Common Hormone Therapy Side Effects

Like any medication you may experience initial side effects with the hormones in Hormone Replacement Treatments (HRT). That said, most side effects will improve over time and settle. It is recommended to persevere with treatment for at least three months, and only then if things do not stabilise you should consult your doctor.

Possible Estrogen Side Effects:

  • Breast tenderness
  • Headaches
  • Indigestion
  • Nausea
  • Leg cramps
  • Vaginal bleeding

Possible Progestogen Side Effects:

  • Feeling Bloated
  • Breast tenderness
  • Depression
  • Mood changes
  • Acne
  • Vaginal bleeding

Potential Risks

HRT and Breast Cancer Risk

Although rare, there is a possibility for a small increase in one’s risk of breast cancer. This however does not translate into fatality due to taking HRT. Being on HRT may bring to light a process that may be underway already but is not believed to be a causative factor for cancer. So, it’ important to remember that this is a very common cancer: one in eight women in the UK will develop breast cancer, unrelated to HRT.

Interestingly, the risk is actually reduced in women who are on estrogen only HRT. It is observed that the slight increase in risk is possibly related to synthetic progestins in combined HRT. Hence use of micronised natural progesterone may be a better option as it is not believed to stimulate breast tissue. Irrespective of the fact whether one is on HRT or not, check your breasts regularly and have mammograms as per the national schedule.

It’s also important to remember that lifestyle measures such as quitting smoking, reducing alcohol intake, keeping one’s BMI under 30, maintaining a good diet, and exercising regularly, yoga and meditation go a long way in improving health and reducing the risk of cancer.

Risks of any treatment must always be measured against its benefits to quality of life and overall reduction of morbidity and mortality.

Risk of Thrombosis or DVT

There is no increase in risk of clots when HRT is used through the skin such as in gel, cream, or patch form. While there may be a minor increase in risk of DVT with oral or tablet preparations, it must be remembered that these risks have to be put into perspective as someone with high BMI of over 30 is already at a significantly increased risk of DVT which needs to be addressed first.

Benefits of HRT Patches

HRT patches and gels deliver hormones through the skin and directly into the bloodstream.
From here it goes to the target tissues. As they are not absorbed through the gut like oral
tablets they do not pass through the liver. It is in the liver that the clotting factors of the
blood are produced. As the hormones bypass the liver the risk of clots is not really affected.

Hence, when HRT is needed in women with high BMI or where there may be a concern
about clots then the transdermal route or through the skin is the preferred route.

Side Effects of HRT Patches

The only side effects associated with HRT patches per se are local in nature. In very rare circumstances, women may find that a particular patch causes them redness or irritation of the skin where it is applied. Some might find that they are hard to stay on especially if they are perspiring a lot. They do tend to leave a sticky mark when removed. The easiest way to remove is to use a little bit of lotion or cream and a dry flannel to rub it off with.
Other than this, any other side effects will be the same as other formulations of HRT i.e. that one may experience estrogenic or progestogenic side effects as described above.

Does HRT Cause Weight Gain?

HRT does not cause weight gain – women gain weight during menopause regardless of HRT. This is believed to be due to hormone imbalance. HRT may actually help restore metabolism and prevent weight gain and feeling of bloatedness.

Does HRT Cause Increased Risk of Stroke and Heart Attack?

If your background risk is low and you start HRT in your perimenopause and early menopause you actually reduce your risk of heart attacks. This is especially true of HRT patches, gels, and creams.

Forms of HRT

1. HRT Patches

These can be estrogen only or a combination of estrogen and progestogen. This kind of patch prescribed will depend on the regime the doctor is deciding for you.


Patches can be very discrete and only need to be applied twice a week, at most, and are
thus good for compliance. You do not have to remember to apply the patch every day unlike
taking a daily tablet.
Additionally the absorption is steady, giving a good blood level of hormone to optimise

As the hormone is absorbed through the skin it is particularly beneficial for reducing risk of
heart attacks and does not increase stroke risk. It also does not increase risk of deep vein
thrombosis (DVT).

As the hormone is absorbed through the skin it is particularly beneficial for reducing risk of heart attacks and does not increase stroke risk. It also does not increase risk of DVT or deep vein thrombosis.

Side Effects

There are no specific side effects of HRT patches. In rare circumstances some women notice
redness or experience irritation locally at the site of application. However, a different brand
of HRT patch may not cause that problem, and can be changed if issues persist.

2. HRT Tablets

There is a very slight increase in the risk of thrombosis or DVT, however if there are no pre-existing factors for thrombosis or DVT then the risk is very minor. Tablets are sometimes the preferred choice for women.

Sequential HRT

These are combination of estrogen and progestogen tablets given in a sequential pattern to women who are still menstruating during perimenopause or are in the first year since their last period. They are much milder than the combined pill, will aim to mimic your cycle, but are too weak to provide contraception.

Continuous Combined HRT

Here each tablet has a fixed dose of estrogen and progesterone and the aim is to not experience any bleeding. It can only be given to women who haven’t had a period in two years or more.

3. Estrogen Gels

These come in metered dose gel pump to apply on inside of the arms or thighs. The transdermal route allows direct absorption through the skin into the bloodstream and therefore there is no increase in risk of clots or thrombosis. It’s popular for women who may have suffered migraines on the pill for example can trial this route.

Estrogen Vaginal Creams

These come in very weak doses and are very helpful in reducing vaginal dryness, pain, and bladder symptoms. They are licensed for long term use twice a week.

Estrogen Vaginal Pessaries

These are like tiny pills that can be inserted into the vagina. They are very low dose and can be prescribed long term to help with vaginal dryness, painful sex, bladder problems, and dermatitis of the vulva.

Bioidentical Hormone Replacement Therapy (BHRT) Side Effects

As the entire range of hormones used in bioidentical hormone therapy is naturally derived
the likelihood of side effects may be smaller. This is related to the metabolic pathways that
hormones follow in the body. A healthy metabolic pathway leads to less chances of toxicity
and side effects.
It is important to remember that the rules for monitoring side effects whether mainstream
HRT or BHRT are the same.
Your clinician has to be experienced in the safe use of hormone balance therapy and be able
to choose hormones from either range that are most akin to those produced by our bodies.

Side effects, whether estrogenic or progestogenic, are the same and managed in a similar
fashion in both therapies. Hormones treatment must be treated with respect and should
always be supervised by a clinician.

For more information about Dr Meyer or if you’re interested in booking a consultation with her, visit or contact the clinic directly here.