WTF is a luteal phase? Why is instagram telling me it’s normal to feel uglier at certain times of the month? How is it that I get my period at the same time as my best friend? 

For decades, menstrual cycles were treated like inconveniences: something to hide, manage, or push through. But understanding your cycle can actually be powerful. It gives you insight into why your energy, mood, and motivation shifts. You are not inconsistent, you’re just cyclical. 

Once you start noticing your phases, you may realize that your body is just communicating with you. So next time you’re crying during a dog food commercial or feeling like the most charismatic person at brunch, just know there’s a reason why!

What is the menstrual cycle?

It’s the monthly hormonal process your body goes through to prepare for a possible pregnancy. It starts on the first day of your period and ends the day before your next one begins. Throughout the cycle, hormones like estrogen and progesterone rise and fall, triggering your ovaries to release an egg (ovulation) and your uterus to build up a lining to support a pregnancy. If pregnancy doesn’t happen, that lining sheds… and that’s your period. The whole cycle typically lasts anywhere from 21 to 35 days, though the average cycle is 28 days (the same amount of birth control pills in your monthly pack!)

Here’s what you need to know about the 4 phases of the menstrual cycle…

Phase 1: Menstrual

When: Day 1-5 (ish) 

This is the beginning of your cycle, your period. Hormones (estrogen and progesterone) are at their lowest. Your uterus is shedding last month’s lining, which is why you’re bleeding. 

Because hormone levels are low, that drop can make you feel:

• More tired than usual
• Introspective or emotional
• Crampy or achy
• Socially selective

But here’s the underrated part: this phase is a reset. Low hormones can actually mean mental clarity for some people. You may feel reflective, honest, and less tolerant of nonsense. Anecdotally, watch the rom com and eat some dark chocolate.

Phase 2: Follicular 

When: Day 1–13 (starts during your period and continues after it ends)

Estrogen starts rising as your body prepares to release an egg. As your period wraps up, and estrogen climbs, so does your motivation. 

This is when you might suddenly feel:

• More energized
• Creative and idea-filled
• Curious and open to trying new things
• Socially optimistic

This is your “new month, new me” phase. You may feel more organized, more confident, and more capable of tackling projects. Biologically, your brain is responding to increasing estrogen, which can boost mood and cognitive flexibility. Translation: this is a great time to pitch ideas, start something new, or reorganize your entire closet at 11 p.m.

Phase 3: Ovulation

When: Around Day 13-15 (in a 28-day cycle — but everyone’s different)

Estrogen peaks, testosterone rises slightly. Ovulation is when you’re biologically most fertile, and when many people feel their best. 

You might notice:

• Higher confidence
• More social energy
• Increased libido
• Clearer skin
• Better communication skills

There’s real science behind the glow. Rising estrogen and a small bump in testosterone can boost mood and assertiveness. Some studies suggest people may even subconsciously dress differently or feel more attractive during this phase.

Phase 4: Luteal

When: Day 16-28 (after ovulation until your next period)

Progesterone rises to support a potential pregnancy. If pregnancy doesn’t occur, hormones drop. This phase is the longest — and often the most misunderstood. Right after ovulation, progesterone rises, which can make you feel calm and grounded at first. But if no pregnancy happens, estrogen and progesterone drop sharply toward the end of this phase. That hormonal dip? That’s where PMS can show up.

You might feel:

• Irritable
• Sensitive
• Anxious
• Bloated
• Extra hungry
• In need of alone time

PMS isn’t you being “dramatic.” It’s a real neurochemical shift. Hormone changes affect serotonin (your brain’s mood regulator), which can amplify emotions.

So… why do periods sync?

You’ve probably experienced it: you and your roommate get your period the same week. Your entire friend group suddenly needs tampons at the same time. The idea of “period syncing” (also called menstrual synchrony) became popular in the 1970s when a study suggested that women living together began to align their cycles over time.

The proposed explanation? Pheromones: subtle chemical signals that influence hormones.

More recent research has found little strong evidence that cycles truly sync because of pheromones. Many scientists believe what’s happening is actually math, not magic.

Here’s why:

• Cycles aren’t all exactly 28 days.
• Most range from 21–35 days.
• If two people spend enough time together, their cycles will naturally overlap sometimes.

In other words, if you and your best friend both have cycles that vary slightly month to month, they’ll occasionally line up purely by chance.That said, our bodies are influenced by stress, sleep, travel, and environment. Living together can affect those things, which can shift cycle timing indirectly.