Move over, argan oil and shea butter. Stylists are all abuzz about the latest miracle hair treatment: bull semen.

After reading about sperm-based facials, one British stylist began chatting away with her clients.

"When a client asked where she could get a sperm-based hair treatment done to feed her protein deprived locks … I was speechless," the stylist said on Stylecaster.com.

She did some research and came across a "Aberdeen Organic Bull Semen Treatment." Hari's, a salon in London, is offering clients a conditioning treatment made out of bull's semen. Hari's has been one of London's top salons for over 30 years and prides itself on offering some of London's most exciting new treatments sourced from around the world.

It has become the most talked about treatment in London. Touted as “Viagra for Hair," this 45-minute treatment ranges from £55 to £85 ($90-$138 U.S.) and uses semen from Aberdeen Angus bulls. Hari's combines the sperm with the root of the protein-rich plant Katera. The protein-enriched potion is massaged into the client's hair after it has been shampooed. Then the client is put under heat so the treatment penetrates the hair. The final step is the blow out, which gives the hair an awful lot of body, as well as shine.

"I have been searching for an organic product with a lot of protein because that is what hair is made of and that is what it lacks when it is dry," says salon owner Hari Salem. "The semen is refrigerated before use and doesn't smell. It leaves your hair looking wonderfully soft and thick."

Salem told media that he tried hundreds of products—including wild avocados and truffle oil—before hitting on bull semen as the elusive element in a formula for making hair look gorgeous. His salon also offers such treatments as Kerastase Hair Rituals and mind-soothing Indian Head Massage.

Salem says the treatment repairs, restores and brightens any hair. He says he has no shortage of customers.

"It will be an ongoing treatment as long as the bulls perform," he says.

According to CosmeticsDesign.com, the trend may actually have started with Norwegian based company Maritex, which stated that it was the main producer of Cod sperm for use in cosmetic products.

The company suggested that the sperm successfully binds water in body lotions and make-up, with the company said to have sold seven tons of processed cod sperm for use in cosmetics in 2002.

However, the motive behind the Hari's salon's decision to use the controversial ingredient was more scientific, with the protein in the semen thought to actively complement the protein contained in hair molecules.

Bull semen may be the latest attempt by hair manufacturers to find pure forms of protein that match the hair protein quantities in order to create the most effective hair care treatment. With the bull semen and Katira plant extract mix giving an almost instant and odorless finish, the treatment may be the start of big things to come, says CosmeticsDesign.com.

Because semen has to be refrigerated in straws until use, it could be a while before it becomes a staple in hair-care products. And with its high cost, the ingredient would be aimed at the premium hair care market.

According to Mintel data, other unusual animal ingredients are being used in Asia and Latin America, with many companies incorporating placenta ingredients into skin care products, according to CosmeticsDesign.

Sofface cosmetics, based in China, has created a make-up base that contains sheep placenta, while the Guangzhou Sisder Health & Beauty company has based an entire skin care and body line using the same ingredient.

And that's no bull.