I want to share this because I wish someone had shared it with me before I spent two months inhaling something that was apparently generating toxic gas in my lungs.
I started using THC-O vape cartridges in early 2022 when they were being sold at every smoke shop in my state. They were cheap, legal at the time, and marketed as a stronger version of regular THC. I typically took 3-5 hits per day, usually in the evening. The effects were pleasant — stronger and more sedating than the delta-8 carts I had been using, with a slight delay before onset that I came to expect.
After about three weeks, I developed a dry cough. Not severe. Not constant. Just an intermittent cough that appeared in the mornings and sometimes after taking hits. I assumed it was normal vape-related irritation and did not think much of it.
By six weeks, the cough was worse. It was producing small amounts of thin mucus. My chest occasionally felt tight during exercise. I still did not connect it to the THC-O specifically — I had been vaping various cannabis products for years without these symptoms.
At the two-month mark, I read an article about the ketene research from Portland State University. The description of delayed-onset lung damage from heated acetate esters matched my trajectory exactly. I stopped using THC-O cartridges immediately and switched to regular cannabis flower.
The cough persisted for approximately four more weeks after cessation before gradually resolving. I went to a doctor who found nothing abnormal on chest X-ray but noted that my symptoms were consistent with chemical irritation of the lower respiratory tract. She was aware of the ketene research and told me I had made the right decision to stop.
I am not a doctor. I cannot prove that the ketene from THC-O caused my cough. But I had been vaping for years without respiratory symptoms, the symptoms appeared three weeks after starting THC-O, and they resolved after I stopped. The timeline fits the research, and I am not willing to test the hypothesis further.
The bottom line: if you are going to use THC-O, eat it. Do not vape it. The acetate ester group exists to improve oral bioavailability, not to be thermally decomposed in your lungs.