it today)