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Does Letrozole cause weight gain?

When it comes to fertility drugs, there are a lot of misconceptions and myths floating around. One of the most common is that Letrozole causes weight gain. In this blog post, we will dispel that myth and give you the facts about Letrozole and weight gain. Keep reading to learn more!


If you have a certain sort of breast cancer, your doctor may recommend Femara (Letrozole) as a treatment option.

Femara is a chemotherapy drug given to postmenopausal women. It’s used to treat the following types of cancer:

  • early breast cancer
  • metastatic breast cancer
  • advanced breast cancer
  • breast cancer that’s hormone receptor-positive (HR+) or the HR status is not yet known (it hasn’t been tested for yet)

Femara is a tablet that you chew once per day. It’s designed to be used as a long-term therapy.

For more information about Femara, including information regarding the types of breast cancer it cures, see this in-depth article on the drug.

The most frequent adverse effects of Femara are back, joint, and abdominal pain. Other common side effects include mouth sores, nausea/vomiting, fatigue (especially in women), flushing or sunburn-like skin discoloration, mood swings/depression. There have been several reported cases of allergic reactions following injections with the drug

What are the more common side effects of Femara?

Some people may experience minor or severe adverse effects while taking Femara. The following are examples of some of the most commonly reported side effects with Femara:

  • hot flashes
  • bone, muscle, or joint pain
  • flushing
  • swelling, usually in your hands, arms, feet, or legs
  • headache
  • fatigue (lack of energy)*
  • dizziness
  • sweating more than usual

What are the mild side effects of Femara?

The majority of side effects associated with Femara are minor. The following are some examples of low-dose Femara’s less serious adverse effects:

  • hot flashes
  • bone, muscle, or joint pain
  • flushing
  • swelling, usually in your hands, arms, feet, or legs
  • headache
  • fatigue (lack of energy)*
  • dizziness
  • sweating more than usual
  • weight gain*
  • feeling extremely tired
  • hair loss*

In most situations, these adverse effects should be brief. And some are simple to handle as well. If you have any symptoms that are persistent or bother you, talk to your doctor or pharmacist right away. And don’t stop taking Femara unless your doctor tells you to do so.

Other than the ones mentioned above, Femara can cause minor adverse effects. For more information, see the manufacturer’s package insert.

Note: After the Food and Drug Administration (FDA) has given a drug the green light, it keeps track of any negative effects. Visit MedWatch to notify the FDA about a side effect you’ve experienced with Femara.

Precautions for Femara

Before taking Femara, talk to your doctor about your health history. If you have any medical issues or other factors that impact your health, this medication may not be suitable for you. The following are some of the conditions and elements to consider:

High cholesterol

Femara has the potential to raise cholesterol levels. Your doctor will almost certainly prescribe cholesterol tests while you’re taking the medicine due to the danger of this adverse effect. If your cholesterol levels get excessively high, your doctor may prescribe cholesterol-lowering medicines.


Tell your doctor if you have osteoporosis before starting Femara (brittle, fragile bones). Taking Femara has the potential to decrease bone density. Osteoporosis can develop or get worse as a result of this. Low bone density can also lead to fractures of the bones. You may be more susceptible to low bone density if you already have osteoporosis before taking Femara.

If you have osteoporosis, your doctor may prescribe medication to help safeguard your bones during Femara therapy. During the treatment, they will probably check your bone mineral density as well.

Severe liver problems

Your liver aids in the removal of Femara from your body. If you have severe liver issues such as cirrhosis (liver scarring), your doctor may prescribe a lower dose of Femara. Before starting Femara, inform your doctor if you have severe liver problems.

Allergic reaction

You shouldn’t use Femara if you’ve had a negative reaction to it or any of its components in the past. Discuss with your doctor what other therapies are best suited for you.


You should not take Femara while pregnant. For additional information, see the “Pregnancy and breastfeeding while taking Femara” section below.


You should wait at least three weeks after your last dose of Femara before breastfeeding or becoming pregnant. For additional information, see “Femara and pregnancy” below.

Weight Gain from Letrozole

Letrozole, an Aromatase Inhibitor, has the potential to cause weight gain. “Will Letrozole make me gain weight?” is one of the most frequently asked questions we receive in our support groups. Every person is different when it comes to these endocrine therapies. However, in today’s post, we’ll look at the most prevalent causes of weight changes and offer some strategies for fighting against unwanted cushioning as a result of this estrogen deficiency.

After a breast cancer diagnosis and treatment, many individuals gain weight. Lifestyle modifications that usually accompany a breast cancer diagnosis are often to blame for the weight increase.

You may also become fatigued for a number of reasons, including sickness or other health issues such as psychological stress. If you are taking prescription drugs, it is possible that your doses have changed, which can lead to increased tiredness and less physical exercise. It’s also possible that you’re eating too many meals and snacks during this time because of the financial strain caused by treatment. You may lose weight for various causes, such as owing to an injury or sickness (such as cancer).

According to the Women’s Healthy Eating and Living (WHEL) study, 65 percent of chemotherapy patients were more likely to put on a few pounds. Women on average weigh 2-5 kg (about 4-11 lbs). But that is not the time to be concerned about weight gain or start a new diet regimen. Keep in mind that you are going through cancer treatment, which means it is important to care for yourself!

If your breast cancer is hormone receptor-positive, which means that the cells have estrogen or progesterone receptors, you are more than likely going to be advised to take endocrine therapy as part of your longer-term treatment plan. Endocrine therapy, also known as hormonal therapy, is used to reduce estrogen levels or stop the estrogen receptor from working. Your oncologist may recommend Tamoxifen (Aromatase Inhibitors) in some situations.

The aim of hormonal therapy is to minimize the chance of breast cancer recurring or progressing. This is one of the drug’s primary benefits! However, when we consider the quality of life and survivorship/thrivers, we must also consider the impact estrogen deprivation has on general health. We know that these aromatase inhibitors can cause osteoporosis, increase cardiac problems, and induce diabetes. Is it also linked to weight gain?

It’s simple to assume that weight gain is related to less activity, a slowing metabolism with age, or poor food choices. Whatever the case may be, it appears that those being treated for breast cancer who are on endocrine therapies acquire weight, regardless of their physical activity and healthful conscious and nutritional selections.

The impact Letrozole has on lipid metabolism is one matter that very seldom gets discussed (and more study is certainly needed). While there have been a few trials and research conducted into the influence aromatase inhibitors have on the lipid profile, results have been inconclusive. What we do know is that these AI’s can disrupt blood levels.

For example, high total cholesterol, LDL (the “bad” cholesterol) and HDL (the “good” cholesterol) increase the risk of heart disease. We also know that lipoprotein lipase (LPL), which is regulated by insulin, removes fat from the circulation and puts it into the cell. If this enzyme is present in a muscular cell, it will transform the fat into energy.

If the enzyme is located on a fat cell, it will encourage the cell to get fatter by drawing fat into it. Estrogen inhibits LDL and, with lower estrogen levels in women’s bodies, this might be one cause of menopause weight gain or during breast cancer therapy.

There are several reasons why people might put on weight when they are undergoing chemotherapy or hormonal therapies. Some of these biological side effects are beyond one’s control. However, there are things you can do to maintain a healthy weight.

Our behavior is controlled by our decisions, such as what foods we consume and how active we are. Here are some of our favorite ideas! This list isn’t complete, so feel free to pick whatever you like. It’s crucial to set modest, achievable objectives in the beginning. We’re here for the long haul!

  • Unprocessed and nutrient-dense foods should be your aim.
  • Reduce your consumption of added sugar by eating a low-sugar diet.
  • Avoid alcohol (or limit)
  • Grow more fruits and vegetables as well as whole grains.
  • Find a daily activity that allows you to move your body (walking, lightweights, swimming, etc.).
  • Fruits and vegetables are high in antioxidants and nutrient-dense, which means they’re packed with vitamins and minerals when compared to their calorie content.

Whole grains, such as wheat, rye, oats, rice, bulgur, and barley, are unprocessed foods that are high in complex carbohydrates and fiber as well as nutrients.

Spinach, swiss chard, beat greens, lettuce, and romaine are examples of green leafy vegetables.

Broccoli, turnips, brussel sprouts, cauliflower, bok choy, kale, mustard greens are all cruciferous vegetables.

The umbelliferous vegetables include celery, parsley, fennel, and carrots.

Nightshades include eggplant and tomatoes, which are solanaceous vegetables.

Cucurbitaceae vegetables are a kind of squash, pumpkin, cucumbers, and watermelon in the gourd family.

It’s difficult to understand how your body responds to cancer therapy. You’ve been through a lot! What worked for you before may not work now. We are susceptible to change as individuals and as a species.

If you’re having trouble gaining weight as a result of treatment for breast cancer or hormone therapy, talk to your oncologist about it. For a nutritionist’s contact information, see if there is one nearby. Get clarification on what an ideal exercise plan entails for you!

I understand that it is easier said than done, and I’m right there with you! Cancer has a significant impact on our lives, but it also loves ourselves and our bodies; nourish it with care, movement, and nutritious food to get it back in your favor.


Why do you put on weight with Letrozole?

The reduced estrogen levels in the body caused by Letrozole can lead to weight gain.

Does letrozole increase appetite?

There is no evidence to suggest that Letrozole increases appetite.

Do you gain weight with aromatase inhibitors?

Aromatase inhibitors, such as letrozole and anastrozole, can inhibit the conversion of androgens to estrogen. As a result, it does not cause weight gain because you have less estrogen in your body.

Does Letrozole make you retain water?

Letrozole does not cause water retention. It does, however, increase the levels of triglycerides and cholesterol in your body.

How can I avoid weight gain during hormone therapy?

There are several things you can do to maintain a healthy weight while undergoing hormone therapy, including eating a low-sugar diet, avoiding alcohol, and finding a daily activity that allows you to move your body.


Chemotherapy and hormonal therapies can cause a variety of side effects, some of which are beyond our control. However, there are things we can do to maintain a healthy weight during treatment. This includes eating nutrient-dense foods, reducing added sugar consumption, avoiding alcohol, and finding an activity that allows us to move our bodies. By following these tips, you can help your body stay strong while fighting cancer.


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