Purple nutsedge (Cyperus rotundus)

Also called Cyperus rotundus, nut grass, nutgrass, musta, nagarmotha, Cyperi rhizoma.

Best grade C across 5 graded outcomes Botanical Last checked Oct 21, 2026

The short answer

From 8 sources

Purple nutsedge is a sedge whose rhizome is used in Ayurvedic and Chinese herbal medicine. Two trials by the maker of a standardized rhizome extract reported weight and waist loss in adults with obesity, one with added piperine. Separate small trials of the topical essential oil looked at unwanted hair and underarm darkening. No health agency has reviewed it.

Every graded outcome on this page

5 rows · line = participants

Grade CUnderarm hyperpigmentationSkin darkeningn 153
Grade CPain and redness after laser hair removalPost-laser skinn 153
Grade CBody weight, BMI and waist circumference in obesityWeight lossn 96
Grade CUnwanted underarm hair growthUnwanted hairn 65
Grade DBody weight, BMI, waist circumference and lipids in obesityWeight lossn 30

Key facts

Weight trials: Both oral trials tested one standardized rhizome extract and were run by its maker, Sami-Sabinsa^1,2
Largest oral trial: 96 adults with obesity, 500 mg extract plus 5 mg piperine twice daily vs placebo for 90 days, with diet and exercise; weight, BMI, waist and hip fell more¹
Extract standard: Standardized to 6-8% stilbenes (scirpusin A, scirpusin B and piceatannol)¹
Topical oil trials: Three randomized trials of the essential oil on the skin come from a single Egyptian author^3,4,5
Agency safety reviews: No ODS, NCCIH, LactMed, LiverTox, Health Canada or EMA monograph covers Cyperus rotundus⁶

What it is

Purple nutsedge (Cyperus rotundus) is a weedy sedge whose rhizome is used in traditional medicine and sold as a standardized extract.

How it works

Proposed

The tubers and rhizomes contain essential oils, phenolic acids and flavonoids, and lab studies describe anti-androgenic, anti-inflammatory and anti-obesity activity. The weight-loss extract is standardized to stilbenes; it reduced fat-cell formation in cultured cells and weight gain in mice fed a high-fat diet. These are lab and animal findings, not human data.^7,2

Forms, side by side

3 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.

Purple nutsedge (Cyperus rotundus) forms compared

3 forms

Purple nutsedge (Cyperus rotundus) forms compared: 3 forms by 3 attributes. Empty cells are labelled No data yet, or Not graded in the evidence row.
3 forms	Standardized rhizome extract capsules	Essential oil applied to the skin	Dried rhizome or tuber powder
Absorption in people	No head-to-head human data¹	Not applicable (applied to the skin)³	No head-to-head human data⁷
GI tolerance	No adverse events were reported in the 96-person or 30-person 90-day trials.^1,2	No side effects were detected in the 2014 hair-removal pilot.³	Not studied on its own in controlled human trials.⁷
Studied for	Weight and lipids in adults with obesity	Unwanted underarm hair, underarm darkening, pain after laser hair removal	Traditional use only; no controlled human trials of the powder alone

Standardized rhizome extract capsules
Absorption in people
No head-to-head human data¹
GI tolerance
No adverse events were reported in the 96-person or 30-person 90-day trials.^1,2
Studied for
Weight and lipids in adults with obesity
Essential oil applied to the skin
Absorption in people
Not applicable (applied to the skin)³
GI tolerance
No side effects were detected in the 2014 hair-removal pilot.³
Studied for
Unwanted underarm hair, underarm darkening, pain after laser hair removal
Dried rhizome or tuber powder
Absorption in people
No head-to-head human data⁷
GI tolerance
Not studied on its own in controlled human trials.⁷
Studied for
Traditional use only; no controlled human trials of the powder alone

What the human research says

Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.

Trial map

5 graded outcomes, largest study first

All 5 graded outcomes found an improvement. The largest, a 2022 randomized trial of 153 people on underarm hyperpigmentation, found an improvement.

By sizeTable

1Underarm hyperpigmentation

Improved · Grade C · RCT, 153 people, 2022

Adults with axillary hyperpigmentation (Egypt)

Dose, result and source

Every graded outcome on this page, largest study first
Outcome	Found	People	Study	Who was studied
Underarm hyperpigmentation	Improved	153	Grade C · RCT, 2022	Adults with axillary hyperpigmentation (Egypt)
Pain and redness after laser hair removal	Improved	153	Grade C · RCT, 2022	Adults having laser hair removal (Egypt)
Body weight, BMI and waist circumference in obesity	Improved	96	Grade C · RCT, 2025	Adults with obesity following a prescribed diet and exercise plan
Unwanted underarm hair growth	Improved	65	Grade C · Pilot RCT, 2014	Adults with unwanted axillary hair (Egypt)
Body weight, BMI, waist circumference and lipids in obesity	Improved	30	Grade D · Pilot RCT, 2022	Adults with obesity (BMI 30-40)

Every graded row

5 rows

Form tested

Showing 5 of 5 outcomes. Human trials only.

Grade CUnderarm hyperpigmentationSkin darkeningSimilar to hydroquinoneRCT
n 153 · 2022

Improved Double-blind trial vs hydroquinone and a placebo cold cream. The oil and hydroquinone did not differ on lightening, while the oil did better on inflammation and hair regrowth. The abstract also states the oil had better lightening than hydroquinone, which conflicts with that result.

Design: RCT, n = 153, 2022
Population: Adults with axillary hyperpigmentation (Egypt)
Form: Topical Cyperus rotundus essential oil
Dose: Not stated in the abstract (applied to the skin)
Duration: Not stated in the abstract
Source: Reference 4 · PubMed 34618367 (opens PubMed)

Grade CPain and redness after laser hair removalPost-laser skinLess painRCT
n 153 · 2022

Improved Randomized vs hydrocortisone and saline. Redness control did not differ between the oil and hydrocortisone; pain relief favoured the oil.

Design: RCT, n = 153, 2022
Population: Adults having laser hair removal (Egypt)
Form: Topical Cyperus rotundus essential oil
Dose: Not stated in the abstract (applied to the skin)
Duration: Not stated in the abstract
Source: Reference 5 · PubMed 34132024 (opens PubMed)

Grade CBody weight, BMI and waist circumference in obesityWeight lossMore weight and waist lossRCT
n 96 · 2025

Improved Double-blind vs placebo. Body weight, BMI, waist and hip circumference fell more with the extract, and blood lipids and apolipoprotein B-100 improved. No adverse events were reported and lab safety values stayed in normal ranges.

Design: RCT, n = 96, 2025
Population: Adults with obesity following a prescribed diet and exercise plan
Form: Standardized Cyperus rotundus rhizome extract (6-8% stilbenes) with piperine
Dose: 500 mg extract + 5 mg piperine twice daily
Duration: 90 days
Source: Reference 1 · PubMed 41305713 (opens PubMed)

Grade CUnwanted underarm hair growthUnwanted hairSimilar to laserPilot RCT
n 65 · 2014

Improved Open-label pilot comparing the oil with saline and Alexandrite laser. Overall hair reduction did not differ between the oil and the laser, and the oil did better on white hair. No side effects were detected. 60 of 65 finished.

Design: Pilot RCT, n = 65, 2014
Population: Adults with unwanted axillary hair (Egypt)
Form: Topical Cyperus rotundus essential oil
Dose: Not stated in the abstract (applied to the skin)
Duration: Not stated in the abstract
Source: Reference 3 · PubMed 24408514 (opens PubMed)

Grade DBody weight, BMI, waist circumference and lipids in obesityWeight lossWeight and waist downPilot RCT
n 30 · 2022

Improved Double-blind pilot vs placebo. Body weight fell, and waist circumference, BMI and the blood lipid profile improved significantly. The extract was well tolerated with no adverse effects reported.

Design: Pilot RCT, n = 30, 2022
Population: Adults with obesity (BMI 30-40)
Form: Standardized Cyperus rotundus rhizome extract (piceatannol, scirpusin A and B)
Dose: 525 mg twice daily before meals (from the full text)
Duration: 90 days
Source: Reference 2 · PubMed 35177914 (opens PubMed)

Other human studies (not graded)

1 note

Human data that cannot be graded as an outcome row.

Genital skin darkening (topical oil): A 2022 study sharing the lead author of the other topical trials assigned 308 people to the essential oil, arbutin or a cold cream. Lightening was greater with the oil and with arbutin than with the cold cream, and no adverse effects were reported with the oil. The abstract does not say participants were randomized, so it is not graded.⁸

What the numbers add up to

Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.

One maker, one author

Every oral trial comes from the company that sells the standardized extract, and every topical study shares one lead author, including a fourth, ungraded 2022 study. No independent group has repeated either line of research.^1,2,3,4,5,8

Studied doses

Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.

Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Doses studied in human trials

Doses studied in human trials ranged from 500 mg of extract twice a day (with 5 mg piperine) to 525 mg twice a day, each for 90 days. These are research doses, not recommendations.^1,2

Interactions and safety

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

What Purple nutsedge meets

0 cited rows 1 tested together

Medicines 0

No medicine rows in our sources.

Purple nutsedge0 medicines · 1 supplement

Supplements and foods 1

Tested together in a graded trial

Also cited: 1 tested together

Black PepperBlack Pepper page
- Tested together
  Body weight, BMI and waist circumference in obesity. Graded on the Purple nutsedge page; tested together is not a claim that they work better together.

Interactions

0 agents

None found in our sources.

Check with what you take

Kept on this device only

Add what you take. We list every interaction our evidence profiles cite between Purple nutsedge and your picks, and between your picks.

Add a supplement or medicine

Most cited:

Add a supplement or medicine you take to check it against Purple nutsedge.

Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.

Who should be careful

4 groups

Pregnancy and breastfeeding: No ODS, NCCIH, LactMed, LiverTox, Health Canada or EMA source covers Cyperus rotundus. NCCIH notes that many dietary supplements have not been tested in pregnant or nursing women.⁶
People on medicines: No drug-interaction data were found in ODS, NCCIH, LactMed, LiverTox, Health Canada or EMA sources. NCCIH advises telling your health care providers about any supplement, since supplements can interact with medicines.⁶
Before surgery: NCCIH advises telling the surgical team about every supplement in advance, since some can affect bleeding or anesthesia.⁶
Weight-loss products: NCCIH warns that some products marketed as supplements for weight loss have contained prescription drugs or other ingredients not listed on the label.⁶

Frequently asked questions

Short answers to common questions; the numbers link to the sources below.

Common questions

5 answers

Does Cyperus rotundus help with weight loss?

Two trials by the extract's maker reported more weight and waist loss than placebo over 90 days, one in 30 people and one in 96 people who also took piperine. Independent trials are lacking.^1,2

What is purple nutsedge used for traditionally?

Its tubers and rhizomes have been used in traditional medicine for diarrhea, stomach and bowel complaints, fever and inflammation. Those uses come from tradition and lab work, not from controlled human trials.⁷

Does Cyperus rotundus oil remove hair?

One open-label pilot by a single author found underarm hair reduction similar to Alexandrite laser. It has not been independently repeated.³

Is it safe?

The 90-day trials reported no adverse events, but no health agency has reviewed Cyperus rotundus, and safety in pregnancy, breastfeeding or with medicines is unknown.^1,2,6

What dose was studied?

500 to 525 mg of the standardized rhizome extract twice a day for 90 days.^1,2

Sources

8 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.

Sources cited on this page

8 sources

1Efficacy and safety of Cyperus rotundus extract on weight management in obese individuals: A randomized, double-blind, placebo-controlled study.RCT Medicine (Baltimore), 2025 · PMID 41305713
2The Anti-Obesity Potential of Cyperus rotundus Extract Containing Piceatannol, Scirpusin A and Scirpusin B from Rhizomes: Preclinical and Clinical Evaluations.Pilot RCT Diabetes Metab Syndr Obes, 2022 · PMID 35177914
3Topical Cyperus rotundus oil: a new therapeutic modality with comparable efficacy to Alexandrite laser photo-epilation.Pilot RCT Aesthet Surg J, 2014 · PMID 24408514
4Topical Cyperus rotundus essential oil for treatment of axillary hyperpigmentation: a randomized, double-blind, active- and placebo-controlled study.RCT Clin Exp Dermatol, 2022 · PMID 34618367
5The effectiveness of Cyperus rotundus essential oil in reducing the side effects of laser hair removal.RCT J Cosmet Dermatol, 2022 · PMID 34132024
6Using Dietary Supplements WiselyFact sheet National Center for Complementary and Integrative Health (NCCIH), 2019 · nccih.nih.gov
7Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities.Review J Ethnopharmacol, 2015 · PMID 26297840
8Genital whitening with topical Cyperus rotundus oil enhances sexuality and quality of life.Observational J Cosmet Dermatol, 2022 · PMID 35290702

What changed

Every dated change to this page: what changed, who made it and why.

Change log

2 entries

Dated changes to this page
Date	Change	Who and why
Oct 21, 2026research notes, insights	Searched PubMed for 2023–2026 trials: nothing newer than the 2025 weight trial. Added an ungraded 2022 topical study (PMID 35290702, checked with NCBI esummary and abstract read) to research notes and the one-author insight. Interactions re-checked: no ODS, NCCIH, LactMed or LiverTox entry covers Cyperus rotundus, so the list stays empty.	Writer: Kymata Health EditorialTrigger: A–Z page audit
Oct 14, 2026all	Initial editorial evidence review	Writer: Kymata Health EditorialTrigger: new page

Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.

Purple nutsedge (Cyperus rotundus)

Medicines 0

Supplements and foods 1

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