Beef tallow moisturizers and salmon sperm facials are gaining popularity among consumers seeking natural alternatives to synthetic skin care products, even as dermatologists and cosmetic chemists say these products lack robust medical evidence of effectiveness.

The products, which range from balms made from organ fat of beef cattle to treatments administered at high-end spas, are increasingly available on social media, at farmers’ markets, and through online retailers. Some experts attribute their rise partly to growing consumer concerns about chemicals in personal care products and messaging from the Make America Healthy Again movement that emphasizes natural foods and products.

But experts stress that the popularity of these animal-based products outpaces scientific evidence supporting their use, and they warn consumers to be skeptical of claims about their benefits.

The trend

Bryan Vander Dussen spent years as a dairy farmer before shifting to selling farm-raised beef. In the past year, he and his wife have been making another transition: cooking up recipes in their kitchen that turn organ fat from his animals into tallow balm that buyers are eager to slather on their skin.

One challenge is formulation. The products initially smell like pot roast.

“You see it everywhere, so we were like, ‘Why don’t we do this?’” Vander Dussen said. “Some of the feedback is, ‘We don’t want to smell like beef,’ so we add things like lavender and wild orange to kind of counter that potential beef smell.”

For decades, the cosmetics industry moved away from many animal-derived ingredients amid concerns about animal testing and disease outbreaks like mad cow, said Perry Romanowski, an independent cosmetic chemist who studies how skin care ingredients are formulated. For years, those concerns, along with the rise of vegan beauty products, pushed many brands to avoid animal-based ingredients altogether. But recently, some of those materials have started to reappear in skin care products and are often marketed as natural alternatives.

Jamie Moody, founder of Sonoma Mountain Beef in Northern California, said she started making tallow products in an effort to reduce waste. “Since the trend toward clean products remains strong, I believe the market will continue to grow,” she said.

Growing consumer demand

Interest in animal-based skin care products has increased significantly. Natalee Keenan, 31, a Pennsylvania resident, said she was looking for natural skin care products when she decided to give tallow a try. The first product she purchased felt beefy and heavy on her skin, but she recently found a whipped tallow balm scented with coconut that feels much lighter.

“I use it sparingly,” Keenan said, adding that a tiny bit has been enough to keep her skin feeling smooth.

Vander Dussen said he and his wife are “just kind of jumping onto the fad that’s already there.” He added: “In today’s world, it’s very important not only what you are putting on your face but where it comes from.”

Kelly Pratt, who owns a spa in Tampa, Florida, said demand for treatments like salmon sperm DNA facials has surged because clients report improvements over time. Cassandra Hutchison, an aesthetician who gives the treatments at the spa, said the ingredient is intended to repair skin and keep inflammation down. She said it helps with hydration, making skin look healthier and repairing damage to the outer layer of skin that keeps moisture in and irritants out.

Prices for these products vary. A tub of tallow balm at Target costs about $15 more than a tub of petroleum jelly. While some salmon sperm products like masks can be applied at home, many have to be applied at a spa, which comes with its own costs. Searches for terms like “beef tallow for skin” have jumped in recent years and remained higher than ever before, according to Google Trends.

Behind this surge are deeper consumer motivations. Corrin Dial, 32, owns Lowcountry Family Farms with her husband in South Carolina. Neither of them grew up farming, she said, but decided to try it after he got out of the Marine Corps.

Dial said she was looking for a natural balm for her baby about two years ago and decided to try whipping tallow. She said she thinks many people are coming to it to avoid chemical products, citing one customer who had cancer and was told by her doctor to be careful of anything she puts on her skin.

“A lot of people are moving away from the chemical stuff,” Dial said. “They’re trying to get into healthy eating and using more products where they know exactly where it came from.”

Norah MacKendrick, an associate professor of sociology at Rutgers University who has studied why consumers are worried about chemicals in their personal care products, said there has been a movement in recent years to embrace animal-based foods. “I think some of that is probably spilling over into the cosmetic world,” she said.

MacKendrick speculated that mothers, who as a demographic have become increasingly aware of how chemical substances affect children, are driving some of the move toward animal-based cosmetic products.

“We find that mothers are making these decisions for the household,” MacKendrick said. “Buying cosmetics for children or personal care products for children is considered high-stakes work.”

The skeptical view

Neither beef tallow nor salmon sperm have robust medical data to support their effectiveness, said Dr. Angelo Landriscina, a New York City dermatologist who has taken to social media to debunk what he sees as skin care misinformation.

Dr. Heather Rogers, a Seattle dermatologist, agreed there is no medical evidence that tallow on skin is helpful. She said it can be rancid and hard to use, and additives to make it smell more pleasant can be irritants.

Romanowski said consumers should keep their expectations realistic. Only a few skin care ingredients, including retinol, a vitamin A-derived ingredient commonly used to reduce fine lines and wrinkles, and niacinamide, a form of vitamin B3 that helps with redness and strengthens the skin, have strong evidence behind them. Others, he said, may offer only modest benefits that are difficult for consumers to notice.

Market pressures

Dr. Landriscina pointed out that ingredients like salmon-based skin care getting touted as “the hottest new thing” can be rooted in an idea that other cultures, especially in places like South Korea, are somehow ahead of the curve or have more innovation in their skin care. That is a bit different than the “back to basics” mentality that can draw people to ingredients like beef tallow. But he said whether people are interested in something old or something new, their skin care choices should be rooted in evidence.

Romanowski said the beauty industry is under pressure to constantly introduce something new.

“You should think of the cosmetic industry more like the fashion industry because you can only do so much with the shirt, right?” Romanowski said. “You can change the color, you can do some aesthetics thing, but it’s still a shirt and it’s the same thing with cosmetics.”