In the past year, weighted vests have become a fixture of the fitness world. It can be hard to walk in a park or on a hiking trail without seeing someone wearing one.

Many menopause and fitness influencers — some of whom make money on commission — pitch them as a way to add some resistance to walks, squats and lunges, or even turn housework into a workout. Some claim the vests can help women in midlife maintain strong bones and muscles. One influencer recently went so far as to call them “one of the best-kept secrets” for healthy aging.

Several companies that sell weighted vests have had recent boosts in their sales numbers, and in May, Peloton began offering weighted vest walks. But how effective are weighted vests, really? We asked fitness experts and exercise scientists to explain what the research shows.

Can they improve bone health?

For women who have gone through menopause, maintaining bone health is essential for avoiding falls and moving comfortably through daily life.

Bone density plummets in the five to seven years after menopause, and half of women older than 50 will break a bone because of osteoporosis. A large body of research suggests that exercise can indeed help to strengthen your bones by strategically stressing them.

While wearing a weighted vest could theoretically strengthen bones by putting more force on them, the research on vests and bone health is “not as clear as yet as we would like,” said Dr. Sharon Hame, a professor of orthopedic surgery at the David Geffen School of Medicine at UCLA. Most of the studies that have been conducted were small, and many had fewer than 20 participants. While some study participants who wore weighted vests did see improvements in bone density, others did not.

Notably, while social media influencers often recommend walking in a weighted vest for bone health, few studies have looked specifically at this use. One small study that did found no difference in the bone health of participants who wore vests compared with those who didn’t.

Other small studies have explored the potential bone health benefits of wearing a weighted vest during higher-intensity exercises such as jumping, or during resistance exercises like squatting and lunging. While many participants in these studies did see a positive impact on their bone health, the research didn’t fully reveal whether that was because of the vests or the exercises.

The effectiveness of a weighted vest would depend on factors like how heavy the vest is, how often you use it and the intensity of the activity you’re doing while wearing it, said Roger Fielding, an exercise physiology researcher and senior scientist at the USDA Human Nutrition Research Center on Aging at Tufts University.

For now, the Bone Health and Osteoporosis Foundation does not endorse weighted vests for bone health, explaining that the evidence is “uncertain,” and that more research is needed.

If you’re looking to strengthen your bones with exercise, any workout that requires you to support your own body weight is ideal. Progressive resistance training and exercises that involve moving in several directions (think dance or tennis) are especially effective, said Rebekah Rotstein, the creator of Buff Bones, a fitness program designed to help women build bone strength.

Can they help build muscle strength?

A well-rounded strength-training routine is important for postmenopausal women: Starting in your 30s, you lose up to 8% of your muscle mass per decade, and more after you turn 60.

While some small studies suggest that wearing a vest during resistance exercises may lead to modest improvements in muscle mass and strength, as with bone health, these studies don’t clearly reveal whether it’s the vest or the exercises that lead to these changes, experts said.

Weighted vests may help improve core and lower-body strength by putting additional stress on your lower back and leg muscles, Fielding said. But, perhaps counterintuitively, they don’t target muscles in the upper body, so you shouldn’t rely on them to strengthen your arms and chest.

“It’s not a trade for traditional full-body resistance training,” said Lauren Colenso-Semple, a muscle physiology researcher at McMaster University.

What can weighted vests do?

Most experts agreed that wearing a weighted vest can modestly enhance your workouts by making them harder. If you like to walk or hike, a vest may offer greater aerobic conditioning by putting more load on your body, which forces your heart, lungs and muscles to work more.

This may improve your overall fitness and endurance, Hame said.

And if you find that wearing a weighted vest motivates you to move more in general, the benefits could be even greater.

Here’s the bottom line

If you don’t suffer from back, neck, shoulder or joint pain, and you aren’t at risk for a spine fracture, there’s little harm in wearing a weighted vest, experts said.

If you choose to wear one, start with a vest that is 5% to 10% of your body weight to avoid injury — or lighter, if you haven’t exercised in a while. Gradually add weight as you build strength. If you wear a vest while doing housework, Hame said, be careful when bending or reaching to avoid losing your balance.

While a weighted vest may offer you some benefits, it’s hard to beat the evidence in favor of traditional strength training. “We have a wealth of data on what we can do for muscle,” Colenso-Semple said.