THCA vs THC is a before and after. THCA, tetrahydrocannabinolic acid, is what the living plant makes. It doesn’t get you high as it is. Heat knocks off part of the molecule and turns it into THC, which does. A vape pen heats its oil every time you draw, so a THCA vape delivers THC. The difference that matters on a label is legal and chemical bookkeeping, not what comes out of the mouthpiece.
THCA and THC side by side
| THCA | THC (delta-9) | |
|---|---|---|
| What it is | The raw, acidic precursor the plant produces (Vice, Weedmaps) | What THCA becomes once heated |
| Structure | Carries an extra carboxyl group, COOH (Cenikor) | Loses that group as carbon dioxide |
| Intoxicating? | Not in its raw form; it can’t bind the CB1 receptor (Cornbread Hemp) | Yes |
| When vaped | Converts to THC (WebMD) | Already THC |
WebMD puts it in two sentences: one can get you high and the other can’t, and when THCA is heated, smoked or vaped it turns into THC. The chemists’ word for that step is decarboxylation.
Is 30% THCA the same as 30% THC?
Not quite, and the gap is predictable. The carboxyl group THCA loses has weight, so a gram of THCA becomes about 0.877 g of THC. Labs use that factor on every certificate of analysis:
Total THC = THC + (THCA × 0.877)
So flower labeled 30% THCA works out to about 26% THC once it’s burned or vaped. It also explains a product you’ll see all over this site. Liquid diamonds are crystallized THCA, melted into terpene sauce, and they’re among the highest-testing vapes we carry, with a median of 87.8%. THCA isn’t a weaker cousin of THC. It’s THC that hasn’t been heated yet.
Why THCA gets its own label
Because of how hemp was defined. Until the new law takes effect, federal law measures hemp by its delta-9 THC alone, which left room for high-THCA products to be sold as hemp. That’s the whole reason a THCA vape exists as a category separate from a dispensary THC vape.
The law is changing. Hemp-derived THC vapes have been sold under the federal hemp definition. A law enacted on November 12, 2025 redefines hemp by total THC, counting THCA and delta-8, and caps finished products at 0.4 mg of total THC per container. Most of it takes effect on December 11, 2026. A separate part, excluding cannabinoids the cannabis plant can’t naturally produce, takes effect on November 12, 2026. Many states restrict these products already. This is general information, not legal advice; check your own state’s rules.
THCA vapes and THC vapes on this site
We list 16 vapes sold as THCA, all disposables, from TRĒ House, Papa's Herb and Modern Herb Co, which is sold through Pulsar. They run from $29.99 to $49.99, and none publishes a single THC percentage on its listing. The 1,389 state-market THC vapes are a different kind of product: made and tested inside a licensed state system, and 757 of them show a batch result.
| Cannabinoid on the label | Listings | Brands | Formats | Price |
|---|---|---|---|---|
| THCA | 16 | TRĒ House, Pulsar, Papa's Herb | 16 disposables | $29.99–$49.99 |
| Delta 8 | 19 | TRĒ House | 13 disposables, 6 carts | $16.99–$39.99 |
| HHC | 13 | TRĒ House | 12 disposables, 1 cart | $19.99–$49.99 |
| THCP | 16 | TRĒ House | 12 disposables, 4 carts | $19.99–$39.99 |
If you want a lab number on what you buy, the second group is where you’ll find it. Both start from the Weed Pen home page, and everything here is for adults 21 and over.
THCA and THC questions
Does THCA give a high?
Not raw. Heat converts it to THC, and a vape heats the oil every time you draw, so a THCA vape delivers THC.
Is THCA the same high as THC?
Once it’s heated, it is THC. WebMD notes that when THCA is heated, smoked or vaped it turns into THC.
What is stronger, THC or THCA?
THC is the active form. THCA converts to it at a rate of about 0.877 by weight, so 30% THCA becomes roughly 26% THC.
How much THCA is equal to THC?
Multiply THCA by 0.877. Labs report total THC as THC plus THCA times 0.877.
Is THCA legal?
It has been sold as hemp, but the federal definition changes on December 11, 2026 to count THCA toward total THC. Several states restrict it already.
Sources and method
- WebMD, “What Is THCA? Effects, Uses, and Differences vs. THC”; Vice; Weedmaps; Cenikor; Cornbread Hemp
- The Hemp Collect (liquid diamonds as crystallized THCA)
- Federal hemp definition: fiscal 2026 appropriations law, enacted November 12, 2025, as delayed by H.R. 6500, signed September 2, 2026
- Weed Pen catalogue: 16 THCA-labeled vapes and 1,389 state-market THC vapes
Catalogue figures are counts, medians and ranges over the listings on this site on September 19, 2026. Tested THC is the maker’s own batch result as shown on each listing; we don’t run our own lab tests. Products are for adults 21 and over, and cannabis laws differ by state.