What Is the Follicular Phase?

You’ve heard of the four stages of the menstrual cycle—menstrual, follicular, ovulation, luteal—but, truth be told, it’s been years since you took a sex-ed class and you could use a refresher course. So, uh, what is the follicular phase exactly? Well, friends, it starts on the first day of your period, ends when you ovulate and happens to be the longest phase of a lady’s monthly cycle. It’s also a time of month when you might find yourself feeling like something of a rockstar. Now that we have your attention, read on for everything you need to know about this particular phase of your cycle—including why you might want to make the most of it.

As previously mentioned, the follicular phase begins on the first day of your period, lasts until ovulation day, and accounts for the first half of the menstrual cycle. In other words, the follicular phase always starts when Aunt Flow shows up, but its duration is typically between 10 to 17 days, and can even be as long as 27 days, depending on when ovulation occurs. During this time, your body is busy with some pretty important work. First, the hypothalamus gives the pituitary gland the signal to start releasing follicle stimulating hormone (FSH), which in turn prompts your ovaries to produce roughly five to twenty immature eggs, each of which is protected by a little sac-like follicle; then, the uterine lining thickens to prepare for a potential pregnancy and, if everything goes according to plan, one of these immature eggs will go the distance and, well, mature. (Hint: That’s when your fertile window starts.) Long story short: The follicular phase is when your body does its baby-making prep work.

Bloating, irritability, cramps—yep, PMS sucks. But being a woman isn’t all bad, friends. The silver lining is (you guessed it) the follicular phase. According to Dr. Premru-Sršen (M.D., Ph.D), staff OB GYN for Bellabeat Ivy, the follicular phase “is a great time within your body's natural cycle…a week where you’ll feel energized, positive, productive and vibrant, thanks to the increase in estrogen and testosterone levels.” The expert also tells us that many women experience a glowing complexion and a boost in libido during this period as well. Sounds pretty sweet, right? As such, the OB GYN typically encourages women to “[socialize], schedule important meetings, learn new skills and move their body more rigorously” during the follicular phase—namely because this is the time of the month when you’re most likely to be on your A game. 

Given that the follicular phase is the time of the month when you have tons of energy (and sex appeal, to boot), it makes sense to stay attuned to when it occurs. Fortunately, this is fairly easy to do, since the start date (i.e., the first day of your period) is pretty hard to miss. That said, the end of this magical window can be harder to pinpoint, since ovulation day can be unpredictable, particularly for those who have irregular periods. Ultimately, though, the day you ovulate—and the end of the follicular phase—is determined by the length of your cycle, so if you’re not satisfied with guesstimations, your best bet is to track your cycle closely. (Psst: A period tracking app such as Bellabeat Ivy or MyFlo can help.) 

As previously mentioned, the follicular phase, which overlaps with menstruation, can be as short as 10 days or as long as 27; it all comes down to how long it takes the egg to mature and be released by the ovary, a process that varies from woman to woman (and even month to month) and can also be affected, usually lengthened, by certain types of birth control. That said, the length of your follicular phase isn’t especially relevant unless you’re trying to get pregnant. Women who are hoping to conceive should know that a lengthy follicular phase has no impact on fertility, whereas an abnormally short follicular phase can indicate hormone levels that are less conducive to conception. It’s also worth noting that the follicular phase naturally shortens as women near menopause and corresponds with the decline in fertility that women begin to experience in their late thirties.

Chances are you’ll feel pretty swell (relatively speaking) during the follicular phase no matter what. But Dr. Premru-Sršen says that you can get an even bigger boost if you pay close attention to your diet at this time, and recommends eating “leafy greens, sweet potatoes and foods high in vitamin E for maximum impact and energy during this menstrual cycle phase.” In other words, if you want to make the most of the follicular phase, load up on veggies… and then bust out your day planner.