Can I Take Reishi Mushroom with Wegovy?

Does reishi interact with Wegovy?

Reishi and Wegovy have not been tested together, so no interaction is established.

Semaglutide is a GLP-1 receptor agonist given once weekly under the skin [6]. The Wegovy label describes its breakdown as proteolytic cleavage of the peptide backbone plus beta-oxidation of its fatty acid side chain, rather than metabolism by CYP enzymes, and about 3% of a dose is excreted unchanged in urine [6]. The label's drug interactions section addresses insulin and insulin secretagogues, where hypoglycemia risk rises, and oral medicines, where delayed gastric emptying may change absorption [6].

Reishi capsules are oral supplements. The Wegovy label states that semaglutide delays gastric emptying and may affect absorption of oral medicines, and says to consider increased clinical or laboratory monitoring for oral drugs with a narrow therapeutic index or that require clinical monitoring [6]. No study was identified that tested whether Wegovy changes reishi absorption or whether reishi changes semaglutide exposure.

What reishi is, and what has been tested in people

Reishi (Ganoderma lucidum, also called lingzhi) has been used in Asian medicine for more than 2,000 years and is sold in the US as an over-the-counter dietary supplement — powder, extract or capsule [4][5]. A search of Drugs@FDA for ganoderma returns no approved drug application [4].

The human studies are small and short. Doses that appear in them: 1.5 g a day for 4 weeks in a hemostasis trial of 40 volunteers [3]; 2 g twice daily for 10 days in a 16-person safety trial [7]; 1.4 to 3 g a day for 12 to 16 weeks in the type 2 diabetes trials pooled by a Cochrane review [5]. These are study doses, not recommended doses.

Does reishi raise bleeding risk?

The bleeding warning attached to reishi comes from laboratory work, not from people. The human test went the other way. In a randomized, double-blind, placebo-controlled trial, 40 healthy volunteers took reishi capsules 1.5 g a day (n=20) or placebo (n=20) for 4 weeks, with a routine coagulation screen, fibrinogen, von Willebrand ristocetin cofactor activity, PFA-100 and thromboelastography measured before treatment and at 4 and 8 weeks. There were no significant between-group differences, and every measurement stayed within the normal range. The authors concluded that reishi was unlikely to increase surgical bleeding risk in otherwise healthy patients [3].

The limits of that result matter. The volunteers were healthy, not people taking blood thinners, and 4 weeks is a short exposure. No human interaction study of reishi with an anticoagulant or antiplatelet drug was identified.

What about the liver?

Reishi's liver signal rests on case reports. A 2007 report described fatal fulminant hepatitis after 1 to 2 months of Ganoderma lucidum mushroom powder, and noted a similar case first described in Hong Kong in 2004; both patients were taking other therapeutic agents, and both had previously taken boiled lingzhi without toxicity [1]. A 2023 report described a 47-year-old man who developed acute hepatitis with significant transaminitis after reishi powder and alcohol; he was treated with N-acetylcysteine and intravenous fluids and had complete resolution of symptoms and laboratory abnormalities at a two-week follow-up [2].

Case reports describe events; they cannot show what caused them, and in the 2007 report other medicines were in the picture [1]. On the Wegovy side, the label's warnings cover pancreatitis, gallbladder disease, acute kidney injury from volume depletion and severe gastrointestinal reactions [6].

The 10-day safety trial found no adverse effects on symptoms, ECG, blood counts, blood chemistry or urinalysis in 16 people taking 2 g of reishi extract twice daily, and its authors said a longer, dose-escalating safety trial was warranted [7].

Blood sugar and the hypoglycemia warning

The useful safety question for a Wegovy user is whether reishi adds glucose lowering on top of a drug that already lowers glucose. The pooled trial data do not show that it does. A Cochrane review of 5 trials (398 people; the 3 analyzed trials were in type 2 diabetes, 1.4 to 3 g a day for 12 to 16 weeks) found no significant fall in HbA1c, with a difference of -0.10% (95% CI -1.05 to 0.85), and no significant change in cholesterol, BMI, blood pressure or triglycerides. Adverse events were more likely on reishi (RR 1.67, 95% CI 0.86 to 3.24), but the difference was not statistically significant and the events were not serious [5].

Wegovy lowers blood glucose and can cause hypoglycemia. The label reports increased hypoglycemia risk when Wegovy is used with insulin or an insulin secretagogue such as a sulfonylurea, and states that adding Wegovy to insulin has not been evaluated [6]. In the weight trial that enrolled adults with type 2 diabetes and a BMI of 27 or more, glucose below 54 mg/dL occurred in 6.2% of those on Wegovy 2.4 mg versus 2.5% on placebo, and risk was higher in people taking a sulfonylurea [6]. No extra glucose-lowering effect from reishi has been demonstrated [5].

Immune markers

In cancer patients, reishi has been linked to changes in some immune measurements. A Cochrane review of 5 randomized cancer trials, judged to be of poor methodological quality, found that reishi added to chemotherapy or radiotherapy raised CD3, CD4 and CD8 cell percentages by 3.91%, 3.05% and 2.02%. No trial recorded long-term survival, and the review found insufficient evidence to justify first-line use in cancer treatment [8]. Because reishi affects immune markers, a clash with immune-suppressing drugs is theoretical; no interaction study was found [8]. In the 16-person safety trial, CD56 cell count rose during 10 days of reishi and returned to baseline 10 days after the intake ended, a change that did not reach statistical significance in so small a group [7].

What the Wegovy label says to watch for

In pooled 68-week trials of Wegovy 2.4 mg in adults with obesity or overweight (2,116 on Wegovy, 1,261 on placebo), the common reactions were nausea 44% versus 16%, diarrhea 30% versus 16%, vomiting 24% versus 6%, constipation 24% versus 11% and abdominal pain 20% versus 10%; 6.8% versus 3.2% stopped treatment because of adverse reactions [6]. Severe gastrointestinal reactions occurred in 4.1% versus 0.9% [6]. Gallbladder disease was also more common: cholelithiasis 1.6% versus 0.7% and cholecystitis 0.6% versus 0.2% [6].

The Wegovy label describes persistent or severe abdominal pain, sometimes radiating to the back and sometimes with nausea or vomiting, as signs of possible acute pancreatitis, and says to discontinue Wegovy if pancreatitis is suspected [6]. It also says Wegovy is not recommended in people with severe gastroparesis [6].

Does reishi add anything to Wegovy for weight loss?

In the Cochrane review's pooled analysis of type 2 diabetes trials, reishi did not significantly change BMI [5]. For comparison, in STEP 1 — 1,961 adults with obesity or overweight and no diabetes, treated for 68 weeks — semaglutide 2.4 mg produced a mean weight change of -14.9% versus -2.4% on placebo [9].

Bottom line

The documented concerns sit on both sides: case reports of liver injury with reishi powder [1][2], and Wegovy's label warnings for severe gastrointestinal reactions, gallbladder disease and hypoglycemia with insulin or sulfonylureas [6]. The bleeding warning that circulates about reishi was not reproduced in a randomized trial in healthy volunteers [3].