Longevity's new muscle: Creatine

What we're hearing: Building muscle before old age is key to maximizing healthspan.

• Doctor and "Outlive" author Peter Attia says strength built now will define how mobile you'll be in the last 10 years of your life — think the ability to carry groceries (or not) in your 80s and 90s.
• Researchers also say strength training will add years to your life, and creatine can enhance its results.

For women, creatine is being praised more specifically as one of "the most important supplements" they can take.

• It's specifically a hot topic for women in perimenopause and menopause.
• Orthopedic surgeon Vonda Wright, who has said every woman should be strong enough to complete 11 pushups, takes 5 grams of creatine daily.
• Early research suggests benefits even in pregnancy.

How it works: As we age, we lose muscle (known in the medical community as sarcopenia) and can't move like we did in our 20s.

• Creatine is a compound that boosts energy. When taken regularly, people might have more energy to complete high-intensity exercises and see increased muscle growth.

Yes, but: An active lifestyle is required. "You can't sit on the couch" and expect to grow muscle, cautions David Brady, chief medical officer at supplements company Designs for Health, who tells Axios he takes a creatine supplement while working out.

Brains get a boost on creatine, too, research suggests. The supplement has been linked to improved memory, brain health, depression treatment and increased energy.

How much creatine, for how often and paired with what diet and exercise is largely an individual equation.

• The recommendation from supplement companies is typically 5 grams a day, with a loading period of more at the start.
• Some people have reported surprisingly good results in 30 days, while others in a recent small clinical trial didn't see much difference over 12 weeks.

• There's little harm in trying it: A recent meta-analysis of hundreds of studies found little to no negative side effects from the supplement.

Creatine is in food, but you'd have to eat a steakhouse-sized portion of red meat or seafood (up to 2 pounds) every day to hit 5 grams.

• In fact, we worked with a dietitian to try to identify a healthy creatine-rich diet as an example for this story, and they ultimately determined supplementation was the easiest way to consistently hit 5 grams without vastly increasing calories and cholesterol to unhealthy levels.

Reality check: While creatine can boost muscle, it isn't required to build muscle in the same way that protein is needed.

• If your goal is to live healthier than the average American, that can usually be achieved through adjustments to food, exercise and sleep, Angel Planells, spokesperson for the Academy of Nutrition and Dietetics and a Seattle-based dietitian, tells Axios.
• "A supplement isn't a cure-all, fix-all," Planells says.

What we're watching: Creatine research focused on Alzheimer's prevention and treatment.