Stem cells have been touted as treatments for everything from hair loss to heart disease.

But are those claims scientifically sound?

Research on the technology continues to look promising, but many of its human applications are still preliminary and their effectiveness anecdotal.

Samumed, a $12 billion biotech start-up based in San Diego, profiled this month in Business Insider, exemplifies both sides of the coin.

The company has promised a bevy of age-reversing cures, including regrowing hair, treating wrinkles, and regenerating cartilage in people with osteoarthritis

However, their research isn’t conclusive.

None of their treatments have received government approval yet.

Read more: Rheumatoid arthritis and stem cell treatments »

Science and secrecy

It’s easy to get excited about all this research.

“Samumed Is Trying to Create the Fountain of Youth,” says one headline.

“Samumed Aims to Reverse Aging with Eternal Youth Treatments,” says another.

Combined with $300 million in investment funding, the company has more than just buzz going for it in the biotech industry.

Their treatment for androgenetic alopecia (hair loss) is currently in phase II trials.

Its program to help people with osteoarthritis regrow cartilage in their knees is in phase III.

In total, the company has seven drugs in phase II trials, with plans to expand into more areas of disease research this year.

However, Samumed has raised some eyebrows in the industry with its secrecy. Some skeptics have likened the company to Theranos, a biotech start-up that was valued at $9 billion before an investigation by the Wall Street Journal led to a shutdown of the company’s labs.

Samumed has been more open about presenting their data to the public — but not about the actual treatments.

“We're basically telling everyone, here's proof that it works,” Samumed Chief Executive Officer, Osman Kibar, told Business Insider. “How it works — you just need to wait a little longer because we want to build as much of a head start as we can.”

Read more: Stem cell treatments for multiple sclerosis »

Other stem cell research

Beyond the applications of stem cells at Samumed, the technology is also being used to treat some of the United States’ most widespread health issues.

New research from the American Heart Association this month demonstrated the effectiveness of implanted stem cells into the hearts of people with cardiomyopathy.

Although the sample size was small (only 27 people), scientists noted “function and symptomatic improvements” of heart functioning as well as less frequency of hospitalization and lower medical costs. They conclude that the stem cell procedure is “a feasible treatment for cardiomyopathy,” but they note that a larger clinical follow-up is needed for more conclusive results.

In the past week, Newsweek reported on “miracle” stem cell treatments for burn victims that will promote healing without scars.

Stat News wrote about research on stem cells in mice that could potentially help cure Parkinson’s disease.

Read more: Unproved stem cell treatments offer hope and risk »

Measured optimism

Some researchers in the industry are somewhat measured in their optimism of the technology’s human applications.

“I want to make sure that we provide a real cautionary note, especially to those individuals and those institutions that tout stem cells as the panacea for any ill,” Dr. Cato Laurencin, director of the Institute for Regenerative Engineering at the University of Connecticut, told Healthline.

Laurencin, a medical practitioner at the forefront of stem cell technology, is a firm believer in the benefits of the treatment, but also remains skeptical of some of the claims associated with it.

“Much of the evidence is still preliminary or anecdotal, and when people operate on information that is preliminary or anecdotal, there is the possibility for harm,” he said.

His work in regenerative engineering — a term he coined several years ago — looks at the healing properties of implanted stem cells in the human body.

In research published this month, Laurencin and his team concluded that stem cells effectively improved healing to torn rotator cuff tendons in rats.

Rotator cuff tendon tears are a relatively common injury in humans and can be difficult to treat.

Unlike other tendons in the body, the rotator cuff tendon is unable to heal itself, said Laurencin.

Once it is torn, it is liable to be reinjured again and again.

However, the research released this month is about more than just applying stem cells to a certain kind of injury, it’s about how the stem cells are applied.

Read more: Scientists use 3-D environment to speed up growth of stem cells »

Nanotechnology and other advances

Laurencin describes his field as an evolution of earlier work from 30 years ago in tissue engineering: a convergence of “bringing together new technologies to create new science and new possibilities.”

In this case, nanotechnology is at the heart of this stem cell operation.

Currently there are a variety of ways that stem cells can be implanted into a subject, including injections and bone marrow transplants.

For his research, Laurencin and his team used “biomaterial based fiber matrices” — a nanomaterial conducive to growing and attaching stem cells — to implant into the wounded area.

The results are promising, but Laurencin and his team will have to continue working with animals for some time before the process can be applied to humans.

The key is in understanding that stem cells have the potential for more than just regrowing damaged parts of the body.

“The way we commonly think about a stem cell is it becoming a new tissue. But we’re also understanding that the stem cell itself can secrete biological factors that help regeneration occur. That’s what we think is happening here,” said Laurencin.

His research into stem cells as a medicinal element in the body could have far reaching implications for all kinds of wound therapy.

Despite his measured approach, Laurencin is still willing to hypothesize about the excitement that the future of the field undoubtedly holds — with proper time, funding, and research.

“There are newts and salamanders that can regenerate a limb,” he told Healthline.

“How do we harness the cues that are taking place in these types of animals, and can we utilize what we’ve learned from these types of animals in humans?”