Herb & supplement monograph

Toothed Clubmoss Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Toothed Clubmoss interacts with medications. The heart of this page is the interaction list — every drug Toothed Clubmoss is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Toothed Clubmoss is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Reviewed by licensed pharmacists Sourced from Natural Medicines
On this page

Toothed Clubmoss Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Toothed Clubmoss drug interaction appears low for most people, though it is worth attention if you take medicines that act on the same brain chemical it affects. None of the listed interactions are rated major, and all of them rest on animal or lab research rather than confirmed effects in people.

Interactions deserving the most attention

The concerns center on huperzine A, the active part of toothed clubmoss, which can boost a brain chemical called acetylcholine. Combining it with cholinergic drugs such as donepezil (Aricept) could in theory pile on similar effects and raise the chance of side effects. With anticholinergic drugs like atropine or benztropine, the two may work against each other, possibly making one or both less effective. These points matter most for people whose memory, movement, or nerve conditions depend on these medicines working steadily.

What the rest of the list means

The long list of interacting medications reflects just two broad drug groups, not hundreds of separate proven problems. So far, these predictions come from animal and lab studies, and none have been confirmed to cause meaningful changes in people.

Check your medications against Toothed Clubmoss

Based on HelloPharmacist’s Toothed Clubmoss interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Toothed Clubmoss

219 medications have a known interaction with Toothed Clubmoss, graded by severity. Select any drug for the full evidence-based detail.

2,830 drugs
AcepromazineAtravet› Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound› Acetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual› Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan HbrVicks Formula 44M Cough, Cold & Flu Relief› Acetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex› Acetaminophen, Chlorpheniramine, DextromethorphanCoricidin II Extra Strength Cold and Flu› Acetaminophen, Chlorpheniramine, Dextromethorphan HydrobromideCoricidin HBP Maximum Strength Flu› Acetaminophen, Chlorpheniramine, Dextromethorphan, PhenylpropanolamineMulti Symptom Cold Relief› Acetaminophen, Chlorpheniramine, Dextromethorphan, PseudoephedrineChildren's Tylenol Cold Plus Cough, Tylenol Cold Ex Strength› Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, SalicylamideRhinogesic GG› Acetaminophen, Chlorpheniramine, PhenylephrineAlka-Seltzer PLUS, Histex SR, Protid› Acetaminophen, Chlorpheniramine, Phenylephrine, SalicylamideRhinogesic, Rhinogesic JR› Acetaminophen, Chlorpheniramine, PhenylpropanolamineAlumadrine, Conex, Sinadrin Max Strength, Sinulin› Acetaminophen, Chlorpheniramine, Phenylpropanolamine, OpiumHista-Derfule› Acetaminophen, Chlorpheniramine, Phenylpropanolamine, PhenyltoloxamineNorel Plus› Acetaminophen, Chlorpheniramine, PseudoephedrineAlka-Seltzer PLUS Liquid Gels, Children's Tylenol Cold, Codimal, Comtrex, Extra Strength Tylenol Allergy Sinus, Lorsin +3 more› Acetaminophen, Codeine, DoxylamineMersyndol› Acetaminophen, Dextromethorphan, Doxylamine, PseudoephedrineVicks NyQuil› Acetaminophen, Dextromethorphan, Phenylpropanolamine, PyrilamineTheracaps› Acetaminophen, DiphenhydramineTylenol PM, Tylenol PM Ex Strength› Acetaminophen, Diphenhydramine, PseudoephedrineChildren's Tylenol Allergy, Cold Control, Contac Night Allergy Relief› Acetaminophen, Doxylamine, PseudoephedrineEx Strength Tylenol Sinus Nighttime› Acetaminophen, Pamabrom, PyrilamineMidol Max Strength PMS, Pamprin, Pamprin ES› Acetaminophen, Phenylephrine, ChlorpheniramineSuper Cold Tabs› AcetylcholineMiochol-E› Aclidinium BromideTudorza Pressair› Aclidinium Bromide, Formoterol Fumarate DihydrateDuaklir Pressair› Aerosphere Budesonide, Formoterol Fumarate, GlycopyrrolateBreztri› AmantadineGocovri, Osmolex ER, Symmetrel› Ambenonium ChlorideMytelase›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Toothed Clubmoss combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Toothed Clubmoss affects

Every type of medication (drug category) Toothed Clubmoss is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories Toothed Clubmoss interacts with
Anticholinergic DrugsCholinergic Drugs
Anticholinergic Drugs

In animal models, toothed clubmoss and huperzine A, an active constituent of toothed clubmoss, reversed cognitive deficits induced by scopolamine. Theoretically, concurrent use of anticholinergic drugs and toothed clubmoss might decrease the effectiveness of toothed clubmoss or the anticholinergic drug.
Some anticholinergic drugs include atropine, benztropine (Cogentin), biperiden (Akineton), procyclidine (Kemadrin), and trihexyphenidyl (Artane).

Likelihood Possible Evidence D
Cholinergic Drugs

Huperzine A, a constituent of toothed clubmoss, has demonstrated acetylcholinesterase inhibitory properties. Theoretically, concurrent use of toothed clubmoss with cholinergic drugs might have additive effects and increase the risk of cholinergic side effects.
Cholinergic drugs include bethanechol (Urecholine), donepezil (Aricept), echothiophate (Phospholine Iodide), edrophonium (Enlon, Reversol, Tensilon), neostigmine (Prostigmin), physostigmine (Antilirium), pyridostigmine (Mestinon, Regonol), succinylcholine (Anectine, Quelicin), and tacrine (Cognex).

Likelihood Possible Evidence D
Monograph

Toothed Clubmoss: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Toothed Clubmoss is a moss-like plant best known as the natural source of huperzine A, a compound studied mainly for memory and Alzheimer's disease. Some early research is promising, but the evidence is limited and the supplement is not well standardized or regulated, so quality between products varies. Because it can affect the nervous system, talk with a pharmacist or doctor before using it.

Toothed Clubmoss
Scientific name
Huperzia serrata
Family
Lycopodiaceae
Part used
Whole plant (above-ground parts), the source of huperzine A
Common forms
Capsules, tablets, powdered extracts; often sold as standardized 'huperzine A' supplements
People commonly use it for
  • Memory and cognitive support
  • Alzheimer's disease and dementia
  • General brain or 'nootropic' support
  • Inflammation and pain (traditional use)
  • Age-related memory loss

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallUse caution

May cause nervous-system and digestive side effects, and product quality varies widely.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full pregnancy detail
BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Toothed Clubmoss (Huperzia serrata) is a small, moss-like plant with spiky, toothed leaves. It grows in damp, shaded areas in parts of Asia and other regions. It has a long history in traditional Chinese medicine, where it is known as Qian Ceng Ta.

Today the plant is most famous as the natural source of a compound called huperzine A. Many supplements sold for memory or brain health are actually standardized huperzine A extracts made from this plant. People take it hoping to support memory and thinking, and it has been studied as a possible treatment for Alzheimer's disease.

How it works

The main active compound is huperzine A. It acts as a cholinesterase inhibitor, which means it slows the breakdown of acetylcholine, a brain chemical involved in memory and learning. This is similar to how some prescription Alzheimer's drugs work.

Laboratory and animal studies also suggest huperzine A may protect nerve cells from certain types of damage and may affect other brain receptors. These mechanisms are interesting, but much of this work is from cell or animal research and does not prove the same effects occur in people.

Effectiveness

Does Toothed Clubmoss work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 1 use evaluated
1 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For Toothed Clubmoss, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 1 condition — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Dementia
Rating & evidence shown verbatim from Natural Medicines

Meta-analyses of data from patients with mild dementia, cognitive impairment, or Alzheimer Disease suggest that huperzine A from toothed clubmoss might improve performance of activities of daily living, but the methodological quality of the data is very low.

Sources Ref 111333

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

Because huperzine A is biologically active and affects nerve signaling, it should be used with care. People with heart rhythm problems, slow heart rate, asthma, epilepsy, stomach ulcers, or urinary blockage should be especially cautious and check with a doctor first.

A major concern is product quality. Supplements are not tightly regulated, so the actual amount of huperzine A can differ from what the label says. Pregnant and breastfeeding women should avoid it because there is not enough safety information. It is also not recommended for children unless directed by a healthcare provider.

Always tell your pharmacist or doctor before starting this supplement, especially if you take medications or have a chronic health condition.

Side effects

Reported side effects are usually mild but can include nausea, stomach upset, diarrhea, sweating, blurred vision, dizziness, and restlessness. Because it boosts acetylcholine, it may also cause a slowed heart rate, muscle twitching, or excess saliva in some people.

Higher doses raise the risk of these effects. Stop using it and seek medical care if you have a very slow or irregular heartbeat, trouble breathing, severe vomiting, or fainting.

Toothed Clubmoss: Reported Adverse Effects

Documented safety reports on Toothed Clubmoss from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

No adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.

Orally, huperzine A, a constituent of toothed clubmoss, can cause dizziness, nausea, and sweating.

  1. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.
Reports by condition
Nausea and vomiting Gastrointestinal

Orally, huperzine A, a constituent of toothed clubmoss, can cause nausea.

  1. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.
Vertigo Neurologic/CNS

Orally, huperzine A, a constituent of toothed clubmoss, can cause dizziness and sweating.

  1. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no official, standardized dose for Toothed Clubmoss. Most products are labeled by their huperzine A content, often in very small amounts measured in micrograms. Because potency varies between brands, the safest approach is to follow the product label and not exceed it.

Start low and check with a pharmacist or doctor before use, especially if you are older, take other medicines, or have heart, lung, or stomach conditions. Avoid combining different supplements that contain huperzine A.

Pregnancy & Breastfeeding

Toothed Clubmoss & Pregnancy

Insufficient reliable information

Insufficient reliable information available; avoid using.

Toothed Clubmoss & Breastfeeding

Insufficient reliable information

Insufficient reliable information available; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 4 references that drive our Toothed Clubmoss monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Budavari S, ed. The Merck Index. 12th ed. Whitehouse Station, NJ: Merck & Co., Inc., 1996.
  2. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.
  3. Ohba T, Yoshino Y, Ishisaka M, et al. Japanese Huperzia serrata extract and the constituent, huperzine A, ameliorate the scopolamine-induced cognitive impairment in mice. Biosci Biotechnol Biochem. 2015;79(11):1838-44.
  4. Sawangjit R, Chuenchom C, Sanverm T, et al. Efficacy and safety of herbal medicine on dementia and cognitive function: An umbrella review of systematic reviews and meta-analysis. Phytother Res 2023. PubMed
Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Toothed Clubmoss

48 brands in our database make a supplement containing Toothed Clubmoss.

Product directory

Supplement products with Toothed Clubmoss

101 products in our database contain Toothed Clubmoss. Open any to see its full ingredient list and every drug interaction we check.

F-Bomb Cat Scratch Fever by 'Merica Labz Powder 10.65 Ounce(s) · 302 Gram(s) View ingredients & interactions F-Bomb F Your Feelings by 'Merica Labz Powder 12.28 Ounce(s) · 348 Gram(s) View ingredients & interactions F-Bomb Sour Gummy Snakes by Merica Labz Powder 13.1 Ounce(s) · 370 Gram(s) View ingredients & interactions F-Bomb Upside Down Pineapple by 'Merica Labz Powder 10.94 Ounce(s) · 310 Gram(s) View ingredients & interactions Forebrain by Force Factor Capsule 30 Capsule(s) View ingredients & interactions Genius Burn by The Genius Brand Capsule 60 Veggie Capsule(s) View ingredients & interactions Genius Pre Grape Limeade by The Genius Brand Powder 11.92 Ounce(s) · 338 Gram(s) View ingredients & interactions Ginkgo Smart by Irwin Naturals Softgel Capsule 60 Liquid Soft-Gel(s) View ingredients & interactions Ginkgo Smart by Irwin Naturals Softgel Capsule 60 Liquid Soft-Gel(s) View ingredients & interactions Harness Evolution Orange Julian by Arms Race Nutrition Powder 17.3 Ounce(s) · 490 Gram(s) View ingredients & interactions Harness Lemon Rush by ARN Arms Race Nutrition Liquid 12 Fluid Ounce(s) · 355 mL View ingredients & interactions Harness Pre-Workout Big Apple by ARN Arms Race Nutrition Liquid 12 Fluid Ounce(s) · 355 mL View ingredients & interactions Harness Rainbow Sherbet by ARN Arms Race Nutrition Liquid 12 Fluid Ounce(s) · 355 mL View ingredients & interactions Harness Venice Beach by ARN Arms Race Nutrition Liquid 12 Fluid Ounce(s) · 355 mL View ingredients & interactions Huperzine-A by Absonutrix Liquid 4 Fluid Ounce(s) · 118 mL View ingredients & interactions Ignition Switch ICEE Blue Raspberry by Axe & Sledge Supplements Powder 210 Gram(s) · 7.41 Ounce(s) View ingredients & interactions Lipo-6 Hardcore by Nutrex Research Capsule 60 Capsule(s) View ingredients & interactions Loco Sucka-Free Tea by MyoBlox Powder 624.6 Gram(s) · 22.03 Ounce(s) View ingredients & interactions Loco Watermelon Candy by MyoBlox Powder 11.64 Ounce(s) · 329 Gram(s) View ingredients & interactions Mach 9 Rocket Ice by Nutra Innovations Powder 204 Gram(s) · 7.19 Ounce(s) View ingredients & interactions Maniac Apple Ambush by Anabolic Warfare Powder 13.4 Ounce(s) · 380 Gram(s) View ingredients & interactions Maniac Fruit Explosion by Anabolic Warfare Powder 13.76 Ounce(s) · 390 Gram(s) View ingredients & interactions Maniac Guerilla Grape by Anabolic Warfare Powder 13.69 Ounce(s) · 388 Gram(s) View ingredients & interactions Memory Power+ by Efficient Laboratories Tablet Or Pill 40 Tablet(s) View ingredients & interactions
Pharmacist Counseling Corner

Toothed Clubmoss: Common Questions

What is Toothed Clubmoss used for, and does it work?
People use Toothed Clubmoss for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Toothed Clubmoss interact with prescription medications?
Yes. We list 219 medications with a known interaction with Toothed Clubmoss. Use the checker above to see how Toothed Clubmoss interacts with a specific drug.
How are Toothed Clubmoss interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Toothed Clubmoss with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Toothed Clubmoss interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
What is Toothed Clubmoss used for?
It is mainly used for memory and brain support, and it is the natural source of huperzine A, which has been studied for Alzheimer's disease. The evidence for these uses is limited and not conclusive.
Is Toothed Clubmoss the same as huperzine A?
Not exactly. Huperzine A is one active compound found in the plant. Many supplements are standardized huperzine A extracts made from Toothed Clubmoss.
Is Toothed Clubmoss safe to take?
It may cause nervous-system and digestive side effects, and product quality varies a lot. It is best to use it only under the guidance of a pharmacist or doctor.
Can I take it during pregnancy or breastfeeding?
No. There is not enough safety information, so it is best to avoid Toothed Clubmoss and huperzine A while pregnant or breastfeeding.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Keep exploring

Products that contain Toothed Clubmoss

A rotating sample of real supplements in our database that list Toothed Clubmoss — open any to see its full ingredients and every drug interaction we check.

See all 101 products with Toothed Clubmoss →
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