There is currently not a lot of agreement among hormone experts about cycling your hormones as part of HRT. While estrogen is typically not cycled (but it can be), there are many experts who believe that at least progesterone should be cycled.
So what’s best for you?
The truth is that some women will do better with a more nuanced and cycled approach and some will be fine without. Assuming your dosage is safe and adequate for your goals (symptom relief and/or longevity and risk reduction), then cycling will largely come down to what is best for you, your lifestyle and your provider’s willingness to be flexible with you.
Cyclical vs. Continuous HRT
Cyclical HRT (AKA Sequential HRT)
You take estrogen alone for a period of time, then add progesterone later in the cycle (typically on day 14 of your cycle or of the month if you are not cycling). This is truly a sequential HRT approach, though it is commonly referred to as cyclical HRT.
A more nuanced approach is to cycle progesterone two weeks on and two weeks off in addition to adjusting estrogen dosages throughout the month.
Continuous Combined HRT
You take estrogen and progesterone every day, at the same dosage. This is by far the most common approach to HRT currently.
Why Some Experts Recommend Cyclical HRT
Both estrogen and progesterone can be cycled and varied throughout the month in effort to create physiology closer to what we had when we were cycling monthly on our own, which looks like this:
- Week 1: Lowest levels of both estrogen and progesterone. During a bleed and through day 3-5, estrogen will be at its lowest and progesterone is near zero. Estrogen will begin to rise by the end of week 1 (progesterone will not rise until after ovulation).
- Week 2: Rising estrogen during week 2 leading up to a larger spike in estrogen at ovulation.
- Week 3: Progesterone rises and estrogen, while lower than week 2, doesn’t disappear entirely and gets a little bump up again around day 19-21.
- Week 4: Both estrogen and progesterone fall during week 4 leading to those very low levels of week one, inducing a bleed.
Cycling estrogen is much easier with a topical cream or gel formula vs. cutting up patches and varying the dosages that way, but I’ve seen it done. Progesterone on the other hand is much easier to cycle and is more often cycled than estrogen. While some women take the same dosage of both hormones throughout the month, others do better when they cycle at least progesterone and some do best cycling both estrogen and progesterone.
Rationale For Cycling Estrogen
Estrogen is a stimulator of various growth factors in our bodies. As such it grows the lining of the uterus but it also stimulates breast tissue, new bone growth and neurological repair as well. Our bodies are constantly undergoing remodeling and clearing out older cells so newer ones can occupy their space and estrogen supports this systemwide, throughout your whole body – even though we often think of estrogen as just related to the uterus or the breasts. Cycling your HRT allows these natural ups and downs of estrogen to take place, thus giving more time and space for both growth and remodeling and repair.
It should also be noted that many, many women on HRT are not getting high enough doses of estrogen to warrant cycling their estrogen. If you are using higher doses, more inline with the level of hormone your ovaries were producing in your 20s and 30s, cycling should be more of a consideration.
Rationale For Cycling Progesterone
Looking at the map of the cycle above it’s clear that our bodies see some amount of estrogen throughout the month although the amounts are very different, for example week 2 vs. week 4.
With progesterone being a product of ovulation, we are only exposed to it for two weeks-ish out of the month. Progesterone release starts at ovulation and rises like a bell curve peaking about a week later and then ideally tapers back down (vs. quickly dropping off) by the end of the cycle, signaling the next bleed.
So yes: cycling progesterone is the more natural way or more closely mimics our body’s normal rhythms but it is more than simply intuitive sense behind the strategy of cycling progesterone.
We know that progesterone will cause some degree of downregulation of estrogen receptors so a break from progesterone can help estrogen work better during the first two weeks of the month/cycle. Many women notice their low estrogen symptoms improve or they generally feel better when they begin cycling their progesterone vs. taking it daily. This is of note becuase often when women feel their low estrogen sytmpoms creep up they are often just bumped up in dose without considering the interplay with daily progesterone.
Cyclical HRT: Is It Worth The Hassle?
The dance estrogen and progesterone do throughout the month is nothing short of beautiful, with the rise and fall of each hormone allowing the other to do its job more fully. The merit of continuing to use HRT in this rhythmic fashion allows a woman to experience more benefit from each hormone and often with less side effects.
As far as prevention, it’s important to remember that estrogen is all about stimulating growth and progesterone tempers that stimulation keeping estrogen in check. This balancing effect will help avoid common side effects of too much estrogen like water retention, sore breasts, mood issues, breakouts and heavier bleeding as well as allowing estrogen to act to her fullest benefit when she has her two weeks to shine without progesterone.
An example of progesterone keeping estrogen in check is certain tumor suppressor genes are turned on by progesterone and turned off by estrogen. Proper expression of these genes is supported by pulses in progesterone and this can play a role in certain types of cancers.
More on cancer risk and HRT in this article.
As well, we would normally have a pause from both hormones at least to a large degree (estrogen still remains at low levels, while progesterone drops to nearly zero) every 4 weeks as well. During those first 5-7 days of the cycle we are very low on both estrogen and progesterone. This break from higher levels of these hormones gives our receptors a chance to reboot and be protected from constantly being turned on by a hormone. Many women report that when they cycle their hormones they overall experience more benefit from their HRT.
This pause in both estrogen and progesterone is a time when we focus less on growth and more on clearing out dead or senolytic cells.
Senolytic cells are often called zombie cells as they are not functioning optimally but are not fully dead, so they steal resources from neighboring, healthier cells. I liken this to needing to prune a shrub in your garden: when you pull off the dead or nearly dead branches the plant starts to thrive again as now all resources are available for the healthier, newer growth. There’s a time for stimulation and growth, but we also need a time of repair and rest.
This clean up of cells happens in the uterine lining and it’s thus shed, but it also happens in breast tissue, bone and brain – the tissues we so often associate with needing estrogen support. So you can see the cyclical nature of our hormones over a 4 week or so cycle turns out to have a lot of impacts on multiple tissues and it is over simplistic to say these rhythms of hormones are preferred by more alternative providers who simply focus on things being “more natural”.
The timed nature of our cyclical hormones has body wide advantages. Research shows that when HRT follows the more classic rhythm of hormones there is an enhanced impact on beta-amyloid levels (which is linked to Alzheimer’s disease) by estrogen, women experience less HRT related side effects like mood swings, weight gain and breast tenderness) and there may be an enhanced benefit on inflammation and heart health by estrogen.
What Happens When You Cycle HRT?
If you cycle your HRT, with two weeks on progesterone and two weeks off you likely will still get a bleed every 4 weeks. This will often continue long into menopause as long as you continue to cycle the hormones.
Many women find this alarming but it’s just as normal as when their own ovaries were timing these hormone expressions. Unless the bleeding is heavy or contains large clots, it’s simply a shedding of the uterine lining built up in response to estrogen’s stimulation. Certainly if bleeding changes or becomes heavier it’s important to reconsider dosages of estrogen and progesterone and potentially indicating a need for an ultrasound and posibly also a biopsy.
Advantages Of Not Cycling HRT
You won’t likely get a bleed and many women love not having to worry about that anymore. In fact, some women start HRT with the goal of stopping their periods – seeing it as a quality of life thing to just be done with it. HRT in this situation is often doses at the lowest dose to alleviate symptoms and often for the shortest duration of time are what’s used.
Many experts agree that some level of hormone support is better than none so if alleviation of symptoms at the lowest dose possible for the shortest time and avoiding having a bleed makes more sense for you, then cycling your HRT might not be the right fit.
It’s way less work for you. Especially during menopause when you’re through perimenopause and your period fully stops, you can take estrogen and progesterone at the same doses throughout the month, day after day and no longer worry about when to take which hormone or when you will be bleeding.
It may also be more expensive if you have to pay for various dosages that can create problems for insurance and if you use compounded hormones (which many do if cycling estrogen) that is often an out of pocket cost.
You may sleep better taking progesterone daily vs. cycling it on and off. Some women simply need that progesterone to get a good night’s sleep and when they go two weeks on and two weeks off they do not sleep as well for half the month and that’s not great either.
What’s Best For You?
If you are trying to honor the hormone rhythms of our younger years and often want a higher level of hormone to not only alleviate symptoms but to optimize function and vitality and enhance the protective benefit of HRT then discuss cycling hormones with your provider.
As well, if you feel you are constantly having to increase your dose, consider a cyclical approach as the balance of estrogen and progesterone is generally better with sequential use of hormones.
Like so much of women’s health and certainly with HRT, a customized approach that takes into account your symptoms, goals, risk factors and preferences over any one set protocol is the ideal so be sure your provider is willing to have these nuanced discussions and help you find the regimen that is best for you.