Can Probiotics Change Your Period & Impact Your Menstrual Cycle?

Medically reviewed by Dr. Olusina Ajidahun, May 29, 2023
Probiotics can massively affect your overall well-being, from gut functions to immunity to sexual/reproductive health. Hence, if you are using a probiotic supplement, you are highly likely to observe its effects on your periods.
Contrary to the common belief, probiotics improve your menstrual health by regulating sex hormones, namely estrogen, and progesterone. Which in turn also affects the bleeding flow and menstruation pain.
- Probiotics can change the menstruation flow, pain intensity, and cycle duration.
- These microbes can increase or decrease the level of sex hormones.
- Probiotics are also useful for PCOS and Endometriosis treatment.
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Keep reading to find out how they alter the secretion of different sex hormones and what changes you may see in your period when taking these supplements;
How Can Probiotics Change Your Period?
Studies show that gut microbiota can affect the level of sex hormones in the blood. For instance, alteration in FSH and estrogen level changes the menstrual patterns and make your periods lighter or heavier.
Now, although scientists have recognized certain gut-hormone associations, the exact mechanisms are not yet understood.
However, case studies and social discussions on platforms like Reddit infer that probiotics can result in the following changes in your periods;
1. May Lighten Or Delay Your Periods
The effect of probiotics on menstruation timing and discharge is not scientifically evaluated, but Reddit threads like this report the tendency of probiotics to lighten and delay the probiotics.

This effect is likely associated with changes in estrogen levels due to probiotic supplementation, as described in the article’s next section.
2. May Reduce Menstruation Pain
Research shows that Lactobacillus strains can reduce menstruation pain and discomfort during periods.
According to this study, probiotic supplementation reduces the inflammation in uterine tissues and stimulates the immune system to prevent allergic reactions in the genital tract.
This translates to the breakdown of the lining of the uterus during menstruation is less painful.
3. May Help in PCOS Treatment
Probiotics can mediate the secretion and excretion of sex hormones by affecting the gut-brain axis or gut enzymes.
Recent research suggests that probiotics can help balance hormonal concentrations for treating PCOS.
It states the effects of Bifidobacterium lactis V9 on the regulation of sex hormone levels. (FSH and LH).
According to this journal, friendly bacteria produce gut-brain mediators that inhibit the secretion of FS and LH hormones in PCOS patients, preventing hyperactivity of ovaries and irregular menstruation.
The level of different sex hormones drastically changes at different stages of the menstrual cycle. A hormone having the peak concentration in one stage may be at its lowest level in the next stage.
Plus, sex hormones are strongly correlated to mood-controlling hormones and neurotransmitters.
This, helps relieve the stress associated with hormonal changes during ovulation and menstruation. And in turn, better stress management upregulates the menstrual cycle.
5. May Trigger PMS Symptoms In Hypersensitive People
While most women report positive changes in their periods with probiotics intake, some also experience negative effects.
These rare reactions are mostly reported by individuals hypersensitive to medications and allergens, especially histamine.
Probiotics can increase histamine levels which becomes trouble for people allergic to this amine compound.
Histamine intolerance can trigger and enhance Premenstrual syndrome (PMS) symptoms like anxiety, breast tenderness, headaches, fatigue, and muscle pain.
User Ok_Band2802 shared such an incident in her Reddit post.
Please note that she had a history of drug hypersensitivity.

So, when she took probiotics for gut and eyesight issues, she suffered from PMS symptoms.
Do Probiotics Cause Hormonal Imbalance?
Probiotics do not cause hormonal imbalance. Instead, the friendly bacteria can help maintain a healthy hormonal balance.
The menstrual pattern is mainly controlled by Estrogen, LH, Progesterone, and FSH hormones.
To maintain a hormonal balance, excess sex hormones are converted to inactive derivatives in the liver where they are broken down and excreted with feces.
However, many women have an increased amount of β- glucuronidase
Enzyme. This enzyme converts Estrogen back to its activated form.
As a result, the overall blood level of active Estrogen becomes high, inducing the formation of thick uterus tissues.
Such individuals usually have a heavy period and are predisposed to disorders like PCOS and endometriosis. Moreover, constantly high estrogen levels indicate hormonal imbalance (also known as estrogen dominance) and can also complicate pregnancy if not timely cured.
Recent studies suggest probiotics, especially Lactobacillus strains, decrease the amount of β- glucuronidase enzyme, ultimately lowering the estrogen level.
Low estrogen results in the growth of a thin uterus lining, so the bleeding is lightened.
Some women also experience a delay in menstruation. But this delay is likely a positive effect, and your cycle will soon return to the normal pattern.
A similar experience was shared by CarlyLouise, whose periods were delayed after starting probiotics.
Besides Estrogen, probiotics improve FSH levels (follicle-stimulating hormone). This hormone initiates the new menstrual cycle and causes ovulation (releases eggs from ovaries). Hence, a high FSH supports a good ovulation pattern in normal, healthy individuals.
However, a high FSH level in PCOS women can further aggravate the issue.
In such individuals, probiotics may trigger reverse action, decreasing FSH and LH levels – a total win-win!
(This process is discussed above for the B. lactis strain in the above section)
FAQs
Can Probiotics Cause Abnormal Bleeding?
Probiotic supplements can lighten bleeding, as reported by some users.
This effect is likely because of the prevention of excessive reactivation of Estrogen in the gut. This inhibition leads to low estrogen levels and lesser thickening of the uterus wall.
So, during menstruation, your body has a thin layer of flesh and blood to discharge.
Also, there’s no evidence that probiotics can increase bleeding during periods.
Can Probiotics Delay the Menstrual Cycle?
User discussions on the topic suggest that probiotics can delay the menstrual cycle, most probably due to their estrogen-lowering potential.
However, there’s no scientific evidence available yet to prove this effect.
Can Probiotics Make Your Period Longer?
No case study suggests that probiotics can make periods longer.
Can Probiotics Make Your Period Heavy?
No, probiotics won’t make you bleed heavily during periods.
Do Probiotics Shorten Periods?
No research or user experience shows that probiotics can affect the duration of menstruation. However, some ladies report having lighter periods after taking probiotic supplements.
Can I Stop Probiotics from Messing With My Periods?
You cannot stop probiotics from affecting your periods and hormonal levels.
But the good news is, in most cases, they do not affect the periods badly but help improve the hormonal balance and mood during menstruation.
However, probiotics may mess with periods if you are hypersensitive to histamines or similar drugs.
In this case, symptoms may be only by quitting the supplement.
Please discuss with your physician to find out if probiotics are causing the issue and what you can do about it.
Takeaways – Should you Try Probiotics to Improve your Cycle?
Though the effects of probiotics on the menstrual cycle are not completely understood, scientists and physicians are certain that probiotics improve the female reproductive cycle, mainly in 3 ways;
- They may help you manage stress effectively during your periods.
- They affect the balance between sex hormones like FSH and Estrogen.
- Last but not least, probiotics optimize your gut functions and keep GI issues like bloating, diarrhea, and constipation away during your periods.
That’s why I recommend you opt for a trusted probiotic supplement to improve your ovarian, uterine, vaginal, gut, and immune health.
Supplements like Gut+ from Yourbiology, Garden of Life For Women, and Culturelle Women’s Health are some of the most effective and uprated probiotics for women in the market.