Mushroom Supplements During Pregnancy and Breastfeeding: Evidence Gaps and Caution

Quick Answer

No functional mushroom supplement — lion’s mane, reishi, cordyceps, chaga, turkey tail, or maitake — has been studied for safety in pregnant or breastfeeding people. There is no dosing data, no birth outcome data, and no data on how these compounds pass into breast milk. Because of this evidence gap, the standard guidance for any unstudied supplement during pregnancy or lactation is to talk with your ob-gyn or another qualified clinician before use.

Stop and Call Your Provider If This Happens

If you have already taken a mushroom supplement while pregnant or breastfeeding and notice a rash, hives, swelling, trouble breathing, unusual bleeding, severe stomach pain, or a fast heartbeat, stop the product and contact your healthcare provider or seek emergency care right away. Bring the product label with you so your provider can see exactly what was in it.

Why the Evidence Gap Exists

Pregnant and breastfeeding people are almost always excluded from supplement research studies. This is standard practice across the supplement industry, not something specific to mushroom products. It means companies cannot ethically test these ingredients on pregnant volunteers, so safety data simply does not exist yet for most botanicals, including functional mushrooms.

The American College of Obstetricians and Gynecologists (ACOG) publishes patient guidance on nutrition during pregnancy covering nutrients such as folic acid, iron, calcium, vitamin D, choline, omega-3 fatty acids, B vitamins, and vitamin C. That guidance focuses on food and standard prenatal nutrients and does not address functional mushroom products, which reflects how new and understudied this supplement category is in mainstream prenatal care.

The National Institutes of Health Office of Dietary Supplements maintains a pregnancy-focused fact sheet covering vitamins, minerals, choline, omega-3 fatty acids, and a small number of botanicals for which research is available. Functional mushroom species are not among the ingredients with established pregnancy safety data in that resource.

Separately, a fact sheet from the MotherToBaby network, hosted on the National Library of Medicine’s NCBI Bookshelf, notes that many herbal supplements have not been evaluated for pregnancy or breastfeeding use at all, and that herbal products can carry added risks: some contain contaminants such as lead, arsenic, or mercury, some contain ingredients not listed on the label, and liquid tinctures or extracts can contain alcohol, which should be avoided during pregnancy.

What This Means for Common Mushroom Products

Below is a plain-language snapshot of where the evidence stands. “No pregnancy or lactation safety data” means researchers have not published human studies confirming safe use in these groups — not that a problem has been found, and not that the product is confirmed safe either.

• Lion’s Mane (Hericium erinaceus): Studied mainly in non-pregnant adults. No pregnancy or lactation safety data. See our Lion’s Mane research library page for the general evidence base.
• Reishi (Ganoderma lucidum): Long history of traditional use, but modern clinical research is limited to non-pregnant adults. No pregnancy or lactation safety data. See our Reishi research library page.
• Cordyceps: No pregnancy or lactation safety data. Marketed mainly for energy and athletic performance in general-population studies.
• Chaga, Turkey Tail, and Maitake: No pregnancy or lactation safety data in any of these species.

Format matters too. Tinctures and liquid extracts can contain alcohol; capsules and powders do not carry that specific risk, and extraction method or concentration is rarely standardized across brands. Our guide to capsules, gummies, tinctures, and coffee formats explains these differences in more detail.

Extra Caution Groups

Some situations call for even more caution before considering any dietary supplement, including functional mushrooms:

• People who are pregnant with twins or multiples
• People managing gestational diabetes or blood sugar concerns, since some mushroom species are marketed around blood sugar support
• People taking prescription medications, since herb-drug interactions have not been studied for most functional mushroom species
• People with a mushroom or mold allergy
• People who are breastfeeding a newborn or premature infant

A Simple Decision Path

1. Are you pregnant or breastfeeding, or planning to become pregnant soon? If yes, continue.
2. Have you talked with your OB-GYN, midwife, or another qualified clinician about this specific product? If not, that is the next step before use.
3. Does your provider clear the product? Follow their guidance, including on dose and timing.
4. If your provider advises against it, or you have not yet asked, the evidence-based choice is to wait until after pregnancy and breastfeeding, when more is known.

Checklist Before You Consider Any Mushroom Supplement

• I have talked with my ob-gyn, midwife, or pharmacist about this exact product
• I have shared the full ingredient label, not just the mushroom species name
• I know whether the product is a capsule, powder, or liquid tincture
• I have checked for third-party testing or a certificate of analysis for contaminants
• I understand there is no published pregnancy or lactation safety data for this ingredient

Frequently Asked Questions

Is it safe to take lion’s mane or reishi while pregnant?

There is no published research confirming safety for either ingredient during pregnancy. This does not mean harm has been proven, only that the studies have not been done. Talk with your OB-GYN before using either one.

Can functional mushroom compounds pass into breast milk?

This has not been studied for lion’s mane, reishi, cordyceps, chaga, turkey tail, or maitake. Because researchers do not yet know how these compounds transfer into breast milk, caution is the standard recommendation.

Are mushroom coffees and blends different from mushroom capsules for pregnancy safety?

The delivery format changes convenience and, in the case of tinctures, whether alcohol is present, but it does not create pregnancy safety data that would otherwise be absent. Every format still carries the same evidence gap.

What should I do if I already took a mushroom supplement before I knew I was pregnant?

Contact your ob-gyn or midwife and tell them exactly which product you took and how much. This information helps them give you accurate, personalized guidance, and there is generally no benefit to withholding it.

Educational Disclaimer

This article is for general education only and is not medical advice. It does not diagnose, treat, or prevent any condition, and it is not a substitute for care from a qualified healthcare provider. Always talk with your OB-GYN, midwife, or another qualified clinician before starting, stopping, or changing any supplement during pregnancy or breastfeeding. For more on how we evaluate research and disclose our commercial relationships, see our Research Standards and Disclosure page.