Birth Control Can Negatively Affect Your Workout Results, Study Says

There are plenty of challenges when it comes to building more muscle. But, there might be another factor for young women specifically to watch out for. No matter how many weight lifting exercises or high-intensity workouts you incorporate into your routine, it's quite possible that taking birth control pills could impair your muscle gains. Read on to learn more, and next, check out The 6 Best Exercises for Strong and Toned Arms in 2022, Trainer Says.

A study compared the muscle growth of women on hormonal birth control and those who were not

close up hands opening birth control package — Shutterstock

A study published in The Journal of Strength and Conditioning Research examined two groups of active young women (ages 18 to 31)—those who took oral contraceptives and others who didn't—who completed a total-body resistance training program designed to build muscle over the span of 10 weeks. The group of women who were on hormonal birth control apparently developed 40% less lean muscle mass than the women who were not taking hormonal birth control.

Three times a week participants performed weighted exercises, at 75% of their maximum strength. Researchers found that the women taking birth control had lower levels of anabolic hormones (DHEA, DHEAS, and IGF-1), but higher levels of cortisol hormones (at rest and post-workouts).

Different hormones can have different effects on a woman's body and muscles

woman working out outdoors, stretching in matching workout attire — Shutterstock

Muscles can be directly and indirectly influenced by a variety of hormones in a woman's body. While the growth hormone (GH) and testosterone mainly tend to foster mass muscle growth and strength, "other hormones like cortisol, adrenaline, and noradrenaline help enhance the availability of glucose (which serves as a major source of energy and performance)," explains Dr. Jagdish Khubchandani Ph.D., M.D., a Public Health professor at New Mexico State University and medical researcher in the fields of public health, nursing, and medicine.

"Menstruation, oral contraception, our lifestyle, physical and mental state, and environment are [all] factors that are linked to these hormones," Khubchandani tells Eat This, Not That! However, some natural side effects of the menstrual experience without oral contraceptives—cramping, migraines/headaches, and severe PMS—can also be a hindrance in athletic performance and muscle growth due to low energy and fatigue, he says.

Muscle-building hormones such as DHEA and DHEAS are naturally lowered by oral contraception, according to Kimberly Langdon, M.D., an OBGYN and gynecologist for Medzino. In terms of gaining more muscle, these are essential hormones. Although, many oral birth control formulas lower women's DHEA/DHEAS hormones and androgen, "due to their type of progestin," or the pill's ability to prevent pregnancy, she explains.

It's always a good idea to speak with your doctor to explore options

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The oral birth control you decide to use may have side effects and hormonal changes, but they will always vary due to the formation of the pill and your individual body's reaction to the contraception. If you're looking for major muscle gains, do not supplement with steroids as a solution to building more muscle, Langdon stresses. Steroids can lower the effectiveness of birth control pills, so she recommends speaking to your doctor about switching to an IUD or another type of contraceptive to both prevent pregnancy and/or steady menstrual cycle side effects.

If you're a young woman who's trying to achieve muscle-focused fitness goals, this may be another obstacle to overcome. It's important to note that this is one study's findings. Not only are there competing studies that look at opposing results, but there's still much more research that needs to be done.