From IV treatments to cold plunges here are the biggest anti-aging trends sweeping the nation

Whether you plunge into a pool of ice-cold water or try cryotherapy — which involves spending a few minutes in a below-freezing chamber — cold exposure has benefits that may help slow down the clock. 

Anant Vinjamoori, chief medical officer of longevity-focused healthcare company Modern Age, told Insider that cold exposure produces effective results in the short and long term.

A plunge into an ice-cold bath results in "a surge in the production of neurotransmitters such as epinephrine and dopamine," which have immediate rejuvenating and energizing effects, he said.

"Over the medium to long term, there is some evidence that cold exposure may reduce systemic inflammation, which is known to be a driver of many chronic diseases," Vinjamoori added. 

Many of these longevity centers offer packages or retreats that can be pretty pricey — sometimes upwards of tens of thousands of dollars a week — but longevity experts contend that they are some of the best places to get practical longevity guidance. 

"The truth is that most people are probably wasting time and money on products that will never materially help them," Matt Fellowes, an advisory council member at the Stanford Center on Longevity and cofounder of health insights platform BellSant, told Business Insider by email. "One exception are some of the clinics that cater to high-income adults, which are actually science-based and, most importantly, create highly personalized assessments and guidance for people – meaning, they only focus on what their specific bodies need." 

At Clinique La Prairie — a more than 90-year-old longevity center in Switzerland — the seven-day, six-night "premium revitalization" package includes longevity consultations, sleep quality assessments, DNA tests, personalized nutrition guidance, and personal training sessions, alongside luxury accommodation and limousine service for about $53,000. The program "stimulates cell regeneration, fights the signs and causes of aging, and reinforces the immune system through a four-pillared approach of medicine, nutrition, wellbeing, and movement," a spokesperson for Clinique La Prairie previously told BI.

There are less expensive options, however.

Research suggests that time-restricted eating patterns can result in health benefits for those with diabetes and obesity or even enhance the body's defenses against oxidative stress.  

"For me, the primary benefit of time-restricted eating is regulating circadian rhythms. Sleep quality almost always improves by limiting the consumption of calories in the evening hours," said Modern Age's Vinjamoori. 

Those who cut out animal protein— and stick to a relatively plant-based diet— are likely to live longer and healthier lives, according to studies. 

David Sinclair, a Harvard Medical School professor and longevity researcher, said that high animal protein diets really only help people feel better in the short term. 

"I'm convinced, and the data shows it from population studies, that a carnivorous diet is not a longevity-producing diet in the long run," he said on an episode of "The Knowledge Project Podcast."

In many of the world's Blue Zones— areas where people tend to reach the age of 100— people are likely to have a relatively plant-focused diet. 

There is research to suggest that exposing oneself to red light for five to 20 minutes may increase production of adenosine triphosphate, which is a compound that provides and stores energy for the cells. 

"While more research is needed to understand the full benefits and mechanisms of red light therapy, there is evidence to suggest it may be beneficial in improving certain skin conditions including acne, aging, hair loss, wound care, and sun damage," dermatologist Laura Buford previously told Insider. 

NMN, or Nicotinamide Mononucleotide, is a supplement that can help boost levels of a critical coenzyme in the body called NAD+. 

NAD+ is vital in facilitating metabolic processes and maintaining healthy cellular function.

Harvard Medical School professor Sinclair — who has studied the relationship between NAD+ and aging — said in an interview with the YouTube channel Reverse Aging Revolution that the human body uses NAD+ as "a measure of adversity." As humans get older, NAD+ levels decrease, which means the body's defense enzymes and repair enzymes take a hit, and humans "succumb to aging," Sinclair said. 

Since NAD+ is a large molecule, it's difficult to take it directly. Sinclair recommends taking its building blocks like B3, Nicotinamide riboside (NR), or NMN. 

"What we've discovered in people, in clinical trials, is that the closer you get to the NAD itself, the better the boost in NAD that you get," Sinclair said, which is why he recommends NMN. 

The herb, often classified as an adaptogen, has a host of health benefits that range from easing anxiety and stress to soothing arthritis to boosting cognitive function. Modern Age's Vinjamoori said that ashwagandha has been shown in research studies to reduce cortisol, a hormone associated with stress, and improve sleep in people with insomnia. 

Recent research has also shown that ashwagandha could be a promising agent in anti-aging treatments. A study published in the Journal of Clinical Medicine in 2020 found that ashwagandha may help maintain the length of the key proteins at end of chromosomes known as telomeres. Telomeres are often shortened in the process of DNA replication which has been pointed to as the main factor that "speeds up cell ageing and promotes degeneration processes" the study noted. 

Metformin, a pill prescribed for diabetes, is increasingly being used by biohackers as a way to improve how humans age and slow the onset of diseases like cancer, cognitive decline, and vision loss. 

The drug helps regulate blood sugar and decrease appetite, essentially giving the metabolism a boost and stimulating a cellular clean-up process known as autophagy, Insider reported. 

In his book Lifespan, Harvard professor Sinclair said he takes a gram of metformin every morning along with his yogurt in the hope that it will regulate his metabolism and help his organs remain younger and healthier, Insider reported. 

OpenAI CEO Sam Altman also said his personal antiaging regimen includes metformin. 

It's also used in kidney transplants to help an organ recipient's body accept new kidneys, Insider reported.

The pill can slow down cellular growth and reproduction which means it might be a way to "turn down troublesome age-related inflammation," which can contribute to age-related diseases like cancer and Alzheimer's, Business Insider reported.

Business Insider also previously reported that researchers have already seen rapamycin slow aging in flies, crustaceans, yeast, and mice. In humans, studies have shown that it may help improve immune function, especially in older adults.

Despite its potential to be a "fountain of youth," no one has really nailed down the right way to regulate the drug for aging.

Matt Kaeberlein, a longevity researcher studying rapamycin's effects on humans, previously told Insider that "the doses that people are taking off-label are all over the place," adding that, "it's the wild west."

The body's balance of hormones can shift with age and spur a variety of age-related conditions like weight gain, mood swings, fatigue, and lower sex drive, two longevity-focused doctors told Insider. As a result, they've seen an increasing patient interest in hormone therapy.

Modern Age's Vinjamoori told Business Insider that testosterone replacement has gained popularity among men and women as it has become clear that optimal testosterone levels can impact mood, libido, and even metabolism. 

"The importance of testosterone for women, in particular, is underappreciated — testosterone is actually the most abundant hormone in a woman's body and is the first hormone to decline with age," Vinjamoori told Business Insider. 

It's not just testosterone, but also sex hormones like estrogen and progesterone that are being sought out by patients. Vinjamoori said the options for hormone therapy range from pills to creams to patches to pellets.

Peptides, a broad class of anti-aging and performance-enhancing treatments, have taken off in recent years among bodybuilders, athletes, and biohackers.

They're essentially short chains of amino acids that neuroscientist Andrew Huberman has described as a "new kind of wedge in between supplements and prescription pills." Some of the most popular peptide treatments are ones that release human growth hormone and can improve fat loss and muscle repair. 

"Indeed, biohackers are very excited about it because you can practically make your body do certain things," Christian Angermayer, a major investor in the longevity sector, previously told Insider. 

Intravenous treatments have long been used in hospitals to administer drugs to patients. In recent years, they've become a fixture at spas, longevity clinics, and even luxury residential buildings as a way for clients to hydrate or get a boost of minerals or supplements.

At Six Senses, a luxury resort in Ibiza,  intravenous infusions are among the most popular treatments. "The direct delivery of certain nutrients via the bloodstream serves to have an instant impact on vitality whilst forming part of a broader approach to living well for longer," Dr. Tamsin Lewis, RoseBar's medical advisor, previously Business Insider.

A happy and healthy mind is essential for a long life. And a new study finds that spending time in a sauna can help those battling depression. 

The study involved a clinical trial of 12 adults with major depressive disorder. Over a period of eight weeks, researchers treated them with a combination of cognitive behavioral therapy and sessions in a sauna heated to about 101.3 degrees Fahrenheit for up to 140 minutes. After the trial, 11 out of the 12 participants no longer met the criteria for major depressive disorder. 

Individuals with depression often have a higher-than-average body temperature. When someone's symptoms improve, their body temperature normalizes, too. The study analyzed the question: If you drive up body temperatures, can you get the body's cooling systems to work faster and mitigate the symptoms of depression?

It's a little early to make definitive claims, but the study's lead researcher, Ashley Mason, eventually wants to gather enough clinical evidence for insurance companies to cover saunas as a depression treatment.