Part II (in a series) of some of the biggest research breakthroughs of the past year – This series will continue to include the best health and fitness trends and tips to help you stay strong in 2015. Use this information in 2015 to make this new year the greatest ever.

Healthy Men Keep Their Friends

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Plenty of research shows that solid friendships are key to living a long, healthy, happy life. Having even just one true friend (your wife and your dog don't count) can increase your life expectancy. On the flip side, loneliness can be as bad for your health as smoking cigarettes or getting sloshed every night. And yet, research also suggests that men too often let work, family, distance, and the everyday grind get in the way of maintaining old friendships and forging new ones. So make a new year's resolution to call up an old buddy or make plans with that former coworker you never see anymore. Or ask that guy you always yak with at the gym to grab a beer sometime. You'll be healthier for it.

You (Probably) Don't Need Low-T Drugs

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Past research has shown that Low T drugs may cause blood clots. Then this year  a big study  found that these overprescribed pills, gels, and creams can increase the risk of heart attacks in younger men who really don't need them. "This is a warning that testosterone therapy shouldn't be prescribed cavalierly," says Dr. Bradley Anawalt, a testosterone researcher at the University of Washington in Seattle. "Men with borderline low testosterone but without testicular or pituitary disease should be very cautious. These drugs are not a magic potion to restore youth, and there are risks." Pharmaceutical companies would have you think otherwise, though—even though there's no science to show that these drugs even work for guys in their 20s, 30s, 40s, and even 50s who don't have an underlying medical condition. If you're looking to boost your mood or get your swagger back, you'll likely have better luck by de-stressing, sticking to a workout routine, and eating more vegetables.

Skip the Steroids

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Steroid injections are one of the most common treatments for shoulder and back pain, but multiple recent studies have found that these shots work no better than physical therapy. "Although injections can help decrease pain in the short term, they don't address the underlying issue," says Daniel Rhon of Brooke Army Medical Center in Texas. "You might need more injections and more health care visits in the long run." More injections means more risk. "Steroids can weaken and damage tissue if used too often, and there's also a low risk of infection," Rhon says. Your other option, physical therapy, does in fact get at the root cause of pain and carries little to no risk. Plus, guys who get steroid injections often do PT anyway. Every aching back or sore shoulder is different, though, so definitely discuss all of your pain-relief options with your doc.

Stay Tuned For – The Biggest Health & Fitness Research Breakthroughs