The 38-year-old from Seattle is among the first customers trying out a new service, "Hangover Heaven", which promises to "cure" his throbbing head, sweaty pallor and general feeling of death, all within 45 minutes.
"I knew I was going to drink too much," Justin, an aeronautics industry executive, told AFP with a fragile smile, as an intravenous (IV) drip fed nausea-reducing drugs into his left arm.
"It's been a guy weekend. We arrived on Thursday. Last night we went out to a club, drank too much, stayed up all night," he added, estimating he has slept for maybe three hours.
Justin -- who asks sheepishly not to give his surname -- was speaking on board the shiny blue-and-white "Hangover Heaven" bus, parked outside the Mandalay Bay casino on the southern end of the infamous Vegas Strip.
From the outside it looks like any other tour bus. Inside, the vehicle is rigged out not unlike an ambulance: IV tubes, pulsometers, attentive nurses, and, if it all gets too much, soothing, darkened bunks.
The new service, which launched on August 14, is the brainchild of doctor Jason Burke.
The trained anesthesiologist -- who still works in hospitals locally in his "day job" -- came up with the idea while working with patients in recovery rooms, after qualifying in 2001.
"Watching patients in the post-anesthesia care unit, I noticed they had a lot of the same symptoms that people with a hangover have: the nausea, the headache, aches and pains, disoriented feeling.
"And I thought maybe these medications that I'm using to treat them in the recovery room could work for a hangover," he said.
Happily for him, he lives in the Nevada gambling capital -- internationally renowned as a center for heavy partying and intoxication of all kinds, and, of course, the setting for the first of the blockbuster "Hangover" movies.
What's more, "when people come to Vegas and drink, they're much more prone to get a hangover because of the time span over which they drink, it's much longer and they get more dehydrated because they're in the desert.
"So it's the perfect set-up for hangovers," he said.
Burke was talking after welcoming AFP onto the bus outside Caesar's Palace, its latest stop on a constant circuit up and down the sun-soaked Strip to pick up and drop off customers.
The service offers to "cure" shell-shocked morning-after revelers of their hangover using a combination of anti-nausea and rehydrating drugs, as well as vitamins and other medicines.
The bus promises an "ultra-smooth ride" to spare queasy stomachs, a mid-section with four bunks, a rear lounge, a bathroom and a "private interview room for people who have sensitive medical issues they wish to discuss."
Debbie Lund, one of his nurses -- she is a trained emergency medical technician (EMT), currently doing a Masters -- said the first weekend went well, with over 25 customers in Vegas -- and hung over -- for various reasons.
"They come from all over the world, some of them are on business, some of them are on bachelor or bachelorette parties," she said, echoing her boss's explanation that Vegas provides a perfect storm for hangovers.
"People come over on a long flight, they tend to start drinking while they're on the flight... so they've started their binge already, they just carry on once they get in to Las Vegas," she said, holding up Jason's IV tube.
All of this care does not come cheap: there are two basic packages, "Redemption" and "Salvation", offered at the introductory prices of $90 and $150 respectively.
Both provide drugs by IV, but the premium option includes intravenous hydration, anti-nausea and anti-inflammatory medications, as well as vitamin supplements, which can "remain in your system for days after the therapy."
Burke says the service is pitched high: it aims at people in their 30s and 40s, who have an income of between $70-100,000 dollars. "It's definitely not for people who consume most of their alcohol through a funnel," he said.
"I think the people who really go crazy with binge drinking, this price point is not something they're considering. This isn't a 20-dollar treatment," he said.
While both sexes get drunk in Vegas, he says he expects about 80 percent of his customers to be men, and only 20 percent women.
"Men tend to be, 'Let's solve the problem, let's get it done, so I can get on with things'," he said. "Women tend to wait longer, and women are also much more nervous about the IV," he added.
Those willing to give video testimonials on the service's website are all male, describing drinking dizzying amounts of alcohol. Alex woke up with a hangover registering 11 out of 10, and a garbage can next to his hotel bed.
Justin, who didn't seem to have a problem with the needle, has in the meanwhile perked up.
"I feel better," he said, starting to recall details of last night's boozing, and saying he was glad he had pre-booked, as most of Burke's customers do. "I scheduled this for Sunday after a weekend of partying," he said.
His buddies were back at the hotel pool, drinking, he said. They were all due to leave Vegas the next day. Asked if he would join his friends for one last night of partying, Justin was clearly tempted.
"Maybe," he said, grinning.