Serm Vs. AI: Which One Is Better For You?

Is your estrogen level increasing day by day? After going to different doctors, some of them might suggest SERMs and some AIs. It is okay to get confused in this situation.

So, which is the best option for you SERM vs. AI?

SERMs blocks only the estrogen from breast tissues from attaching itself to the receptors. On the other hand, AIs stop the enzyme aromatase to function. Which leads to a complete stoppage of estrogen production. Its side effects are much more fatal and long-lasting than SERMs. 

But, there is more to the story than it meets the eye. You have to read the full article to clear all your confusion to make the decision.

So, let’s get down to it.

SERM Vs AI: Quick Comparison

We need to know a little bit about them before we can compare them. It will help us know what they are and how they work. Then we will be able to easily distinguish them. 

SERMs stand for selective estrogen receptor modulators. It is a type of medication that both blocks and mimics estrogen’s effect on the body. The most common types of SERMs are raloxifene, Nolvadex, clomiphene, and toremifene. 

AI stands for aromatase inhibitors. It is a type of medication that stops an enzyme called aromatase in fat tissue. It lowers the estrogen level by stopping other hormones to change into estrogen. The most common AIs are exemestane, letrozole and anastrozole.

FunctionIt blocks only the estrogen from breast tissues from attaching itself to the receptors. It stops the enzyme aromatase to function. Which leads to a complete stoppage of estrogen production.
Cycle5-10 years5 years
Effectiveness and BenefitsEffective for breast cancer, osteoporosis, and increasing ovulationEffective for cancer, gynecomastia, and ovulation induction.
Side EffectsSimilar side effects as menopause. They include- hot flashes, nausea, vaginal dryness, thin bone, etc.More severe side effects like heart attack, high cholesterol, decreased bone density, liver inflammation, etc. 

We have to know them in a little bit more detail to choose the better one.

SERM Vs AI: Detailed Comparison

Hope the table prepared you for the face-to-face comparisons. We will help you to choose and show you the better one. So, let’s get straight to the facts.


As we know, when the receptor gets attached to estrogen, it sends a signal. That tells the tumor cell to grow. What SERM does is that it blocks the estrogen from attaching to the receptors. That is why the cells cannot multiply. 

It stops the cancer growth in the breast. Many types of cells have estrogen receptors including the uterus and bone cells. But SERM only stops the specific breast estrogen receptors. That is why it is called ‘selective’. 

The other way to do this is by AI. There is an enzyme called aromatase in the body. That converts hormones such as androgens by a process called aromatization to estrogens. It helps stimulate the tissues in the breast to grow. Even works for cancer cells.

Decreasing the production of estrogen would help limit and control the growth of cancer. AI exactly does this by stopping this at its root. As it stops the function of the aromatase enzyme to produce estrogen. It lowers the level of estrogen in the body as a whole. 

Therefore, we can see that both of them work in different ways. But their main goal is the same. Which is to lower the overall estrogen level in your body to help control cancer.

Winner: AIs completely stop the production of estrogen. Therefore, we can they are the clear winner here. 



Every medicine has a cycle that needs to be followed to complete the dosage. Only by completing it, the main objective of it can be achieved. 

For SERMs, doctors generally prescribe a long-term treatment of 5 to 10 years. Because it only targets a specific tissue, it takes a little bit more time.

On contrary, for AIs, the treatment time is up to 5 years prescribed by doctors. Because it is a much more impactful process. As it stops estrogen production from its roots.

Winner: AIs are better in this category.

Effectiveness and Benefits

Not all medications are as effective and are applicable for everything. We have to know them before we can compare which is more effective than the other.


There are a couple of different SERMs. Each of them has different uses and functions. You should listen to what your doctor prescribes. 

For Breast Cancer

Breast cancer that is ER-positive is mostly treated by a SERM named tamoxifen. This type of cancer cell also has an estrogen receptor that grows in touch with it. 

What tamoxifen does is that it stops the receptor from binding it with estrogen. It leads to stopping the growth. 

Taking raloxifene and tamoxifen can hugely reduce the chance of breast cancer. USPSTF recommended it for women. As there is a high chance of women having breast cancer. And these SERMs are capable of reducing it with very few side effects.

For Osteoporosis

For osteoporosis patients, raloxifene is the most used SERM. As it mimics the beneficial effects of estrogen to treat osteoporosis patients. According to studies, it increases 2-3% of the bone density near the hips and lower spine. 

Raloxifene decreases about 50% of vertical fractures in the body. Also, decreases other major fractures by about 22%. 

For Other Conditions

A SERM named Clomid helps women with infertility. As increases ovulation for premenopausal women. It creates an effect on the pituitary gland just like estrogen. Which leads to an increase in gonadotrophin activity. It helps both in menstruation and ovulation.

Bazedoxifene is a type of SERM that decreases the symptoms of uncomfortable menopause. These symptoms are hot flashes and vaginal dryness.


As with SERMs, AI also has some different types. Each of them serves different functions than the other.

For Cancer

For postmenopausal women, estrogen is produced in the tissues that are in the periphery areas. Aromatase enzyme converts other hormones to estrogen to fulfill the needs. But this hormone increases the spread of the cancer cells.

AIs stop the function of the enzyme to lower its production of estrogen. Which is an effective way to control cancer. 

According to research, women taking AIs had a better result than those taking SERMs.Also, the survival rate and side effects were comparatively better for AIs.

For Gynecomastia

AI such as testolactone is used for gynecomastia treatment in adolescents and children.

For Ovulation Induction

AI such as letrozole is used to help with female infertility. It helps the ovulation induction process to stimulate better.

Letrozole lowers the frequency of live birth and multiple gestations compared to SERMs. 

Winner: Both of them have similar effectiveness, which is why it’s a draw in this category. 

Side Effects

Everything comes at a cost, especially the ones that are man-made medications. Before using, we should check the side effects first to see if they are rational to use. 


Each of the SERMs has its side effects, which we have to keep in mind. Some of them are similar to menopause. And some are even long-lasting for our bodies. These include-

  • Vaginal dryness or bleeding
  • Increased chance of cancer in the uterine
  • Clouding of the eye
  • Thin bones
  • Blood clots in the lungs or the legs
  • Nausea
  • Hot flashes

Tamoxifen also makes the tumor flare after use. Which creates pain in the bone and grows the tumor. But slowly these go away. 

Therefore, if your doctor recommends SERMs to you. It is better to follow his prescription strictly to avoid these side effects. 


Research found that the chance of having a heart attack is higher in AIs than SERMs. Even if AIs have more benefits, we have to include the risk also in the equation. 

There are a few more serious side effects that also need to be incorporated. It would help us to make a more rational decision while choosing. They are-

  • High cholesterol
  • Heart failure
  • Decrease in bone density and structure
  • Angina
  • Liver inflammation
  • Decreased interest in sex-related activities
  • Hot flashes
  • Depression
  • Joint pain
  • Thinning hair

Therefore, we can see the side effects of AIs are much more severe than SERMs. Some of them are enough to kill you. 

For gymnasiums, taking steroids but not working out may also increase estrogen levels. It might lead to these types of side effects or some severe consequences.

Winner: SERMs are a clear winner in this category for having less severe side effects.

Final Verdict 

After the face-to-face comparison, the result might seem clear to you. As in some aspects, SERMs were better and in some others, AIs were better. 

For many people who are concerned about consequences, SERMs may be the better option to choose. Because they have much less severe side effects. And both of them are doing similar things.

After taking medications like these, it is very common to have forearm pain for bodybuilders. 

There are also a few medications that you can use. They are mostly recommended by doctors for fighting against those side effects. They are-

Urgent Liver 911It contains over 23 ingredients that help support the liver
Heart HealthIt not only supports your health but also protects it from damages caused by inflammation. 
Lectin ShieldIt helps to reduce the pains in your joint


Is It Safe To Take Both Serm And Ai?

According to a study conducted on about 1200 people. Who were all given both SERM (Nolvadex) and AI (Arimidex) at the same time. The side effects that occurred were less than 1%. Therefore, we can say it is safe to take both.

What Is The Best Naturally Available Ai?

Grape seed extracts can be very easily found in nature. The research found that they work exactly like any other AI. As it also stops the aromatase from functioning and lowers the estrogen level. 

What Is The Best Natural SERM?

Phytoestrogens are similar to SERMs like tamoxifen. They can be very easily found in human foods. Such as apples, pears, beans, grains, onion, garlic, tea, wine, etc. It helps lower the estrogen level significantly. 


I hope you’re no longer confused about SERM vs AI.

Both of them do a similar thing, which is to lower the estrogen. But while doing so, AI leads to some serious side effects. This is why I prefer SERM over AI. Nonetheless, both of them have really good benefits to offer.

Have a nice and healthy life!

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