Menstrual Cycle and Your Immunity - Nude Model Covering Herself in Pink Flowers

How Each Phase of the Menstrual Cycle Affects Your Immunity


For millennia, cultures have observed, documented, and worshiped the moon and its many faces, basing their belief systems, and predicting the future on the movements of celestial bodies across the sky. And while this notion that a ball of fire and far-away rock in the sky can predict or affect our physical realm is controversial to say the least, it cannot be disputed that sun and moon do influence our physical, mental, and behavioral changes on a 24-hour cycle.


This cycle, referred to as the circadian rhythm, regulates your sleep, hunger, cell regeneration, and hormone production. Yes, that includes your period. Any disruptions to these rhythms (like anxiety-induced insomnia, binging on Netflix until the wee hours of the morning, or going ham in the candy aisle) adds stress to your body as it tries to offset the adverse effects of running on two hours of sleep and Skittles.


We know you already know the importance of adequate sleep, proper hydration, and a balanced diet to keep your mind, body, and vagina healthy and happy, but there are side effects, if you will, linked to our menstrual cycle beyond our control that places extra pressure on our immune systems. 



The term menses is derived from the Latin word for month, which is a measurement of time based on the moon’s phases. 



Any time your muscles feel achy or you’ve got a case of the sniffles, check to see if you’re about to get your period. While the immune system and reproductive system aren’t directly connected these flu-like symptoms aren’t entirely coincidental. But the fluctuation of hormones plays a role well beyond your fertility and menstruation patterns. 


Think of your menstrual cycle as an additional vital sign, like your blood pressure, or pulse; it can let you know when everything is working as it should, when your body is going through changes, or when something is not as it should be.


Now, it’s important to note that neither your period, nor any other stage of your menstrual cycle is solely responsible for making you sick. But the inflammation associated with certain phases is related to your immune system in defense mode. Hello, cramps and bloating and headaches, oh my!


Inflammation anywhere in the body is a result of an activated immune system, but in this case, its origin may be more related to your body’s hormonal regulation than your lifestyle choices, or exposure to harmful bacteria or viruses. Understanding the phases of your menstrual cycle and how each affects your immune system can be helpful on your quest to overall wellness and determining whether or not what you’re experiencing requires an appointment with your doctor, or simply assuaging any concern after a late night of WebMDing.


Menstrual Cycle Length & Phases

The average cycle lasts anywhere between 24 and 38 days. Most of your cycles should fall within that range, but it’s totally normal for some to be longer or shorter than that. Age, genetics, and environment determine the baseline length of your menstrual cycle. Conditional and environmental effects include:

Diet & Exercise Food is fuel. Keep an eye on your sugar intake. Move your body. Don’t sweat it if you don’t sweat it out everyday. 

Dehydration Do we have to remind you again? Drink water, people!

Sleep schedule. Too little sleep doesn’t give your body time to heal and repair itself. 

Anxiety & Stress levels We could go into more detail, but it’d probably stress us out. 

Hormonal birth control or prescription medications. Hormonal birth control (HBC) always contains a synthetic progesterone (called progestin) and sometimes contains estrogen, depending on the type. HBC works by keeping your levels of sex hormones high, which prevents ovulation and/or thickens cervical mucus. Some evidence suggests that HBC (particularly progestin-only forms) may down-regulate your immune system, which increases risk of infection. If this doesn't make much sense now, keep reading!

Between these 24 to 38 days, your body moves through four stages called the menstrual, follicular, ovulatory, and luteal phases. Each of these phases provide your body with varying levels of estrogen, progesterone, and testosterone—the hormones that play a role well beyond your fertility and menstruation patterns. 



PHASE 1 Menstruation


🌑  Lasts on average 3 to 7 days

⬇  Lowered Immunity


When you’re actually menstruating, your levels of estrogen and progesterone are low. They’ve already done the hard work of thickening your uterine lining in preparation for possible pregnancy, and can now rest.


Menstruation itself is linked to increased inflammation, although scientists aren’t exactly sure why. One possible answer for a lowered immune system response is that the inflammation, especially associated with cramps and bloating, can worsen symptoms of chronic health conditions like asthma or arthritis. Your immune cells will function at a lower level as your system struggles to fight off any bacteria or virus you might come in contact with during this time. 

Another piece of the puzzle is stress related. Surprise, surprise. Stress, anxiety, mood swings, and the like are all common symptoms while you’re menstruating —whether it’s body related or body-image related, this stress elevates cortisol levels, which can weaken your immunity. 


PHASE 2 The Follicular Phase  

🌗  Day +/- 3 to 14

⬆ Increased immunity (but with a caveat)


Once your body is done menstruating, it enters the follicular phase where your ovaries are preparing an egg to be released while your uterus lining thickens in preparation for a possible pregnancy. Your estrogen levels are rising a few days before ovulation, making you feel full of energy and you may find that your sexual desire increases, along with vaginal discharge. People also tend to have higher levels of antibodies in their body and have an increased inflammatory response, making those in the follicular phase less susceptible to infection. 

In theory, your body functions this way to promote pregnancy. When you’re in the early to mid-follicular phase of your cycle, the chance of getting pregnant is extremely unlikely, since you haven’t ovulated, or released an egg yet. During this time, your body wants to fight off any foreign invaders so that you'll be healthy enough to become pregnant. 

But while your immune system has a heightened response to outside invaders, it may also have the same heightened immune response to your body's own cells and end up attacking itself. That’s why people with high levels of estrogen are more prone to autoimmune disorders, chronic illness, or developing certain types of cancer. 


PHASE 3 Ovulation 

🌕  Day 13 to 16
⬇  Lowered immunity


During the third phase of menstruation, there are several days when your body is primed for pregnancy. During ovulation, one of your ovaries releases an egg in preparation for a potential pregnancy and your estrogen levels dip, along with your immunity.  Research suggests that this lowered immune response might happen to allow outside cells (aka sperm) into the body. Basically, your hormones are telling your immune cells not to attack a possibly fertilized egg. 

While the evidence remains inconclusive, people who menstruate may be more likely to experience infections mid-cycle, so take extra care to get enough rest, water, and probiotic-rich foods to optimize your vaginal health and wellbeing. 


PHASE 4 The Luteal Phase  

🌒  Days 15 to 28
⬇  Lowered immunity

The premenstrual, or luteal phase, is the week or so leading up to your period. During the luteal phase, your body prepares itself for the stress of menstruation, which often manifests in cold and flu-like symptoms. 

The reproductive hormone progesterone rises during this fourth phase, and is known to make you moodier or more anxious. Given that stress hormone cortisol is linked to inflammation, your immune system is also feeling stressed by having to work harder to stay healthy. 

More progesterone lowers your body’s ability to fight infections that can affect reproductive, gastrointestinal, and respiratory tracts. These PMS (premenstrual syndrome) symptoms often impact your energy, mood, and body image, along with the following symptoms often mistaken for a cold or flu.


Common PMS Symptoms That Mimic the Flu

  • body aches
  • runny nose
  • sore throat  
  • extreme fatigue
  • dizziness
  • nausea 
  • vomiting 
  • loss of appetite
  • sensitivity to light



Track Your Cycle & Manage Symptoms

We know how frustrating these symptoms can be, but know you're not alone — and this phase won't last forever (even if it feels like it). It’s always a good idea to track your menstrual cycle and symptoms. Whether it’s in a bullet journal or an app, you’ll begin to notice patterns that are unique to your body, which can help you determine if that “off” feeling is due to your upcoming period, or if you’re coming down with something more serious. 

If you’re experiencing persistent symptoms that are significantly impacting your daily life, or find that your period is debilitating, that may be a sign of a bigger problem.  We want to reiterate that you know your body best, and you shouldn’t hesitate to schedule an appointment with your doctor.


Probiotic Jar on White Background

Protect & Promote a Healthy Microbiome 

Our clinically proven Probiotic is deliberately formulated to protect, promote, and maintain a healthy gut, immune system, and vaginal microbiome. 





Tonic Bottle on White Background


Soothe & Soak

A warm bath soak infused with Tonic's soothing essential oils are known to increase blood flow to help ease digestive and pelvic pain discomfort. 







Struggling with symptoms but not sure what you need? Take our quick quiz for personalized product recommendations. Take the quiz





Related Reading

Decode Your Vaginal Discharge

Learn What Your Period Blood Is Telling You About Your Health 

Top 5 Foods that Balance Your Gut & Support Vaginal Health

Everything You Need to Know About Yeast Infections

Three Must Reads on Bacterial Vaginosis



Back to blog

Leave a comment

Please note, comments need to be approved before they are published.