Major interaction on record — check this product against your medications before combining. Based on 2 of 9 ingredients. Check your meds →
Dietary supplement

Flexlyn Ingredients & Drug Interactions

by Princess Lifestyle

Flexlyn label
See full label image
Capsule Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Flexlyn against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Flexlyn is a dietary supplement by Princess Lifestyle with 9 active ingredients. Its ingredients are commonly taken for menopause symptoms, menstrual cramps and irregular periods, premenstrual syndrome (pms).Based on those ingredients, 416 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Rehmannia glutinosa, Dong-Quai. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Flexlyn by Princess Lifestyle

Ask about any prescription or over-the-counter medication and we check it for interactions with Flexlyn by Princess Lifestyle — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Flexlyn by Princess Lifestyle

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 30, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 9 active ingredients.
  • “Proprietary Blend” is a proprietary blend — the label gives one combined amount (1,000 mg) without saying how much of each component you get.

Flexlyn contains 9 ingredients in total. The active ones include a proprietary blend—a combination of traditional botanical ingredients—along with dong quai (also called Angelica sinensis), rehmannia glutinosa, and six others: Oriental Ginseng, Eucommia, Pubescent Angelica, Loranthus, Cyathula, and Sichuan Lovage.

Each is included for its traditional use in herbal medicine. The capsule itself is made from gelatin, dicalcium phosphate, and cellulose—all inactive fillers and binders.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: Supports joint function and kidney health.
  • We looked for evidence on: Rheumatoid arthritis (RA), Chronic kidney disease (CKD), Dysmenorrhea, Menopausal symptoms, Premenstrual syndrome (PMS), Joint flexibility — and 2 related terms.
  • The strongest evidence on file: Rehmannia is rated "Possibly Effective" for Chronic kidney disease (CKD) (Natural Medicines).
  • Also on file: Dong Quai is rated "Insufficient Reliable Evidence To Rate" for Menopausal symptoms, Premenstrual syndrome (PMS), Rheumatoid arthritis (RA), Dysmenorrhea, and more.
  • Also on file: Rehmannia is rated "Insufficient Reliable Evidence To Rate" for Rheumatoid arthritis (RA).

The evidence for what Flexlyn does isn't established in the data we hold. Dong quai has been studied for iron deficiency anemia, osteoporosis, heart disease, migraines, and eczema, but the evidence for all of these is insufficient to rate.

Rehmannia shows possibly effective evidence for chronic kidney disease but insufficient evidence for anemia, atopic disease, osteoporosis, diabetes, and diabetic kidney disease. If you're considering this product for a specific health concern, talk it over with your doctor or pharmacist.

The evidence, ingredient by ingredient Dong Quai Rehmannia

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Dong quai is generally well tolerated when taken by mouth; the most common side effects are burping and flatulence. However, it can increase bleeding risk and cause skin sensitivity to sunlight, so use it with care if you're in the sun.

The safety data advises against taking dong quai during pregnancy because it may stimulate the uterus and affect bleeding, and there isn't enough safety information to use it while breastfeeding. Rehmannia is used in traditional medicine but has limited human safety data and quality varies between products.

There isn't enough safety information to use rehmannia during pregnancy or while breastfeeding, so avoid it in both situations.

Side effects, ingredient by ingredient Dong Quai Rehmannia

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Dong Quai, Rehmannia.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications.
  • For scale: 416 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking Flexlyn, check with your doctor or pharmacist if you take warfarin or other blood thinners—dong quai raises bleeding risk significantly. Also double-check if you're on other anticoagulant or antiplatelet drugs like aspirin, estrogen-based medications (including hormone replacement therapy), blood pressure medications, or diabetes drugs, as rehmannia and dong quai may affect how these work.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with some supporting evidence for its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

Flexlyn is a multi-ingredient herbal supplement with interactions you'll need to check carefully, especially if you take blood thinners, blood pressure drugs, diabetes medications, or hormone therapy. If you take any prescription medication—or if you're pregnant or breastfeeding—talk with your doctor or pharmacist before starting this product to make sure it's right for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 9 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jun 16, 2022.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Flexlyn, straight from the product label.

Brand Princess Lifestyle
Net contents 100 Capsule(s)
Market status On market
Date entered into DSLD Jun 16, 2022
DSLD ID 268453
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Flexlyn by Princess Lifestyle, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
50
IngredientAmount% DV
Proprietary Blend1000 mg--
Oriental Ginseng0 NP--
Eucommia0 NP--
Pubescent Angelica0 NP--
Loranthus0 NP--
Cyathula0 NP--
Sichuan Lovage0 NP--
Dong-Quai0 NP--
Rehmannia glutinosa0 NP--
Corydalis0 NP--

Other ingredients: Dicalcium Phosphate, Gelatin, Cellulose

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formulation

Flexlyn is the result of many years of dedicated study of natural herbal formulas. It contains very high quality concentrated natural herbal extracts with functions to help eliminate cold and damp, tonify the kidney Yin and Yang, warm up the channels and collaterals, activate Qi and blood circulation.

Manufactured in a certified food processor and quality assured facility.

Supports joint function

No sugar, no starch, no artificial colors, no artificial flavors, sodium free, no wheat, no gluten, no corn, no soy, no dairy, yeast free.

Suggested/Recommended/Usage/Directions

Suggested usage: As a dietary supplement, take 1 capsule, 3 times a day with a glass of warm water.

Storage

Caution: Store in a cool and dry place.

Precautions

Keep out of reach of children.

Do not use if pregnant or nursing.

FDA Statement of Identity

Herbal Dietary Supplement

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Flexlyn by Princess Lifestyle label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Flexlyn label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Flexlyn by Princess Lifestyle

These are the 9 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Servings per container50 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Proprietary Blend

1000 mg per serving
  • › Oriental Ginseng
  • › Eucommia
  • › Pubescent Angelica
  • › Loranthus
  • › Cyathula
  • › Sichuan Lovage
  • › Dong-Quai
  • › Rehmannia glutinosa
  • › Corydalis

Other (inactive) ingredients: Dicalcium Phosphate, Gelatin, Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

Flexlyn by Princess Lifestyle Drug Interactions

Want to check YOUR meds against Flexlyn?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
416Drugs
2 Major 414 Moderate

Ingredients driving the most interactions

Rehmannia glutinosa 258
Dong-Quai 163

Individual Drug Interactions

The ingredients in Flexlyn interact with 416 drugs. Click any drug to see the details.

2 of the 9 ingredients in Flexlyn interact with drugs. Each result below shows which ingredient is responsible. Rehmannia glutinosa Dong-Quai

Each ingredient & the kinds of drugs it affects

For each ingredient in Flexlyn with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Rehmannia glutinosa2 drug types · 258 drugs

Antidiabetes Drugs

Theoretically, rehmannia might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that rehmannia may have hypoglycemic effects.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, rehmannia might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research shows that rehmannia may have hypotensive effects. Laboratory research shows that formulations of dried and processed rehmannia root inhibit angiotensin-converting enzyme (ACE).

Likelihood Possible Evidence D
Rehmannia glutinosa full monograph & interactions

Dong-Quai3 drug types · 163 drugs

Warfarin (Coumadin)

Dong quai may increase the risk of bleeding when used with warfarin.
Case reports suggest that concomitant use of dong quai with warfarin can increase the anticoagulant effects of warfarin and increase the risk of bleeding. In one case, after 4 weeks of taking dong quai 565 mg once or twice daily, the international normalized ratio (INR) increased to 4.9. The INR normalized 4 weeks after discontinuation of dong quai.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, dong quai may increase the risk of bleeding when used with anticoagulant or antiplatelet drugs; however, research is conflicting.
Animal studies suggest that dong quai has antithrombin activity and inhibits platelet aggregation due to its coumarin components. Additionally, some case reports in humans suggest that dong quai can increase the anticoagulant effects of warfarin. However, clinical research in healthy adults shows that taking 1 gram of dong quai root daily for 3 weeks does not significantly inhibit platelet aggregation or cause bleeding. Until more is known, use dong quai with caution in patients taking antiplatelet/anticoagulant drugs.

Likelihood Possible Evidence D
Estrogens

Theoretically, dong quai may reduce the effects of estrogens.
Dong quai has estrogenic effects. Theoretically, concomitant use of large amounts of dong quai might interfere with hormone replacement therapy due to competition for estrogen receptors.

Likelihood Possible Evidence D
Dong-Quai full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Flexlyn, from the product label.

Princess Lifestyle

See all Princess Lifestyle products
Name
Princess Lifestyle, LLC
City
Baldwin Park
State
CA
Pharmacist Counseling Corner

Flexlyn by Princess Lifestyle: Common Questions

Does Flexlyn by Princess Lifestyle interact with any medications?
Yes. Based on its ingredients, Flexlyn has a known interaction with 416 medications, including 2 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Flexlyn contains 9 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take Flexlyn if I'm on warfarin?
No, not without talking to your doctor first. Dong quai in this product can increase warfarin's blood-thinning effect and raise your bleeding risk significantly. Your doctor needs to know before you take it.
Is Flexlyn safe during pregnancy?
The safety data advises against it. Dong quai may stimulate the uterus and affect bleeding during pregnancy. Talk with your doctor or pharmacist about whether this product is right for you.
Can I take this while breastfeeding?
There isn't enough safety information for dong quai or rehmannia while breastfeeding, so both are best avoided. Check with your doctor or pharmacist for personalized advice.
What's the most common side effect?
Burping and flatulence are the most common side effects reported with dong quai when taken by mouth. Some people have also reported allergic reactions like asthma or nasal inflammation.
Can Flexlyn lower my blood sugar if I take diabetes medication?
Possibly. Rehmannia in this product may lower blood sugar, so there's a theoretical risk of blood sugar dropping too low if you're on diabetes drugs. Your doctor or pharmacist should review this before you start.
Will Flexlyn affect my hormone replacement therapy?
Dong quai has estrogenic effects and may theoretically interfere with how your hormone therapy works. Talk with your doctor or pharmacist to make sure it's safe for you to use together.

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

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Flexlyn label
Go deeper

The Full Monographs Behind Flexlyn’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Dong Quai

Interacts with 163 drugs

Dong Quai is a traditional Chinese herb often called "female ginseng" and is mostly used for menstrual and menopausal complaints. High-quality scientific evidence that it works for these use...

Read the full Dong Quai monograph → Herb & supplement monograph

Rehmannia

Interacts with 258 drugs

Rehmannia is a root used for centuries in Traditional Chinese Medicine, often to 'tonify' the kidneys and support energy or blood health. Human evidence for most modern uses is limited, so i...

Read the full Rehmannia monograph →
Sources

Sources & How We Checked

Flexlyn's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 22 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Dong Quai 19 references
  1. Hirata JD, Swiersz LM, Zell B, et al. Does dong quai have estrogenic effects in postmenopausal women? A double-blind, placebo-controlled trial. Fertil Steril 1997;68:981-6. PubMed
  2. Page RL II, Lawrence JD. Potentiation of warfarin by dong quai. Pharmacotherapy 1999;19:870-6. PubMed
  3. Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000;57:1221-7. DOI
  4. Eagon PK, Elm MS, Hunter DS, et al. Medicinal herbs: modulation of estrogen action. Era of Hope Mtg, Dept Defense; Breast Cancer Res Prog, Atlanta, GA 2000;Jun 8-11.
  5. Dr. Duke's Phytochemical and Ethnobotanical Databases. Available at: http://www.ars-grin.gov/duke/.
  6. Amato P, Christophe S, Mellon PL. Estrogenic activity of herbs commonly used as remedies for menopausal symptoms. Menopause 2002;9:145-50. PubMed
  7. Shi M, Chang L, He G. [Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus]. Zhongguo Zhong Yao Za Zhi 1995;20:173-5, 192.
  8. Hoult JR, Paya M. Pharmacological and biochemical actions of simple coumarins: natural products with therapeutic potential. Gen Pharmacol 1996;27:713-22.. PubMed
  9. Cheong JL, Bucknall R. Retinal vein thrombosis associated with a herbal phytoestrogen preparation in a susceptible patient. Postgrad Med J 2005;81:266-7.. PubMed
  10. Chang CJ, Chiu JH, Tseng LM, et al. Modulation of HER2 expression by ferulic acid on human breast cancer MCF7 cells. Eur J Clin Invest 2006;36:588-96. PubMed
  11. Chuang CH, Doyle P, Wang JD, et al. Herbal medicines used during the first trimester and major congenital malformations: an analysis of data from a pregnancy cohort study. Drug Saf 2006;29:537-48. PubMed
  12. Lau CBS, Ho TCY, Chan TWL, Kim SCF. Use of dong quai (Angelica sinensis) to treat peri- and postmenopausal symptoms in women with breast cancer: is it appropriate? Menopause 2005;12:734-40.
  13. Ellis GR, Stephens MR. Untitled (photograph and a brief case report). BMJ 1999;319:650.
  14. Nambiar, S., Schwartz, R. H., and Constantino, A. Hypertension in mother and baby linked to ingestion of Chinese herbal medicine. West J Med 1999;171(3):152.
  15. Lee, S. K., Cho, H. K., Cho, S. H., Kim, S. S., Nahm, D. H., and Park, H. S. Occupational asthma and rhinitis caused by multiple herbal agents in a pharmacist. Ann.Allergy Asthma Immunol. 2001;86(4):469-474. PubMed
  16. Xu, J. and Li, G. [Observation on short-term effects of Angelica injection on chronic obstructive pulmonary disease patients with pulmonary hypertension]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2000;20(3):187-189.
  17. Scott, G. N. and Elmer, G. W. Update on natural product--drug interactions. Am J Health Syst.Pharm 2-15-2002;59(4):339-347. PubMed
  18. Circosta, C., Pasquale, R. D., Palumbo, D. R., Samperi, S., and Occhiuto, F. Estrogenic activity of standardized extract of Angelica sinensis. Phytother.Res. 2006;20(8):665-669.
  19. Fung FY, Wong WH, Ang SK, et al. A randomized, double-blind, placebo- controlled study on the anti-haemostatic effects of Curcuma longa, Angelica sinensis and Panax ginseng. Phytomedicine. 2017;32:88-96. PubMed

See these in context on the Dong Quai monograph →

Rehmannia 3 references
  1. Zhang R, Zhou J, Jia Z, et al. Hypoglycemic effect of Rehmannia glutinosa oligosaccharide in hyperglycemic and alloxan-induced diabetic rats and its mechanism. J Ethnopharmacol 2004;90:39-43. PubMed
  2. Zhang RX, Li MX, Jia ZP. Rehmannia glutinosa: review of botany, chemistry and pharmacology. J Ethnopharmacol 2008;117(2):199-214. PubMed
  3. Chao CH, Hsu JL, Chen MF, et al. Anti-hypertensive effects of Radix Rehmanniae and its active ingredients. Nat Prod Res. 2020;34(11):1547-1552.

See these in context on the Rehmannia monograph →

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

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