Is Daily Aspirin Therapy a Wise Choice?

aspirin therapy risks

Story at-a-glance

  • Low-dose aspirin therapy has long been recommended to lower your risk of heart attack, and an estimated 36 percent of American adults are currently on it. However, a number of studies have refuted its benefits
  • Mounting evidence suggests that daily aspirin has no benefit for otherwise healthy people who are at low risk for heart attack
  • High iron is a significant risk factor for heart disease and aspirin therapy lowers your iron level through intestinal bleeding
  • Checking your ferritin and lowering your iron by donating blood if it’s high is a safer strategy


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Low-dose aspirin therapy has long been recommended to lower your risk of heart attack, and an estimated 36 percent of American adults are currently on it.1 Think about it: That's more than 1 in 3 persons in the U.S.

The conventional justification for this recommendation is that aspirin slightly decreases your blood's ability to form dangerous clots due to prostaglandin inhibition.

However, a number of studies have refuted its benefits, and there's no shortage of controversy surrounding this subject. In 2014, the U.S. Food and Drug Administration even reversed its stance on daily aspirin therapy, noting:2,3

"FDA has concluded that the data do not support the use of aspirin as a preventive medication by people who have not had a heart attack, stroke or cardiovascular problems, a use that is called 'primary prevention.'

In such people, the benefit has not been established but risks — such as dangerous bleeding into the brain or stomach — are still present."

1 in 10 People May Be Inappropriately Using Aspirin Therapy

According to a 2015 study4 published in the Journal of the American College of Cardiology (JACC), more than 10 percent of patients are inappropriately using aspirin therapy for primary prevention of cardiovascular disease (CVD), as they have a 10-year CVD risk that is lower than 6 percent (low risk).

Overall, mounting evidence suggests that daily aspirin has no benefit for otherwise healthy people who are at low risk for heart attack. The benefits may still outweigh the risks for some people, however I believe there is a far safer way to achieve the benefit of aspirin therapy without ever touching an aspirin.

While the conventional view is that aspirin reduces your heart attack risk by thinning your blood, that may not be the primary mechanism imparting the benefits we see. It may actually be related more to its effect on your iron levels, which I'll explain below.

Aspirin Controversy Lives On

In 2002, Dr. John G. F. Cleland, a cardiologist from the University of Hull in the U.K., wrote an excellent article published in the British Journal of Medicine (BJM),5 casting serious doubt on the efficacy of aspirin therapy for the prevention of heart attacks.

Based on a series of meta-analyses from the Antithrombotic Trialists' Collaboration6 (an enormous body of research following more than 100,000 patients at high risk for cardiac events), Cleland concluded that aspirin therapy was not saving lives.

The number of non-fatal events was reduced, but the number of sudden deaths actually increased. What Cleland discovered was that aspirin can actually mask a cardiac event in progress. In other words, aspirin may change the way vascular events present themselves.

Cleland also found that studies touting aspirin's benefits were seriously flawed and riddled with bias.7 Since then, many other studies have further refuted the use of aspirin as a form of heart attack prevention, especially if you do not have a history of heart problems.

Aspirin May Lower OR Raise Risk of Heart Attack, Depending on Your Situation

Following the FDA's turnabout on daily aspirin, Cleland wrote:8

"The cause of most heart attacks is rupture of cholesterol deposits (plaque) in the wall of the blood vessels supplying the heart muscle. Rupture of the plaque exposes the cholesterol 'soup' to the blood inside the artery, causing a blood clot.

Aspirin reduces the stickiness of the blood, which can prevent some blood clots forming and cause others to break up without doing too much harm. However, plaque rupture is also often caused by bleeding from tiny, fragile blood vessels that grow into the plaque from outside the artery wall.

So, while aspirin could prevent some heart attacks, by stopping clots forming, it may trigger others by causing bleeding into the cholesterol plaque, resulting in no overall benefit in terms of heart attack or stroke prevention.

The FDA still suggests that aspirin is beneficial for people who've already had a heart attack or stroke, but I think the evidence for taking it for more than four weeks after such an event is also weak."

To this day, the controversy continues. Most recently, research9 by Dr. David Agus at the University of Southern California Keck School of Medicine suggests aspirin may in fact lower the risk of heart attack in those over 50 who are at high risk, and may reduce their risk of cancer as well.

Advice on Aspirin Treatment Varies

While the FDA no longer recommends daily aspirin for those without a history of heart problems, the American Heart Association (AHA) and the U.S. Preventive Services Task Force (USPSTF) still do, as long as you're considered high risk. As reported by Time magazine:10

"They call for calculating an individual's specific risk of developing heart disease in the next 10 years, based on a number of factors including their age, family history of heart trouble, blood pressure and cholesterol levels.

Despite that advice, however, 40 percent of men and 10 percent of women who fit those criteria and should be taking aspirin are not, according to the latest study.11

The authors also predict that if everyone who meets the conditions would take the drug as recommended, an estimated 900,000 more people would be alive by 2036. That's because for every 1,000 people, 11 cases of heart disease and four cases of cancer would be averted …

The findings should push more people toward the AHA and USPSTF advice, which calls for people to discuss with their doctor their individual risk and benefit ratio …"

Weigh Risks and Benefits of Daily Aspirin Therapy

As you can see, there's a boatload of controversy on the benefits of low-dose aspirin. It's important to understand and weigh the risks and benefits based on your individual situation.12,13

Whatever you decide, you also need to understand that abruptly stopping daily aspirin therapy can have a rebound effect that can trigger a life-threatening heart attack.

Before you start daily aspirin therapy it would be wise to consult with a health professional about your specific circumstances.

However, they may not be aware of the dangers of elevated iron levels and their association to heart disease and cancer. So, make certain they appreciate these issues before giving you any recommendation.

Why Most of Us Have Iron Levels That Are Too High

Unfortunately, our focus for the last 70 years has been on the deficiency end of the equation. If you have too little iron, you may experience fatigue, decreased immunity or iron-deficiency anemia, which can be serious if left untreated.

Anemia affects more than a third of the global population, and is most common in children and premenopausal women.14 However, only a relatively small fraction of these anemias is due to iron deficiency. (A precise estimate is difficult to obtain because the proper testing and protocols have not been in place.)

Most people, physicians included, fail to appreciate that — aside from blood loss, including menstruation — the body has no significant way to excrete excess iron. There are very minor amounts lost through normal bodily processes, but not enough to move the needle on overall iron levels.

Between supplementation, fortification and the iron that occurs naturally in foods such as meat, shellfish and beans, the iron load can quickly add up to excessive levels. For adult men and postmenopausal women, these levels can, and as you will see, frequently rise to levels that promote disease inception and severity.

Why Is Excess Iron a Problem?

When your iron levels are in excess, which is typically a ferritin level above 60 nanograms per milliliter (ng/ml), then iron actually is a potent oxidant that catalyzes the formation of excessive free radicals that damage your cellular and mitochondrial membranes, proteins and DNA.

Excess iron is a potent contributor to increased risks of cancers, heart disease and neurodegenerative diseases. This is likely why those that donate blood regularly (two to three times per year) have a much lower risk of these diseases.

Menstruating women typically lose iron every month through their menses and, like children, are at risk for iron deficiency; it is uncommon for them to have high iron/ferritin levels. But most adult males and postmenopausal women likely have excess iron and need regular blood testing for ferritin.

Why Phlebotomy May Be a Better Option Than Aspirin Therapy

Getting back to aspirin, the blood loss may in fact be part of how aspirin works to lower your risk for heart attack in the first place. By causing chronic blood loss, it lowers your iron level. Unfortunately, few physicians fully appreciate the danger of excess iron. Hence the problem tends to go undetected. If left untreated, high iron can damage your organs and contribute to cancer, heart disease, diabetes, neurodegenerative diseases and many other disorders.

While iron overload is dangerous, it is easy and inexpensive to treat. All you really need to do is monitor your serum ferritin and/or gamma-glutamyl transpeptidase (GGT) levels, avoid iron supplements and be sure to donate blood on a regular basis. By doing this, you can avoid serious health problems.

Aspirin Use May Lower Your Iron and Ferritin

As shown in a 2001 study,people taking seven aspirins per week had 25 percent lower mean serum ferritin than nonusers. The effect was most15 marked in diseased subjects, compared to healthy ones. As noted by the authors:

"Atherosclerosis, a primary cause of myocardial infarction (MI), is an inflammatory disease. Aspirin use lowers risk of MI, probably through antithrombotic and antiinflammatory effects. Because serum ferritin (SF) can be elevated spuriously by inflammation, reported associations between elevated SF, used as an indicator of iron stores, and heart disease could be confounded by occult inflammation and aspirin use if they affect SF independently of iron status …

Aspirin use is associated with lower SF. We suggest this effect results from possible increased occult blood loss and a cytokine-mediated effect on SF in subjects with inflammation, infection or liver disease. The relations between aspirin, inflammation and SF may confound epidemiologic associations between elevated SF, as an indicator of iron stores, and heart disease risk."

But please understand that donating blood is a far safer way to lower your iron level than taking aspirin and losing blood via internal bleeding. Unfortunately, most will not do it. Hence, aspirin therapy might make sense for some, as elevated iron is a massive risk factor that conventional medicine does not yet fully recognize and address.

How High Is Too High?

The serum ferritin test measures your stored iron. I strongly recommend getting a serum ferritin test done on an annual basis. It's fairly inexpensive, typically less than $40. Your doctor can write you a prescription for it, or you can order it from

They recently also added a GGT test. This test measures liver enzymes and can tell you if you have liver damage, but the GGT can also be used as a screening marker for excess iron. The free iron measured by GGT is a great indicator of sudden cardiac death.

Just don't make the mistake of going by what's considered "normal."16 In some labs, a ferritin level of 395 ng/ml falls within the normal range, which is FAR too high for optimal health. In reality, you're virtually guaranteed to develop disease at that level. For optimal health, the ranges you'll want are:

  • Serum ferritin: ideally between 20 and 80 ng/ml. Certainly no higher. As a general rule, somewhere between 40 and 60 ng/ml is the sweet spot for adult men and non-menstruating women.
  • GGT: For women, a healthy GGT level is around 9 U/L, whereas the high end of "normal" GGT lab ranges are generally 40 to 45 U/L for women. For men, a level of 16 U/L is recommended (normal lab ranges for men is 65 to 70 U/L).17

Again, if your iron level is high, the solution is to simply donate your blood. If you're an adult male, you'll want to donate blood two to three times a year once your levels are normal. If ferritin levels are over 200 ng/ml, a more aggressive phlebotomy schedule is recommended. Although your local blood bank may not realize this, recent U.S. legislation allows all blood banks to perform therapeutic phlebotomy for hemochromatosis or iron overload. All you need is a doctor's order.

Are You a Candidate for Daily Aspirin?

Getting back to aspirin therapy, provided you do not have a bleeding or clotting disorder that makes you bleed easily, or currently suffer from bleeding ulcers, many conventional doctors will recommend daily aspirin therapy if:18,19

You have had a heart attack or stroke.

You have not had a heart attack, but have a coronary artery stent, have had bypass surgery or suffer chest pain due to coronary artery disease.

You have not had a heart attack, but are at high risk for one (although the FDA does not support this recommendation).

You have diabetes and are a man over 50 or woman over 60, and have at least one additional risk factor for heart disease, such as smoking or hypertension (high blood pressure).

However, it's worth noting that a number of studies20,21 have not found any clear benefit of aspirin therapy for diabetics. For example, a Swedish study22 published in 2009 found no evidence suggesting that aspirin helps lower the risk of heart attack in diabetics.

Meanwhile, they did find it can increase the risk for serious bleeding in some patients. According to these researchers, guidelines for aspirin therapy in diabetic patients should be revised until further studies can prove its safety and effectiveness.

Beware of Dangerous Drug Interactions

Overall, most organizations now agree that the benefits of daily aspirin do NOT outweigh the risks of bleeding if you have a low risk of heart attack. As a general rule, the greater your risk of heart attack, the more likely it is that the benefits of daily aspirin may outweigh the risks.

Be mindful of the fact that most of these studies never evaluated the lowering of ferritin levels to tease out the benefit. I suspect if they had, you would see a far more powerful impact. On the downside, even though the risk is relatively mild with low-dose aspirin therapy, your risk of internal bleeding increases with advancing age.23

Also, taking other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, while on aspirin therapy can increase your risk for internal bleeding by as much as 300 to 400 percent.

Taking daily aspirin while on Plavix, an anti-platelet drug that works by thinning your blood and making it less likely to clot, can have particularly deadly consequences. Plavix is promoted for the prevention of strokes and heart attacks. However, research has shown that when combined with aspirin, the drug nearly doubled the death rate from heart disease among patients who had not had a previous heart attack but were at risk, compared to those taking aspirin alone.

Another study24 investigating the effects of Plavix in combination with aspirin versus using aspirin alone for the prevention of stroke and cognitive decline later confirmed these disturbing results.

In fact, the anti-platelet arm of the study was terminated25 and patients were told to stop taking Plavix and take aspirin only, as it became apparent the Plavix-aspirin regimen significantly increased the risk of death. The combination also doubled the risk of gastrointestinal bleeding, and more than doubled fatal hemorrhaging.

Aspirin Therapy Affects Sexes Differently

Complicating matters further, studies have discovered aspirin affects men and women differently, imparting different benefits. In one analysis of six trials,26 aspirin therapy lowered the risk of heart attacks in men with a moderate to high risk of heart disease or stroke by 32 percent, but did not affect their risk of stroke.

In women, it had the converse effect. Aspirin lowered the risk of stroke by 17 percent in those with moderate to high risk of heart disease or stroke, but did not affect the women's risk of heart attack. Based on these data, the USPSTF recommends the use of one baby aspirin per day or one regular strength aspirin every other day for the primary prevention of disease as follows:27,28

  • For men between 45 and 79 years of age to reduce risk of heart attack when a net benefit is present, meaning a reduction in myocardial infarctions outweighs the potential harm due to an increase in gastrointestinal hemorrhage
  • For women between 55 and 79 to reduce risk of ischemic stroke when a netbenefit is present (reduction in ischemic strokes outweighs the potential harm of an increase in gastrointestinal hemorrhage)

Typical Dosages and Warning Signs of Internal Bleeding

Typically, people on a daily aspirin regimen will take one "baby aspirin" per day, which contains 75 to 81 milligrams (mg) of aspirin, or one full strength dose of 300 to 325 mg every other day. This is a wide range of doses. If you are considering low-dose aspirin therapy it would seem far more prudent to take one baby aspirin a day rather than one full aspirin that is 400 percent stronger.

Lowering the dose should radically decrease the side effects without diminishing the benefits. If you're on daily aspirin, look for signs of hemorrhaging, which include but are not limited to vomiting blood or dark brown granules resembling coffee grounds, and/or black tarry or bloody stools. If you have any of these, be sure to call your doctor immediately.

Recommendations for a Healthy Heart

There's reason to believe that one of the benefits of aspirin therapy is not a result of thinning your blood but rather the fact that it lowers your iron level through chronic low level internal bleeding. Knowing this, you can monitor your ferritin levels to get it between 40 and 50 ng/ml, and lower your iron by donating blood if your iron level is too high. This would be a far safer strategy.

It's important to remember that your heart health is dependent on your lifestyle choices — not your intake of aspirin. The real key to preventing heart disease is to use a combined approach, one that treats all facets of your physical and emotional health. To optimize your heart health and reduce your chances of a cardiac event, be sure to address the following lifestyle factors:

Eat real food and avoid processed foods, preservatives, additives, artificial sweeteners and grains as much as possible. Make sure your diet contains abundant fresh organic vegetables.

Restrict your consumption of fructose to less than 25 grams per day. High sugar intake, especially fructose, is directly tied to cardiovascular disease.

Incorporate high-quality animal based omega-3 fats into your diet to optimize your omega 6:3 ratio. An excellent animal source of omega-3 is krill oil.

Make sure you are getting adequate vitamin D (ideally from sun exposure) and vitamin K2, since both are necessary for good cardiovascular health.

Be sure you're getting enough exercise.

Optimize your sleep, which is essential for every aspect of your health.

Optimize your body weight and composition.

Keep an eye on your blood pressure, blood glucose and insulin levels, iron level and lipid profile.


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