Is There A ‘Best’ Time For Women To Build Muscle? What A New Study Reveals

The findings may surprise you.

Kass

Apr 29, 2026 - 17:15

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Is There A ‘Best’ Time For Women To Build Muscle? What A New Study Reveals

Registered Dietitian Nutritionist

Image by jacoblund / iStock

April 29, 2026

Syncing your workouts to your menstrual cycle is a newish concept that's piqued the interest of women. For example, it's often encouraged to prioritize energy-intensive lifting and HIIT classes to align with your often more energized follicular phase and lower-intensive movement (like Pilates or yoga) during your more sluggish-feeling luteal phase. And while you always have to meet your body where it's at for a workout, are there any physiological benefits to structuring your exercise routine around your cycle?

So, let's dive into the potential impact of women's hormones on muscle and the unique cycle-syncing insights this study reveals.

Hormones, energy & muscles

Estrogen and progesterone are two hormones that characterize the menstrual cycle and influence how you think and feel during that time.

Estrogen:

When is it the highest? The follicular phase (typically around days 6–14)—peaking at ovulation.What you feel: During the follicular phase and ovulation, many women feel more energized, motivated, confident, and strong (which is also due to a slight increase in testosterone levels).Impact on muscles: Estrogen is an anabolic hormone—meaning its presence helps you build muscle and bone.

Progesterone:

When is it the highest? The luteal phase (typically days 17–28).What you feel: During the luteal phase, many women feel more fatigued, bloated, and hungry; less motivated; and more sensitive to stress. Impact on muscles: Progesterone has been shown to have catabolic effects 1 on protein metabolism (i.e., higher muscle protein breakdown).

Based on these known hormonal fluctuations and the general impacts of these hormones, researchers of this study hypothesized that muscle protein synthesis would increase more during the follicular phase than luteal in response to strength training.

But that's not what they found.

There's no evidence that menstrual cycle phases impact muscle growth or breakdown

A total of 12 women ages 18 to 30 with a regular menstrual cycle (and no current or recent use of hormonal contraceptives) completed the study. Even though 12 seems like a small number, it was a large enough group to showcase any significant findings since prior research in this area is so limited (thanks to the gender gap in research).

Each woman underwent two six-day study phases: one during their follicular phase and one during the luteal (these were confirmed via hormone blood tests).

During both phases, researchers then used muscle biopsies to measure muscle protein synthesis and muscle protein breakdown following a lower-body strength training exercise.

Overall, the researchers were able to conclude:

There is no evidence that menstrual cycle phases impact muscle growth or breakdown.Training does not need to be adjusted based on menstrual phases.Higher estrogen levels in the follicular phase don't seem to promote greater muscle protein synthesis.

How you feel in each phase does matter

This study is truly foundational in helping us better understand the muscular responses to exercise during different phases of the cycle. Although there is a fluctuation in hormones, it does not seem to impact your ability to build muscle. Avoiding higher-intensity workouts just because you're in your luteal phase means you're also missing out on the benefits of that exercise. However, these hormone fluctuations still impact how you feel—which can impact your workout.

So, maybe that doesn't mean always skipping a weight day during your luteal phase, but listening to your body and recognizing that you are not up for picking the heaviest weights that day. Or maybe you max out at six reps instead of eight. You should always allow for flexibility and work with your body's current state.

How to get the most out of your workout routine

Strength train 2+ times a week: Strength training is a vital part of any fitness routine. Aim to train all major muscle groups at least two times a week. If you're feeling fatigued during the luteal phase, you can always alter your routine by cutting reps, decreasing weight, or opting for a shorter workout altogether to support muscle gains without pushing yourself too hard. Not sure where to start? We have a four-week at-home strength training program outlined here. Start taking creatine: Creatine isn't just for gym bros. It helps everyone, especially women, build muscle and get the most out of their workouts. Research consistently shows that taking around 5 grams of creatine daily (even on rest days) helps you build more muscle than exercise alone. We recommend always taking creatine with taurine (like this supplement), as taurine further supports exercise and recovery.*Find strength and motivation in group fitness: If you know the hardest part of working out in your luteal phase is getting to a workout, consider signing up for a group fitness class. Being in a room of folks who are also prioritizing their health and fitness can be quite motivating and uplifting—which hopefully sparks your mood and energy.

The takeaway

While a woman's cycle is characterized by changing hormone levels, those hormones don't seem to impact muscle growth or breakdown. Exercise at any point of the month is beneficial for building muscle, and you don't have to tailor your workouts exactly to your menstrual phase.

If you're really looking to build muscle, strength training should always be a part of your weekly fitness routine. Adding a creatine supplement on top of that is just going to give you an edge.*

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.