Kratom's effects on the mind are well-established. In low-to-moderate quantities, kratom has sedative, stimulative, euphoric, and pain-relieving properties. But less is known about how the plant affects one of the body's most vital organs, the heart.
Anecdotal evidence and some scientific research suggest that kratom may temporarily alter heart function. But does this mean that those with heart problems should avoid kratom? And what kind of heart-related side effects can arise from chronic kratom use, if any?
Let's take a look!
Tachycardia — the medical term for an elevated heart rate above 100 BPM — is a temporary side effect of many widely-consumed and legal drugs, such as caffeine and nicotine. Some researchers have also identified tachycardia as a temporary side effect of kratom use (Anwar et al., 2016).
It's important to note that tachycardia doesn't always pose a health risk. In many cases, it subsides on its own without causing adverse effects. However, in some people, tachycardia can disrupt normal heart function and lead to serious complications such as heart attack or stroke.
In one study, researchers found that mitragynine — one of kratom's primary alkaloids — temporarily increased blood pressure and heart rate in chronic kratom users eight hours after ingestion (Trakulsrichai et al., 2015). Another study (Kruegel et al., 2018) noted that kratom-induced tachycardia occurs more often with higher kratom consumption (8 grams or more), a dosage that most kratom users would consider higher-than-normal.
There is some evidence that tachycardia may not be a common side effect for all kratom users. In a review of twelve cases reported to poison control centres, less than half of kratom consumers (42%) experienced tachycardia (Cumpston et al., 2018). However, more clinical research is needed to determine whether tachycardia is a common side effect of kratom.
Kratom has been implicated in numerous adverse events and even fatal poisonings over the years. However, in the majority of these cases, it was used in combination with other drugs such as O-desmethyltramadol (Kronstrand et al., 2011). These events, in addition to reports of tachycardia, have led researchers to ponder whether kratom is cardiotoxic, or can damage heart muscle. Cardiotoxicity occurs when the heart muscle or electrophysiology is damaged, and the heart cannot pump as effectively.
In one such study (Lu et al., 2014), a team of scientists administered mitragynine and other naturally-occurring kratom alkaloids to isolated heart cells, called cardiomyocytes. They then measured the electrical signaling of the heart cells to determine if mitragynine had altered their function.
While the researchers didn't find kratom derivatives to be directly toxic to heart cells, they did find that mitragynine may cause some adverse cardiac consequences. At high doses or in people with a genetic predisposition, metabolites of mitragynine may block a potassium channel in the heart leading to dysfunction. This reaction could lead to heart rhythm problems such as abnormal repolarization, QT prolongation, and a potentially fatal condition called Torsades de pointes.
However, the authors did conduct the experiment with mitragynine levels "at concentrations close to the plasma levels reported in lethal cases," which may not translate to many real-world users. More research would be needed to determine if these mitragynine metabolites induce changes in cardiac functioning at lower-to-moderate doses (1-5g). However, chronic kratom users who use the plant in excess and people with a genetic predisposition to heart problems could be at risk of developing adverse cardiac events.
Today, scientists know that heavy metal intake can increase your risk of cardiotoxicity or heart muscle damage. Heavy metals — such as lead, cadmium, and mercury — are found naturally in foods and our environment. However, elevated exposure and consumption of these metals are toxic to humans.
Unfortunately for kratom users, low-quality, untested kratom products can contain elevated levels of heavy metals like lead. These contaminated kratom products are often grown and processed in compromised environments and processed using lead-lined equipment. As a result, the kratom users who consume these contaminated products can be unknowingly exposed to lead levels that are significantly higher than the naturally-occurring levels found in kratom leaves. Over time, the use of these contaminated kratom products could increase their risk of cardiotoxicity.
Thankfully, you can reduce your risk of developing kratom-related heart issues by purchasing kratom products from trusted vendors. When shopping for kratom, look for vendors that third-party test their products for heavy metals and publish their lab results online. Although no kratom product is 100% safe, lab-tested kratom products are less likely to endanger your health than products that may be cheaper but are untested and possibly unfit for consumption.
Moderation also appears to be key. As the aforementioned studies show, the risks of tachycardia and cardiotoxicity may be higher for chronic, heavy kratom users. More research is needed to determine best dosing.
Kratom is a drug, and like caffeine or nicotine, it can temporarily affect the way your heart operates. A smaller number of studies have also shown that kratom could increase the risk of developing some adverse cardiac side effects. That said, these risks may be more associated with heavy kratom use or people genetically predisposed to heart problems.
If you're a kratom consumer, ensure that you're using lab-tested, uncontaminated kratom products in moderation. Also, use caution or avoid combining kratom with any other drug or supplement. While not foolproof, these factors could minimize the heart-related risks of kratom and allow you to continue using the plant while keeping your heart happy and healthy.