Cordyceps Dangers: Are Cordyceps Mushrooms Safe?

If you were an avid watcher of The Last of Us in 2023, you probably got a little concerned when you recognized one of those words in your functional mushroom powder: cordyceps. 

Yep, those same brain-infecting, zombie-inducing mushrooms that have been used in traditional Chinese medicine practices for thousands of years. 

Well, they’re not quite the same—while both are in the Cordyceps family, the species we consume is Cordyceps militaris or Cordyceps sinensis. Rather, Pedro Pascal was more worried about a mutant strain of Ophiocordyceps unilateralis.

Television shows aside; you may wonder if the so-called safe cordyceps actually are safe or if there are any potential side effects or dangers to look out for. In this article, we’ll detail everything you need to know about cordyceps mushroom safety and the leading health benefits.

What Is Cordyceps?

Cordyceps is a mushroom with over 600 species—and, yes, they are all parasitic, but some are also considered medicinal mushrooms. 

Although consuming a parasitic fungi doesn’t sound like it would be good for human health, there are a couple of species that have been shown to provide health benefits: Cordyceps militaris and Cordyceps sinensis (also known as Ophiocordyceps sinensis). 

Most Cordyceps species infect ants and other insects, including Cordyceps sinensis, also known as the “caterpillar fungus.” It parasitizes the larvae of ghost moths and grows from the head of a dead caterpillar—but only at high elevations in Tibetan plateaus of the Himalayan mountains and some Chinese provinces.¹

However, Cordyceps sinesis is very rare in the wild due to the specific environmental growing conditions necessary for it to thrive, including the fact that the fruiting body needs to grow out of the caterpillars’ heads. This makes it difficult to cultivate commercially and raises concerns about animal ethics.¹ 

Combined with the knowledge that it’s now overharvested in the wild, Cordyceps sinesis is rarely used in supplements or clinical trials and is incredibly expensive. Some reports state it can sell for up to $40,000 per pound! Instead, we can use Cordyceps militaris, which has a similar health profile and can be grown commercially (no dead Tibetan caterpillars required).² 

Both of these edible Cordyceps species have similar health benefits, but C. militaris has more of the compound cordycepin—a bioactive component that helps with inflammation, cell growth regulation, and immunity. Cordyceps also contains adenosine, a compound beneficial for energy and the cardiovascular system that supports our production of ATP. Both species provide polysaccharides called beta-glucan, which help modulate or balance proper immune cell function.³

But are there any dangers to consuming cordyceps? Let’s find out.

Potential Cordyceps Supplements Side Effects

Again, we’re not talking about the potentially mutant sci-fi cordyceps here; this is strictly based on the edible forms of the fungi (Cordyceps militaris and Cordyceps sinensis). 

Cordyceps has been used for thousands of years. Although clinical trials weren’t around way back then, no significant adverse effects have been reported in recent years. 

Some minor side effects may arise, especially in higher doses, including:

• Nausea
• Diarrhea
• Constipation
• Stomach discomfort
• Dry mouth 

However, although it’s been used for many years in traditional practices, long-term safety research hasn’t been performed, so we don’t know for sure if any side effects will arise when taking it long-term.

People who are pregnant or breastfeeding should not use cordyceps due to insufficient evidence showing that it’s safe in these conditions. 

Certain medications, including diabetes drugs, may interact with cordyceps. As cordyceps may lower blood sugar levels, taking it with a blood sugar-lowering drug may cause hypoglycemia. If you’re unsure if you should be taking cordyceps in supplement form, speak with your healthcare provider first.

Cordyceps may also interact with blood thinner medications, lowering their efficacy or increasing the risk of bleeding. 

Overall, the potential side effects of Cordyceps mushrooms are pretty mild—no zombie-induced brain takeovers here. 

Potential Health Benefits of Cordyceps

So, what does cordyceps do for the body? The primary cordyceps benefits include: 

• ​​Increased exercise performance and energy: The stamina-boosting effects of cordyceps fungi have been recognized by sherpas in the Himalayan mountains for centuries. At those high altitudes, they noticed they could breathe easier, expend more energy, and have more endurance on long treks after eating cordyceps. In clinical research, cordyceps has shown promise for improving exercise performance, which is likely due to increased ATP production.⁴ Another study found that 3 weeks of taking a cordyceps supplement (3g/day) reduced time to exhaustion and increased VO2max after high-intensity exercise.⁵  
• Immune system support: Cordyceps has been found to modulate the activity of several immune cells, which means some can get stimulated while others are suppressed. For example, cordyceps has been found to increase the activity of natural killer cells, which can improve cellular immune response.⁶ 
• Reduced inflammation: Cordyceps also modulates the activity of cytokine signaling molecules, suggesting the potential for helping with chronic inflammation.³ 
• Improved cardiovascular health: Research shows that cordyceps had a positive effect on people with heart arrhythmias when combined with standard medications.⁷ Cordyceps may benefit heart health due to its antioxidant and anti-inflammatory properties and ability to increase ATP production and VO2max.⁵ 
• Reduced blood sugar: In animal research studies, cordyceps can decrease blood sugar levels comparably to the diabetes drug metformin. However, human research is needed.⁸
• Improved kidney function. In a meta-analysis of 22 studies, cordyceps produced significant improvements in kidney health in people with chronic renal insufficiency or renal failure. This included improved blood biomarkers associated with chronic kidney disease, like reduced serum creatinine and proteinuria (protein in the urine) and increased albumin levels.⁹

Cordyceps FAQs