Does Birth Control Affect Muscle Growth?

A lot of women ask, does birth control make it harder to gain muscle? By how much does it affect muscle gain? What is the best birth control option if you care about muscle?

Birth control pills are one of the most popular contraceptives, with one study showing that 80% of sexually active women have taken them at least once. This is something, then, that could affect most women, especially at ages when they’re most eager to build muscle.

Birth Control Pills Probably Makes It Harder To Gain Muscle

2022 Study By Riechman et al.

A 2022 study by Riechman et al. looked at the results of 72 women, 20 years old on average, after doing 10 weeks of weight training. They did full-body workouts and trained three times per week, exactly as we recommend in our program.

The control group gained around 60% more muscle than those taking birth control pills. (Note that when we say “muscle,” we’re talking about gains in lean mass, which can include more than contractile muscle tissue.)

On the bright side, there weren’t any major differences in strength gains. Mind you, muscle size and muscle strength are very, very closely linked, and so those gaining more muscle will inevitably grow stronger. I suspect that the reason this study didn’t find a difference was because these women were still relatively new to lifting weights. With new lifters, differences in coordination and muscle activation can overshadow differences in muscle strength.

This is a fairly good study. The sample size was quite large (72 women), they used the gold standard of body composition measurement (hydrostatic weighing), and the effect size was fairly big.

Other Birth Control Studies & Muscle / Tendon / Bone / Collagen

Riechman’s findings also agree with some of the tentative findings of earlier studies.

A 2011 study: Here’s a quick snapshot with a conclusion from the study authors that oral contraceptives had a negative effect on myofibrillar protein synthesis. That will make muscle growth harder.

A 1985 study: This study is free to read (and well worth reading). Oral contraceptives might also have some negative effects on collagen, tendon, and bone synthesis as well.

There is one 2020 study that counters the previous studies, done by Oxfeldt and colleagues. In this study, the group taking oral contraceptives and the control group both gained similar sizes in muscle fibres over 10 weeks. It shows you can make killer gains while taking birth control pills—at least in the short term.

Why Would Birth Control Pills Make It Harder To Gain Muscle?

Birth control pills produce physiological reactions similar to those produced by androgens. If your androgen receptors are busy dealing with the androgenicity of the birth control pills, that can interfere with your androgen signalling, which could, in theory, affect your ability to build muscle.

In this study, we see that the women taking birth control pills with greater androgenicity gained the least muscle. The effect size is quite large, too, with the control group gaining 5x as much muscle as the women taking higher-androgenicity birth control pills. The study also found that the women taking birth control pills had higher levels of cortisol, the stress hormone. It’s conceivable that the increase in cortisol also affected muscle growth (and fat loss).

This is just one study. Take all of this with a dash of salt. But it’s possible that the type of birth control pills you take might play into muscle growth a little bit.

If you wanted to prioritize muscle growth, you might ask about taking birth control pills with lower androgenicity. But it’s still too soon to say if this effect will hold up with further research.

Do Birth Control Pills Slow Down Fat Loss?

The control group lost nearly twice as much fat as the group taking birth control pills, but this finding didn’t reach statistical significance. So it’s not unreasonable to suspect that birth control pills could make it harder to lose fat, and this study indeed shows that trend, but it may just be a coincidence.

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What’s cool about this study, though, is that these women weren’t even trying to lose fat. They were on a muscle-building program. They were gaining weight. And yet, in both groups, whether the women were taking birth control pills or not, they all finished stronger, leaner, and more muscular than when they started. So even if you’re taking birth control as a contraceptive pill, you ought to still see some improvements in your levels of musculature and body fat levels.

Best Birth Control For Muscle Gain

Different Types Of Birth Control

According to Medline (produced by the National Institutes of Health), birth control, also known as contraception, is using medicine, devices, or surgery to prevent pregnancy. These include:

• Barrier Methods
  • Male condoms
  • Female condoms
  • Contraceptive sponge
  • Spermicide
  • Diaphragm and cervical cap
• Hormonal Methods
  • Oral contraceptives—the pill
  • Contraceptive patch
  • Vaginal ring
  • Injectable birth control
  • Implant
  • Intrauterine method (IUD)
• “Other” Methods
  • Fertility-Awareness & Natural Rhythm Methods
  • Withdrawal
  • etc.

As we covered there are studies showing that hormonal methods might play a role in muscle gain, fat-loss, and potentially collagen, tendon, and bone disorders.

So what is best depends on you, your own circumstances, risk tolerance, opinion on using medicines, etc.

Summary

A high-quality 2022 study found that women who weren’t taking birth control pills gained 60% more muscle and lost twice as much fat as the women who weren’t. The good news, though, is that after ten weeks of lifting weights, eating slightly more protein, and eating in a slight calorie surplus, both groups gained strength, built muscle, and lost fat.

Plus, there’s other research showing the opposite—that taking birth control pills doesn’t affect muscle growth. So whatever decision you decide is best for you, you’ll be able to build muscle.

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