No one can say with confidence that a specific medicinal mushroom supplement is safe during pregnancy or breastfeeding, because that research has not been done. Almost no clinical trials of reishi, lion’s mane, cordyceps, chaga, turkey tail, or other mushroom extracts have included pregnant or breastfeeding people. The general guidance from health authorities is to talk with your obstetric provider before starting any dietary supplement while pregnant or nursing, since many supplements have not been tested in these groups at all.
This is different from eating cooked culinary mushrooms, like white button, shiitake, or oyster mushrooms, as part of a normal meal. Culinary mushrooms have a long history of safe use as food. Concentrated mushroom supplements are a separate category, made with extraction methods and doses that go beyond what a person eats in a meal, and that difference matters for safety evidence.
Culinary Mushrooms vs. Concentrated Supplements: Why the Distinction Matters
The National Center for Complementary and Integrative Health (NCCIH) treats food-level use of a substance and concentrated supplement use as separate questions, because they are not equivalent for safety purposes. A serving of cooked shiitake or oyster mushroom delivers a food-level amount of naturally occurring compounds. A capsule, powder, or tincture labeled as a mushroom extract can concentrate specific compounds, such as beta-glucans or triterpenes, at levels well above food amounts.
Concentrated supplements are also processed differently from whole food. Extraction methods, solvents, and standardization to a particular compound change what actually ends up in the product. A study on one specific extract cannot be assumed to apply to a different product, even when both are marketed under the same mushroom name.
Here is how the three categories compare on pregnancy and breastfeeding evidence:
- Culinary mushrooms eaten as food (white button, shiitake, oyster, maitake, cooked and store-bought): long history of food use; ordinary food-safety practices apply, such as thorough cooking and buying from reputable sources.
- Concentrated mushroom supplements (capsules, powders, tinctures, or extracts of reishi, lion’s mane, cordyceps, chaga, turkey tail, and similar species): little to no human safety data specific to pregnancy or breastfeeding exists.
- Wild-harvested mushrooms: carry a separate poisoning risk unrelated to supplement safety. Never treat wild mushroom identification as a supplement safety question.
Why the Safety Data Gap Exists
Clinical trials of medicinal mushroom extracts, including the ones with the strongest human evidence, such as PSK (polysaccharide-K) from turkey tail used alongside cancer treatment in Japan, have been conducted in adult populations and have not specifically studied pregnant or breastfeeding participants. The National Cancer Institute’s patient summary on medicinal mushrooms describes PSK as an approved cancer treatment product in Japan with few reported side effects in the populations studied, and it distinguishes this human clinical evidence from earlier laboratory and animal research that tested the same compounds before human trials began.
Excluding pregnant and breastfeeding people from most supplement and drug research is standard practice, not something specific to mushrooms. Researchers exclude these groups because a substance could theoretically affect a developing fetus or infant in ways adult-only studies would not detect, and because studying pregnant or breastfeeding people raises additional ethical considerations.
The result is a genuine evidence gap. It does not mean mushroom supplements are known to be dangerous during pregnancy or breastfeeding. It means the studies needed to say they are safe simply have not been done.
What “No Data” Means in Practice
When a mushroom species page describes a supplement as generally well tolerated in adult studies, that finding almost always comes from research in non-pregnant, non-breastfeeding adults. It is not a statement about pregnancy or lactation safety. Readers should not extend “well tolerated in adults” to pregnant or breastfeeding people unless a source specifically studied those groups, which none currently reviewed here do.
This follows the same evidence-hierarchy principle used across mushroom research generally: findings from one population, dose, or product cannot be assumed to transfer to a different population, dose, or product. For more on how to weigh different types of mushroom evidence, see our guide to how in-vitro, animal, and human study evidence differs.
Species With Theoretical Concerns Worth Knowing About
No mushroom supplement has confirmed pregnancy or breastfeeding safety data, but a few species carry theoretical concerns worth raising with a clinician:
- Reishi (Ganoderma lucidum): Contains triterpene compounds and has been studied in adults for effects related to blood clotting and blood pressure. Because pregnancy already involves changes to clotting factors, a supplement with theoretical effects on clotting or blood pressure deserves a specific conversation with an obstetric provider before use. See our reishi mushroom research profile for what the human evidence does and does not show.
- Cordyceps: Published laboratory and animal studies have examined effects on reproductive hormones, including testosterone production in male mice. Animal-model findings do not establish an effect in pregnant humans, but they are part of why this species has not been studied or recommended for use in pregnancy. See our cordyceps safety and research overview for the human evidence base.
- Lion’s Mane: Human trial evidence is limited to non-pregnant adult populations, mostly examining cognitive and mood outcomes over defined study periods. There is no pregnancy- or lactation-specific data. See our lion’s mane research profile.
These are theoretical, precautionary points based on the type of compounds involved and the populations studied, not documented harms in pregnant or breastfeeding people. No published human study has reported that any of these mushroom supplements caused harm in pregnancy or lactation, but the absence of a reported harm is not the same as evidence of safety, because so few pregnant or breastfeeding people have been included in mushroom supplement research.
Standard Precautionary Guidance
NCCIH advises that many dietary supplements have not been tested in pregnant women, nursing mothers, or children, and recommends discussing any supplement with a health care provider before use in these groups. NCCIH also notes that the FDA is not authorized to review dietary supplements for safety or effectiveness before they reach the market, and can only take action against an unsafe or mislabeled product after it is already for sale.
Obstetric care organizations, including the American College of Obstetricians and Gynecologists (ACOG), direct patients toward talking with their obstetrician-gynecologist before starting any new supplement during pregnancy, since an individual’s health history, medications, and pregnancy course all affect whether a given product carries additional risk. This guidance is not specific to mushrooms. It reflects how these organizations treat unregulated supplement categories generally when pregnancy-specific safety trials do not exist.
Decision Path: Thinking Through Mushroom Supplement Use in Pregnancy or Breastfeeding
- Is this a culinary mushroom eaten as food, cooked and from a reputable food source? Standard food-safety practices apply, and this is different from supplement use.
- Is this a concentrated supplement, such as a capsule, powder, tincture, or extract? Treat it as a substance without pregnancy or breastfeeding safety data, regardless of species.
- Do you take any prescription medicine, especially blood thinners, blood pressure medicine, or immune-affecting drugs? Mention every supplement you are considering to your prescriber, since interaction data is often even more limited than general safety data.
- Have you talked with your obstetric provider or midwife about this specific product? A clinician who knows your health history and pregnancy course is the only person positioned to weigh in on your individual situation.
- Do not start, stop, or substitute any supplement for medical care without that conversation first.
Extra-Caution Situations
A few situations call for particular caution and a clinician conversation before considering any mushroom supplement:
- High-risk pregnancy, including pregnancies with clotting disorders, blood pressure conditions such as preeclampsia, or gestational diabetes
- Use of prescription blood thinners, blood pressure medicine, immunosuppressants, or chemotherapy
- A history of mushroom or mold allergy
- Premature infants or infants with underlying health conditions, when a supplement is being considered during breastfeeding
- Any plan to substitute a supplement for prenatal vitamins, prescribed medicine, or recommended prenatal care
For general supplement-related cautions that apply outside of pregnancy as well, see our mushroom safety and interactions guide and our overview of quality and testing standards for mushroom supplements, since sourcing and product quality are separate concerns from the pregnancy-specific evidence gap covered here.
Frequently Asked Questions
Is it safe to eat cooked culinary mushrooms, like shiitake or button mushrooms, during pregnancy? Cooked culinary mushrooms eaten as food are different from concentrated supplements and have a long history of food use. Ordinary food-safety practices, such as thorough cooking and buying from reputable sources, apply the same way they do to other foods during pregnancy. This article focuses on concentrated mushroom supplements, which carry a separate and much less established evidence picture.
Has any mushroom supplement been proven unsafe in pregnancy? No published human research has documented that mushroom supplements are unsafe in pregnancy, but that is because pregnant people have largely been excluded from the studies, not because safety has been established. Theoretical concerns exist for specific species, discussed above, based on the type of compounds studied.
Can I keep taking a mushroom supplement I started before I found out I was pregnant? This is a question for your obstetric provider, who can review the specific product, your health history, and how far along you are. Do not decide to continue or stop a supplement based on general information alone.
Are mushroom supplements regulated for pregnancy safety before they are sold? No. In the United States, dietary supplements, including mushroom extracts, are not required to undergo pregnancy-specific safety testing or FDA approval before sale. Manufacturers are responsible for safety and accurate labeling, but the FDA does not routinely review products before they reach store shelves.
Evidence Limits
This article reflects the current absence of pregnancy- and breastfeeding-specific human research on medicinal mushroom supplements, based on NCCIH’s general dietary supplement guidance and the National Cancer Institute’s patient summary of medicinal mushroom research. It does not draw on any pregnancy-specific clinical trial of a mushroom supplement, because none of substance currently exists in the published literature reviewed for this piece. The species-specific theoretical concerns noted above are based on general pharmacology and preclinical research described in our individual species profiles, not on documented pregnancy outcomes.
Educational Disclaimer
This article is for general educational purposes only and is not medical advice. It does not diagnose any condition, recommend any supplement, or establish that any product is safe or effective during pregnancy or breastfeeding. Pregnancy and breastfeeding involve individual health considerations that only a qualified clinician who knows your full history can evaluate. Always talk with your obstetrician-gynecologist, midwife, or other qualified health care provider before starting, stopping, or changing any supplement, medicine, or treatment during pregnancy or while breastfeeding.