Ryze mushroom coffee is generally well tolerated, but it can cause digestive issues, dry mouth, dizziness, and other side effects depending on your sensitivity and health status. Because the product combines caffeine, MCT oil powder, and a blend of six mushroom extracts (reishi, lion’s mane, cordyceps, shiitake, turkey tail, and king trumpet), the potential side effects come from multiple ingredients working together.
Digestive Issues Are the Most Common
The most frequently reported side effects are gastrointestinal: bloating, nausea, diarrhea, and stomach cramps. Two ingredients are primarily responsible. MCT oil powder, included for its energy-boosting properties, can cause stomach upset, diarrhea, and vomiting, especially at higher doses or when your body isn’t used to it. Reishi mushroom extract can also contribute to diarrhea, with one clinical trial finding that about 8.6% of participants experienced it.
If you’re new to Ryze, starting with half a serving and building up over a few days gives your digestive system time to adjust. Drinking it with food rather than on an empty stomach also helps, since MCT oil is easier to tolerate alongside a meal.
Dry Mouth, Dizziness, and Insomnia
Reishi mushroom is linked to several mild but noticeable side effects beyond digestion. A cross-sectional survey of over 1,300 people taking reishi found that about 5% reported dry mouth, 3% experienced insomnia, and 3% reported vertigo. A separate clinical trial found higher rates: 16% dizziness and 12% dry mouth. Constipation and itching each appeared in roughly 3% of users in the larger survey.
The insomnia finding might seem counterintuitive since Ryze contains only about 48 mg of caffeine per cup, roughly half what’s in a standard cup of brewed coffee (96 mg). But for people who are caffeine-sensitive or who drink it later in the day, even that moderate amount combined with reishi’s stimulating effect on some individuals can disrupt sleep.
Allergic Reactions
Mushroom allergies are uncommon but real. In one study testing over 1,200 people for sensitivity to mushroom extracts, about 4% reacted to at least one type. Allergic responses to mushroom proteins typically show up as respiratory symptoms (nasal congestion, decreased airflow, sneezing) or skin reactions like itching and hives. In the study, sensitized individuals experienced a mean 73% decrease in nasal airflow when exposed to mushroom allergens.
If you have known mold or mushroom allergies, the concentrated extracts in Ryze pose a higher risk than eating a few mushrooms in a stir-fry. Watch for itchy skin, swelling, difficulty breathing, or a runny nose after your first few cups.
Effects on Blood Clotting
Several mushrooms in Ryze’s blend have anti-platelet activity, meaning they can reduce your blood’s ability to clump together and form clots. Lab research shows that both reishi and lion’s mane inhibit platelet aggregation through different mechanisms. Reishi showed a particularly strong dual anti-platelet effect in laboratory testing.
In the same research, mushroom extracts did not significantly alter standard clotting times in human plasma, which suggests the effect may be subtle at normal dietary doses. Still, if you take blood-thinning medications or have a bleeding disorder, this interaction is worth discussing with your doctor before adding mushroom coffee to your routine. The combination of a blood thinner and a daily dose of anti-platelet mushroom compounds could increase bruising or bleeding risk.
Concerns for People With Autoimmune Conditions
Medicinal mushrooms are widely promoted for “boosting” immunity, but that’s an oversimplification. These compounds are immunomodulators: they can ramp immune activity up or down depending on the dose, the specific extract, and your body’s existing immune state. In animal research, one mushroom extract (maitake D-fraction) actually worsened collagen-induced arthritis rather than suppressing it.
For people with autoimmune conditions like lupus, rheumatoid arthritis, or multiple sclerosis, stimulating an already overactive immune system is the opposite of helpful. The research is not advanced enough to predict exactly how a multi-mushroom blend will behave in someone with autoimmunity, which makes caution reasonable.
Kidney Risk From Chaga-Adjacent Mushrooms
Ryze does not contain chaga, but this context matters because chaga is common in other mushroom coffee brands and is sometimes confused with Ryze’s blend. Chaga mushroom is high in oxalates, and excessive intake has caused acute kidney injury. In one documented case, a 69-year-old man who consumed 10 to 15 grams of chaga powder daily for three months developed calcium oxalate crystal deposits in his kidney tubules, leading to kidney failure with symptoms including swelling, reduced urine output, and confusion.
The mushrooms in Ryze’s formula (reishi, lion’s mane, cordyceps, shiitake, turkey tail, king trumpet) are not known to carry the same oxalate risk as chaga. But if you’re combining Ryze with other mushroom supplements or have a history of kidney stones, keeping track of your total mushroom extract intake is smart.
Pregnancy and Breastfeeding
Clinical safety data on medicinal mushroom supplements during pregnancy and breastfeeding is extremely limited. The North American Mycological Association notes that customary caution means these products are “generally considered unsafe unless they are also a known, safe culinary mushroom.” Lion’s mane, shiitake, and king trumpet fall into the culinary category, but reishi and cordyceps are used almost exclusively as supplements, and their safety profiles during pregnancy are essentially unknown.
The first trimester carries the most concern, since fetal development is most vulnerable to unknown exposures during that window. In the second and third trimesters, risk is generally considered lower, but the decision remains personal and depends on your comfort with limited safety information.
Who Should Be Most Cautious
Most healthy adults can drink a cup of Ryze without significant problems. The people who face the most meaningful risk are those taking blood thinners or anti-platelet medications, those with autoimmune conditions, anyone with a known mushroom or mold allergy, and pregnant or breastfeeding individuals. If you fall into one of those categories, the mushroom extracts in Ryze are the concern, not the caffeine. The caffeine content is modest enough that it’s unlikely to cause issues for anyone who tolerates regular coffee or tea.
For everyone else, the most likely side effects are mild digestive discomfort and dry mouth, both of which tend to improve as your body adjusts over the first week or two of use.