Some days, you feel strong and unstoppable. Other days, it’s like your body betrays you and no one can explain why.
What most studies on women’s performance ignore one major detail: how their birth control is messing with their hormones.
Over 60% of women in the U.S. are on hormonal contraception, yet research still treats “the menstrual cycle” like it’s one-size-fits-all. It’s not.
This article breaks down exactly how oral contraceptives and hormonal IUDs could be impacting your training, recovery, metabolism, and more. You deserve real answers, not guesswork.
Although research on how menstrual cycle phases affect athletic performance is growing, the impact of hormonal contraceptives such as oral contraceptives and hormonal intrauterine devices remains understudied. This is notable given that over 60% of U.S. adult women and nearly half of female athletes use hormonal contraception, with oral contraceptives and intrauterine devices being the most common(1).
Yet many studies either exclude hormonal contraceptive users or do not report their hormonal status clearly.
Oral contraceptives introduce synthetic estrogen and progesterone, potentially altering physiological responses to exercise compared to natural hormones. In contrast, hormonal intrauterine devices typically do not suppress endogenous hormone production and may have effects similar to a natural (eumenorrheic) cycle.("Eumenorrheic" simply means having a normal, healthy period. One that comes regularly, lasts a few days, and doesn’t cause major pain or problems.)
However, only two studies have examined performance in intrauterine device users(2).
Estrogen appears to support muscle repair and growth, possibly through satellite cell activity and mitochondrial regulation(3).
Variations in estrogen levels, whether natural or synthetic, may influence energy metabolism, muscle function, and recovery. Animal studies show estrogen deficiency reduces strength and muscle mass, but human data are mixed. Some studies find no difference in muscle strength across menstrual phases, while others suggest quicker recovery in the mid-follicular phase, potentially due to increased satellite cell activation.
Overall, a clear link between hormone fluctuations and recovery remains inconclusive(4).
Recent systematic reviews and meta-analyses have emphasized the importance of examining how the menstrual cycle and hormonal contraception affect strength, recovery, and exercise performance in women.
However, inconsistent methods and unclear definitions of menstrual and
hormonal phases limit current findings, especially when comparing eumenorrheic women to hormonal contraceptive users. While meta-analyses highlight these gaps, narrative reviews offer a broader perspective by integrating diverse study designs, participant profiles, and outcome measures.
In this review, we summarize the physiology of the eumenorrheic
(natural) menstrual cycle and the most common forms of hormonal contraceptive, and how they influence metabolism, muscle strength, and recovery. We compare performance across hormone phases in both eumenorrheic and hormonal contraceptive users and call for more research on individual hormonal responses to better understand their role in female athletic performance.
A literature search was performed using PubMed and Google Scholar, focusing on studies that included recreational to elite athletes and clearly reported menstrual status, hormonal contraceptive use, and hormone phase measurements.
For clarity, muscular strength and power were evaluated separately from anaerobic performance, and a range of recovery markers was included to capture its complex nature.
Following puberty, females experience cyclical hormonal changes known as the menstrual cycle, governed by fluctuations in estrogen, progesterone, FSH, and LH. A typical eumenorrheic cycle lasts 23–38 days, with menstruation continuing until menopause around age 51.
The cycle has two main phases:
Figure: Visual representation of hormonal fluctuations across the menstrual cycle for an idealized 28 day cycle in (A) eumenorrheic cycles and (B) hormonal intrauterine device cycles, and hormonal fluctuations for (C) monophasic oral contraceptive users with a daily dose of synthetic hormones, which suppresses endogenous hormonal levels, as indicated by solid (estrogen) and dashed lines (progesterone). Adapted from Cabre et al., 2024(4)
Hormonal contraceptives deliver synthetic sex hormones that influence the hypothalamic-pituitary axis, suppressing gonadotropin-releasing hormone, FSH, and LH, which in turn reduces natural estrogen and progesterone production(6).
Hormonal contraceptives are widely prescribed to both athletes and non-athletes for contraception, menstrual regulation, managing amenorrhea, and supporting bone health(7).
Hormonal contraceptives are available in several forms, including oral contraceptives, implants, injections, patches, vaginal rings, and intrauterine devices, with oral contraceptives and intrauterine devices being the most commonly used in the U.S. They are classified as either combined (containing estrogen and progestin) or progestin-only.
Hormone type and dosage can affect physiological responses to exercise.
Combined oral contraceptives are the most prescribed, typically taken as a 21-day active pill followed by 7 placebo pills to induce withdrawal bleeding, not a true menstrual period. Combined oral contraceptives come in monophasic, biphasic, or triphasic forms, with monophasic pills being the most common and well-studied. These provide a consistent dose of estrogen and progestin, making them easier to manage for menstrual symptoms and cycle control.
Biphasic and triphasic pills vary hormone levels throughout the cycle, which can complicate training due to fluctuating hormone levels(4).
Hormonal intrauterine devices are long-acting devices placed in the uterus and release progestin locally, typically over 3 to 5 years. Unlike systemic hormonal contraceptives, they do not fully suppress endogenous hormone production, resulting in hormonal patterns more similar to a natural (eumenorrheic) cycle.
There are also non-hormonal (copper) intrauterine devices, used solely for contraception. Hormonal intrauterine devices work by thickening cervical mucus and partially inhibiting ovulation, and are commonly prescribed to manage menstrual symptoms, sometimes resulting in amenorrhea(8).
While female sex hormones primarily regulate reproduction, they also affect other systems such as cardiovascular, thermoregulatory, respiratory, and muscular systems(9).
Given the differences in hormone profiles between natural cycles and hormonal contraceptives use, these variations may influence metabolism and muscle performance. This article therefore focuses on how endogenous and synthetic hormones impact strength and recovery in active women.
Figure: Overview of physiological systems related to muscular strength and performance that may be directly or indirectly impacted by estrogen levels, and variations in hormonal profiles between eumenorrheic females and those using hormonal contraception. Both intrauterine devices and monophasic oral contraceptives suppress the endometrium through progestin, which can also indirectly impact metabolism and skeletal muscle [34]. Future considerations should examine inter-individual factors that impact related physiological systems, strength, and recovery over time. Adapted from Cabre et al., 2024(4)
Estrogen is a "master regulator of bioenergetics" in females, influencing substrate metabolism and utilization(9).
Variations in estrogen concentrations across the eumenorrheic menstrual cycle may impact substrate utilization. General consensus suggests decreased fat and protein oxidation, and increased carbohydrate oxidation in the Follicular Phase, and the opposite in the Luteal Phase(10).
Estrogen and progesterone impact resting energy expenditure. Resting energy expenditure tends to be higher in the Luteal Phase when these hormones are elevated. Limited research exists on substrate utilization during anaerobic exercise and in hormonal contraceptives users. The influence of hormonal contraceptives use on resting energy expenditure is unclear due to study heterogeneity.
Skeletal muscle growth and repair are influenced by protein turnover. Evidence suggests estrogen reduces protein oxidation, while elevated progesterone in the Luteal Phase may increase the oxidative disposal of amino acids, potentially creating a catabolic environment(5).
Studies evaluating protein turnover across the eumenorrheic cycle have inconsistent findings regarding amino acid flux and net balance. Research on protein turnover in hormonal contraception users is limited, with one study suggesting lower myofibrillar protein fractional synthesis rate in fed oral contraceptives users compared to eumenorrheic females(11).
Sex differences exist in muscle mass and sensitivity to hormones (testosterone vs. estrogen). Estrogen receptors are distributed in muscle, tendons, and mitochondria, potentially impacting performance and repair. Fluctuations in estrogen and progesterone across the eumenorrheic cycle may affect central nervous system function and voluntary muscle activation. Some studies suggest peak voluntary activation when estrogen peaks(12).
Research on the effects of the eumenorrheic cycle and hormonal contraception use on maximal strength (1RM), isometric dynamometry, and muscular power (jumps, sprints) is largely equivocal, with studies showing conflicting or no significant differences when evaluating group means. The inconsistency in findings is partly attributed to methodological heterogeneity and varied definitions of cycle phases and reproductive status. Limited research exists on the impact of specific hormonal contraception types and phases
on muscular strength.
Females may exhibit greater skeletal muscle fatigue resistance and faster recovery than males at equivalent exercise intensities(13). Elevated estrogen levels are hypothesized to enhance recovery through promoting vasodilation, improving blood flow for nutrient/oxygen delivery and metabolite removal, and reducing muscle damage and inflammation(14).
Research on recovery markers (e.g., CK, IL-6, blood flow, lactate clearance) across the eumenorrheic cycle is equivocal. Some studies show elevated inflammatory markers in the follicular phase, while others show no differences(15,16).
Hormonal contraception use may modulate recovery metrics. Some studies suggest reduced recovery or increased inflammatory responses in oral contraceptives users compared to eumenorrheic females, potentially linked to changes in heart rate variability and cortisol levels.
The impact of intrauterine devices on recovery appears less significant than combined oral contraceptives, potentially having no effect on vascular function in some studies. Conflicting findings highlight the need to understand hormonal contraception implications for training adaptations and recovery.
Existing research is limited by evaluating outcomes across only one menstrual cycle, which may not capture natural variability. Heterogeneity in methodologies, definitions of cycle phases, and characterization of hormonal contraception use (type, dosage, phase) are major limitations for comparing findings.
Few studies include hormonal intrauterine devices users despite their prevalence. The reliance on standard statistical approaches (group means) fails to capture significant intra-individual variability in hormonal responses and performance. Future research should include hormonal contraception users, repeat measures across multiple cycles, and focus on analyzing intra-individual data to support precision medicine approaches in female athletes.
Scientists have been trying to understand how the menstrual cycle and birth control affect things like energy, strength, and recovery in active girls and women. So far, when they look at group averages, they don’t see big differences between those who have regular periods and those who use hormonal birth control, or between different points in the menstrual cycle. But the truth is more complicated.
It's kind of like looking at a class of students and saying, "On average, everyone did okay on the test," without realizing that some students did really well while others struggled. Just looking at the group as a whole can hide the big differences between individuals.
One problem is that there are lots of different types of birth control and hormone patterns, both natural and from medication, and studies often don’t include enough variety. Also, many studies don’t focus on how each person reacts differently, even to the same hormone changes. That’s like testing how one type of shoe works for everyone, even though people have different feet, running styles, and needs.
To get better answers, future research needs to:
This will help coaches and athletes make smarter choices about training and nutrition that work best for each individual girl or woman.
STEEL has an entire line of incredible products women can use to get strong, fit, and lean including whey and dairy-free proteins, energy, endurance, recovery, gut health, heart health, and more, all formulated and ready to provide support for your health and fitness goals.
You can check them all out here.
References:
1. Martin D, Sale C, Cooper SB, et al: Period Prevalence and Perceived Side Effects of Hormonal Contraceptive Use and the Menstrual Cycle in Elite Athletes. Int J Sports Physiol Perform 13:926-932, 2018
2. Cabre HE, Ladan AN, Moore SR, et al: Effects of hormonal contraception and the menstrual cycle on fatigability and recovery from an anaerobic exercise test. The Journal of Strength & Conditioning Research:10.1519/JSC. 0000000000004764, 2022
3. Kitajima Y, Ono Y: Estrogens maintain skeletal muscle and satellite cell functions. J Endocrinol 229:267-275, 2016
4. Cabre HE, Gould LM, Redman LM, et al: Effects of the Menstrual Cycle and Hormonal Contraceptive Use on Metabolic Outcomes, Strength Performance, and Recovery: A Narrative Review. Metabolites 14:347, 2024
5. Draper CF, Duisters K, Weger B, et al: Menstrual cycle rhythmicity: metabolic patterns in healthy women. Sci Rep 8:14568, 2018
6. Myllyaho MM, Ihalainen JK, Hackney AC, et al: Hormonal Contraceptive Use Does Not Affect Strength, Endurance, or Body Composition Adaptations to Combined Strength and Endurance Training in Women. J Strength Cond Res 35:449-457, 2021
7. Rickenlund A, Carlström K, Ekblom B, et al: Effects of oral contraceptives on body composition and physical performance in female athletes. J Clin Endocrinol Metab 89:4364-70, 2004
8. Regidor PA: The clinical relevance of progestogens in hormonal contraception: Present status and future developments. Oncotarget 9:34628-34638, 2018
9. Van Pelt RE, Gavin KM, Kohrt WM: Regulation of body composition and bioenergetics by estrogens. Endocrinology and Metabolism Clinics 44:663-676, 2015
10. Oosthuyse T, Strauss JA, Hackney AC: Understanding the female athlete: molecular mechanisms underpinning menstrual phase differences in exercise metabolism. European Journal of Applied Physiology 123:423-450, 2023
11. Hansen M, Langberg H, Holm L, et al: Effect of administration of oral contraceptives on the synthesis and breakdown of myofibrillar proteins in young women. Scandinavian journal of medicine & science in sports 21:62-72, 2011
12. Phillips S, Rook K, Siddle N, et al: Muscle weakness in women occurs at an earlier age than in men, but strength is preserved by hormone replacement therapy. Clinical science 84:95-98, 1993
13. Ansdell P, Thomas K, Hicks KM, et al: Physiological sex differences affect the integrative response to exercise: acute and chronic implications. Experimental physiology 105:2007-2021, 2020
14. Tostes R, Nigro D, Fortes Z, et al: Effects of estrogen on the vascular system. Brazilian Journal of Medical and Biological Research 36:1143-1158, 2003
15. Hackney A, Kallman A, Ağgön E: Female sex hormones and the recovery from exercise: Menstrual cycle phase affects responses. Biomedical human kinetics 11, 2019
16. Romero-Parra N, Barba-Moreno L, Rael B, et al: Influence of the menstrual cycle on blood markers of muscle damage and inflammation following eccentric exercise. International journal of environmental research and public health 17:1618, 2020
