They stand in line outside pharmacies from before dawn. They're hoping, dreaming, wanting.
"Can I buy two?" asked a hopeful, elderly gentleman.
"No, just one," came the curt reply.
He pleaded, "I've got a wife and a daughter, you see."
The pharmacy chain Boots had given "Nightline" a tip that a shipment of an anti-aging serum was arriving at a store on London's Oxford Street early one morning. Men and women young and old came crawling.
"Well, obviously for the wife. Not for me," spluttered a nervous man in his early 40s.
The shipment of serum lasted less than two hours. Many left unsatisfied.
"Some of them get upset," a sales clerk explained. "Because they've been waiting for a while and when they get here it's finished already."
Since time began people have been trying to reverse its ravages. Now Stewart Long, a mild-mannered product developer at Boots, thinks he cracked it. It's a serum called No. 7 Protect and Perfect.
"It makes your skin visibly younger looking in four weeks," Long said with confidence at his laboratory in Nottingham, England.
People believe him because Dr. Rachel Watson -- a renowned dermatology researcher at the University of Manchester -- endorsed the serum in an academic paper and then on television. She specializes in sun damage and skin aging.
My first question when I met Watson was this: Do you use this serum? The reply: "Yes, I do actually."
Protect and Perfect has been in stores since 2004, gathering a small but enthusiastic following. Then it was featured in a BBC documentary analyzing the claims of beauty products.
The bottle appeared on screen for less then three seconds. That's all it took for a 21-week stock to sell out in two days. Now Boots can't make the stuff fast enough.
After our chat with Long, "Nightline" went to the factory where the serum is made. They'd run out of bottles. The supplier can't keep up with the demand. For more than a month, 1,500 bottles of serum were rolling off the production lines every hour, 24 hours a day.
Watch your television for a couple of hours and chances are you'll see a commercial for some kind of anti-aging cream. The makers bombard us with science, with the names of ingredients, with the short time it'll take to make us to look visibly younger.
A lot of these products, including Protect and Perfect, contain Retinol. It's basically a vitamin that stimulates skin cell activity. It's also in Tretinoin, a powerful and expensive prescription drug used to treat acne and deep wrinkles.
But according to Long, Retinol isn't what makes his $20, over-the-counter potion work.
"It's the combination of ingredients," he said. "We don't believe there's a single magic bullet that can treat the signs of aging."
So why does Watson think Long is on to something? In the lab Watson applied the serum to 10 volunteers' sun-damaged forearms. She took biopsies on day one and day 12.
She claimed that the skin showed significant improvement. After 12 days there were more fibrillin strands, which give skin its elasticity, she said. But does she know why?
"Not entirely, to be completely honest with you," she answered.
A six-month, full clinical trial of the serum is now under way. Results are expected in January. Meanwhile the buying frenzy continues.