Nikolskoe, Russia (CNN)It's no secret that Russian President Vladimir Putin is proud of his physique -- he has been photographed topless on horseback, or reeling in a fish. But what's behind the stamina of this 65-year-old, now contesting his fourth presidential election? Deer antler blood has something to do with it, he apparently believes.
Russians soak up the 'power' of Siberian red deer blood
Local media reports say that Putin is one of many Russians who have consumed and bathed in blood from the severed antlers of Siberian red deers. Bathers believe the blood gives them strength and stops the aging process.
On top of the controversial ritual of blood bathing, the belief fuels an entire industry of antler blood-based products, which animal rights groups say are barbaric and have no basis in science.
There is no evidence that velvety deer antlers or their blood have a healing effect, but some Russian research institutes have suggested further study into it.
Antler harvesting is not for the faint hearted. Each year, the animals are restrained as farmers use a saw to sever their horns.
CNN visited one of these farms high up in the picturesque Altai Mountains, in Nikolskoe.
"Of course it's not a drug," farm manager Ludmila Korotkhih told CNN.
"It's more of a supplement. But it makes our immune system strong, heals the body and gives us great strength, men's libido in particular."
The farmers here say it's no big deal for the animals as they grow a new pair of antlers each year. But when they do grow back, they are sawed off again, and this happens around 15 times in the lifetime of each deer.
The farm has more than 1,000 deer, and the farmers begin cutting off the antlers when the animals are around 3 years old.
Alexei Steinbrecher, a herder at the farm, talks about his trade with pride and describes it like a sixth sense.
"How do I even explain it?" he said, standing among a herd of deer. "I just feel it, when the antlers are ripe and ready. I just see it."
Many other farms operate in the Altai region, producing antler blood creams, pills and alcoholic drinks, and they offer baths in what they call "antler broth."
Some of the products are sent to Asian countries, such as China and South Korea, where there is a similar belief in the blood's health benefits.
Despite the lack of scientific evidence, the people at the Nikolskoe farm say they have had high-profile Russian athletes, including Olympians, visit for antler blood treatment.
Russian Prime Minister Dmitry Medvedev is also reportedly among consumers.
Korotkhih doesn't see the practice going away any time soon. In fact, he sees deer antler blood as a growing industry.
"People in the Altai have been using the antlers for a very long time," he said.
"At first it was a very local thing but then the word spread and there is now a lot of research being done, looking into the use of antlers."