Hair and hormones: The ultimate guide

Together, we’ll address common hormonal hair care questions such as “which hormone causes hair thinning?” and “What lifestyle changes can I make to improve hair health?”.We’ll also discuss the most common ways in which hormonal changes through your life affect your hair, including changes during the menstrual cycle, hormonal birth control, pregnancy, postpartum, and perimenopause.

How hormones affect hair growth

First things first, what exactly are hormones, and why are they messing with your beauty regimen? Hormones are naturally occurring chemicals in the body that regulate many of your major internal systems and functions. You can think of them as messengers that travel through your bloodstream with instructions telling your organs and tissues what to do, how to do it, and when. They play a huge role in maintaining a healthy body, but they can also cause some less-than-desirable effects when they’re out of balance [1].

Hair growth basics

Before we dive into the causes of hair thinning with our experts, let’s take a step back and look at the basics. While hormone fluctuations can lead to many different issues in the body, hair growth and hair thinning patterns are one of the most noticeable. To understand which hormone causes hair thinning, we’ll need to understand the science behind the hair growth cycle first.

The hair growth cycle can be influenced by everything from stress to metabolic function to nutrition and hormones. The hair growth cycle is as follows:

1. Anagen phase: This is when individual hairs actively grow and produce strong, thick strands. Typically, this phase lasts 2–7 years, and the presence of the hormone estrogen helps to prolong this phase. At any given time, up to 90% of your hair is in the anagen phase.
2. Catagen phase: This short transitional phase lasts about two to three weeks. During this time, the hair follicle starts to shrink and stops producing new hair, preparing the follicle for rest.
3. Telogen phase: This phase lasts for about two to three months, and it’s when the follicle is inactive and resting. This means that it’s holding the hair in place until it naturally sheds. 
4. Exogen phase: During this phase, newly developing hair within the follicle grows upward, pushing the old hair out and resulting in both shedding and the beginning of a new anagen phase.

[2]

Which hormones cause changes to the hair?

Throughout our lives, different hormones can play a different role in our hair health. To answer the question of which hormone causes hair thinning, let’s dive a little deeper into how each of these hormones can affect the normal cyclical hair growth pattern:

• Cortisol: High stress means elevated levels of cortisol, the primary stress hormone in the body. When elevated for long periods, cortisol can affect the cells that build the hair and keep follicles stuck in the resting/shedding phase longer [2].
• Androgens: Increased levels of androgen hormones like testosterone and the more potent dihydrotestosterone (DHT) can shrink hair follicles over time, which may lead to weaker hair strands and an overall pattern of thinning [3]. Even though androgens are usually classified as “male” sex hormones (because men typically have higher levels of them), everyone has androgens present in their body (just like males have low levels of estrogen and progesterone, too) [4].
• Estrogen: Estrogen’s function when it comes to hair is to keep it in the anagen phase, which means that if there is more estrogen present in the body (as there is during pregnancy), your hair will likely grow longer and thicker. It also balances androgen levels in the body, further delaying the catagen and telogen phases [2].
• Progesterone: Progesterone also plays more of a protective role in maintaining the anagen phase by lowering the amount of DHT produced. A drop in progesterone such as at an event like childbirth or during perimenopause can cause hair to shift into the shedding phase. .[3]
• Thyroid hormones: Hormones that regulate thyroid function (called T3 and T4) also influence hair growth phases. They can even influence hair structure and pigmentation as well [5]. 

Of course, your first port of call if you’re concerned about your hormonal health should be your doctor’s office. Dr. Anjali talks us through the specifics. “I recommend seeing your doctor to discuss testing your hormone levels (ex. Estradiol, Progesterone, LH, FSH, Prolactin, Testosterone, DHT, DHEA, Thyroid panel, Cortisol).” 

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We've partnered with trusted hair growth supplement brand Nutrafol to bring you this expert guidance on hair and hormones. While learning about how hormone health impacts hair, first-time subscribers can also receive 20% off a 3-month subscription (or 25% off a 6-month subscription) to Nutrafol's supplement ranges that cater to all women at all walks of life*.

How hair changes throughout the menstrual cycle

Now that we’ve established that hair follicles respond to fluctuating hormones, you may be wondering if the fluctuations that happen during the monthly menstrual cycle can affect your hair. Many people seem to experience “bad hair days” around the time of their period, and although scientific research has yet to confirm large-scale evidence of this phenomenon, there are some potential explanations [6].

It’s normal to notice changes to your hair in the luteal phase (after ovulation). Many women report that their hair can feel more greasy in the lead-up to their periods. One short-term study confirms this, finding that women with excess oil production on the scalp generally had the highest levels of oil in the week before menstruation (during the luteal phase). But this same study did not find any differences in women with lower scalp oil levels, and only tracked participants for three consecutive cycles [7].

Aside from that finding, there is more evidence to suggest that shifting hormones throughout the menstrual cycle can have a direct effect on the way we feel about our self-image. Studies have shown that women tend to have lower levels of body satisfaction and perceived self-attractiveness during the luteal phase specifically [8]. In other words, we tend to be much harder on ourselves during the latter half of our cycle. 

So while hormones do play a role in our self-image, and that can be confusing and frustrating to navigate, the fact remains that there is limited evidence to suggest that hair quality changes throughout the menstrual cycle. 

As ever, if you have questions or concerns, it’s worth taking your concerns to your healthcare professional for further investigation. “Depending on your menstrual cycle history, your doctor may want to test specific hormones on a specific day of your cycle to better understand your patterns,” says Dr. Anjali.

Hair changes in pregnancy

If you’ve recently become pregnant, you may be wondering if hair changes are on the horizon for you during this new stage of life. The short answer is yes — many women report thicker, fuller hair during pregnancy, and it’s just one of the effects that contributes to the legendary “pregnancy glow.” Though this may not happen for everyone, increased estrogen during pregnancy typically leads to hair growth [9].

Alternatively, you may be feeling more stress during pregnancy, leading to increased cortisol. As we outlined above, cortisol and other stress hormones can contribute to hair thinning and shedding. Either way, whether you’re experiencing thicker hair or hair thinning during pregnancy, your hair growth cycle should rebalance in a few months after giving birth once your hormones have returned to their previous levels [9]. 

Talk to your healthcare provider and/or care team if you’re concerned about the effects of pregnancy hormones on your hair quality, and remember that you can always seamlessly switch from NC° Birth Control to NC° Plan Pregnancy and NC° Follow Pregnancy for extra support along your fertility journey.

Please note that Nutrafol Hair Growth Nutraceauticals should not be taken during pregnancy.

Hormonal hair thinning postpartum

Natural Cycles also supports you after childbirth with NC° Postpartum. After giving birth, it’s common to notice more hair falling out. In fact, one study found that over 90% of women experience postpartum hair shedding [10]. While it can be an uncomfortable and distressing postpartum symptom, it’s a natural part of the recovery experience, and shouldn’t lead to any permanent hair loss or bald spots [9].

Dr. Woolery-Lloyd confirms “Hair thinning that correlates with hormonal life stage changes can also point to hormonal hair thinning. Specifically, this type of hair thinning can be seen postpartum...”

As for the timeline, shedding may peak around four months postpartum, but it should resolve within about a year after childbirth once your hormones return to pre-pregnancy levels [11]. 

Hair thinning in perimenopause

You may also experience several kinds of hair changes as part of the perimenopause transition (the life stage leading up to menopause, which is the last menstrual period in a woman’s life). Some of the most common hormonal hair thinning you’ll see in perimenopause includes:

• Increased shedding overall
• Changes in texture, becoming more dry and brittle
• More sparsity around the crown and hairline
• More scalp visibility overall [3]

Dr. Woolery-Lloyd explains what’s happening behind the scenes: “During perimenopause, estrogen and progesterone levels drop, which disrupts the hair growth cycle. Estrogen normally helps prolong the anagen (growth) phase of hair follicles, so when its levels decline, the anagen phase shortens.” She adds that, “This means hair spends less time growing and more follicles enter the resting (telogen) or shedding (catagen) phases sooner. The result is overall thinning and increased hair shedding.”

While this is the general experience of many perimenopausal women, it's important to remember that your experience may be different, as everyone’s perimenopause journey is unique. It’s also sometimes difficult to discern which of these hair effects stem directly from hormonal shifts during perimenopause or are simply a natural part of aging.

Regardless, these symptoms can be tough to deal with mentally and emotionally. If you’re experiencing perimenopausal symptoms such as hair thinning, fatigue, weight gain, or joint pain that are interfering with your everyday life or affecting your well-being, talk to your healthcare professional for advice and treatment options.

Perimenopause is an impactful life stage and looks different for everyone. Changes to our bodies, with new symptoms emerging is not unusual. But that doesn't mean there aren’t steps you can take to support your journey.

Dr. Anjali says, “One common myth I hear often is that the thinning and shedding that many women experience during perimenopause is permanent and that they’ll never have healthy hair again. This leaves so many women feeling hopeless and it’s just not true.” 

One of those ways to address hair thinning in perimenopause is with Nutrafol’s Women’s Balance Hair Growth Nutraceutical. It’s designed with women aged 45+ in mind, and the formula has been clinically proven to support hair growth and hair quality for women during this life stage.

Hair changes and hormonal conditions

Aside from the hormonal shifts that happen throughout different life stages, some people also experience hormonally-driven conditions like PCOS, endometriosis, and certain thyroid conditions.The associated hormonal imbalances can affect your hair growth patterns and overall hair quality [12,13,14]. 

If you think your hair thinning may be related to a hormonally-driven condition, consult with your healthcare professional for guidance and treatment.

Steps to promote healthy hair and manage hair thinning

Overall, hormonal hair thinning can happen for a variety of reasons over the course of our lives, and although there isn’t much we can do to change our genetics or certain life circumstances, Dr Anjali believes there’s a lot to be learned from testing and tracking our own biometrics. 

“Tracking and testing your hormone patterns is one of the first things I recommend to anyone who wants to better understand how their hormones may be influencing their hair health,” says Dr Anjali. “For example, you can track your basal body temperature and make a note of when in your menstrual cycle you notice more shedding. This can clue you into which hormones may need extra support, and you can take specific steps to address them.”

We want to underscore that the best way to address any kind of hair thinning is by seeing a specialist — like a dermatologist, an endocrinologist, or your primary healthcare provider — to assess root causes and address that cause specifically. But once you’ve gotten that assessment, here are some additional lifestyle suggestions to discuss with your provider.

Maintain scalp health

Promoting healthy hair requires maintaining a healthy scalp. Keeping your scalp clean with regular, gentle cleansing and scalp massages can support the healthy functioning of those follicles, and create a better ecosystem for hair growth overall [15]. 

Dr. Woolery-Lloyd advises, “A healthy scalp is important for strong hair follicles. Gentle cleansing, scalp massages, and treatments that help exfoliate the scalp create a better environment for hair growth.”

It’s worth knowing then, that building scalp care into your haircare routine could be a valuable tool to also promote hair health.

Support hormonal balance with lifestyle and dietary changes

Of course, how we treat our hair can also affect its health. "Avoid excessive heat styling, harsh chemicals, and tight hairstyles that stress hair. Stress management strategies like exercise and meditation may help minimize hair thinning influenced by stress,” advises Dr. Woolery-Lloyd. It makes sense then, that a simple lifestyle change, like air drying your hair can make a difference to its overall health.

But not all lifestyle changes are as obvious. As we established early on in this article, hormonal hair thinning is often due to an excess or lack of certain hormones. To keep your hormones in balance as best you can, Nutrafol’s Expert Team recommends consuming a nutritious diet, getting quality sleep each night, exercising regularly, minimizing alcohol and tobacco use, and managing stress where possible (we know — this is easier said than done). 

Make sure your diet contains essential nutrients, such as iron, Omega 3s, vitamin D, and Zinc. Alternatively, taking these as supplements you’ll find over-the-counter can make a difference in your hormone health. Just remember to consult with your healthcare provider before starting any new regimen (we can’t recommend that enough), as getting too much of certain nutrients can actually contribute to hair thinning [2,15].

Curious to try an alternative option to address hair thinning? Nutrafol is the number one dermatologist-recommended hair growth supplement brand according to IQVIA ProVoice survey for 12 months ending March 31, 2025. Nutrafol uses science-backed ingredients, proven with rigorous clinical testing, to create various supplement formulas tailored to your life stage and lifestyle. 

Take the Nutrafol hair wellness quiz to see what factors may be affecting your hair at this time, and how Nutrafol can support you through any kind of hormonal hair thinning.

Get hormonal hair thinning support with Nutrafol x Natural Cycles°

Thanks for reading up on the relationship between hair and hormones. Our bodies, hormones, genetics, lifestyles, and circumstances are exceptionally unique — and all of these can affect our hair. That’s why it’s helpful to have tools on hand like Natural Cycles and Nutrafol that meet you where you are, whether that’s getting pregnant, postpartum, or through perimenopause and beyond.

Nutrafol supplements are not recommended while pregnant or trying to conceive. However, the OBGYN-developed Nutrafol Postpartum product contains ingredients that are breastfeeding-friendly.

At Natural Cycles, we’re dedicated to destigmatizing these conversations and closing the knowledge gap on women’s health to allow you to live confidently. Our FDA-cleared app offers individual hormonal support at any stage of life. Why not find out if Natural Cycles could work for you today?

*Terms & Conditions: 

Valid only on the first delivery of a new Nutraceutical subscription created on nutrafol.com by 12/31/25 at 11:59pm PST. Nutraceutical subscription renews every 90 days at $224 or every 180 days at $422. Max one offer per customer; cannot be combined with any other offers or sales.