Spearmint
Summary
Spearmint (Mentha spicata) has two lines of evidence. Twice-daily spearmint tea lowered free testosterone in women with hirsutism in two small studies, but did not reduce clinician-rated hair growth over 30 days. A rosmarinic-acid-rich extract at 900 mg/day improved working memory or attention in two 90-day trials of 90 and 142 adults.
Key facts
- A mint species (Mentha spicata), used as a tea or as a dried aqueous leaf extract standardised to rosmarinic acid[3][5]
- Free and total testosterone fell over 30 days of twice-daily tea in 42 women with PCOS[1]
- Clinician-rated hirsutism (Ferriman-Gallwey score) did not change significantly in 30 days (p=0.12)[1]
- 900 mg/day of extract improved working memory by 15% in 90 adults with age-associated memory impairment[3]
- 600–900 mg/day for 90 days did not change FSH, LH or TSH or safety blood tests[5]
- 5 graded human outcomes on this page
- October 13, 2026
How it works
ProposedSpearmint tea lowered free testosterone and raised LH and FSH in women with hirsutism, suggesting an anti-androgen action; the responsible compounds are not established. The memory extract is rich in rosmarinic acid and other polyphenols; how it affects cognition is proposed, not shown.[1][2][3]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Attention | Grade C | Mixed | RCT · n = 142 · 2019 | 1 row |
| Memory | Grade C | Improved | RCT · n = 90 · 2018 | 1 row |
| Joint pain | Grade D | Mixed | RCT · n = 46 · 2014 | 1 row |
| Hirsutism | Grade D | Mixed | RCT · n = 42 · 2010 | 2 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Cognitive performance in healthy active adults | Mixed | Grade C | RCT · n = 142 · 2019 Healthy, recreationally active men and women Form: Proprietary spearmint extract · Dose: 900 mg/day · Duration: 90 days Sustained attention was better than placebo at days 30 and 90, and complex attention at day 7; other cognitive domains, mood, sleep and quality of life did not differ. | 30802720 (opens PubMed)Source [4] |
| Working memory, sleep and mood in age-associated memory impairment | Improved | Grade C | RCT · n = 90 · 2018 Adults with age-associated memory impairment (mean age 59) Form: Dried aqueous spearmint extract high in rosmarinic acid · Dose: 600 or 900 mg/day · Duration: 90 days At 900 mg/day, quality of working memory rose 15% and spatial working memory accuracy 9% versus placebo, and falling asleep improved; 600 mg/day was less effective. | 29314866 (opens PubMed)Source [3] |
| Knee osteoarthritis pain, stiffness and function | Mixed | Grade D | RCT · n = 46 · 2014 Adults with knee osteoarthritis Form: High-rosmarinic acid spearmint tea vs commercial spearmint tea · Dose: One cup twice daily · Duration: 16 weeks Pain fell within the high-rosmarinic acid group only, and stiffness and disability improved in both groups; there were no significant differences between groups. | 25058311 (opens PubMed)Source [7] |
| Androgens and hirsutism in PCOS | Mixed | Grade D | RCT · n = 42 · 2010 Women with polycystic ovary syndrome and hirsutism Form: Spearmint herbal tea · Dose: One cup twice daily · Duration: 30 days Free and total testosterone fell and LH and FSH rose versus placebo tea; self-rated hirsutism improved, but clinician-rated Ferriman-Gallwey scores did not differ (p=0.12). | 19585478 (opens PubMed)Source [1] |
| Androgen levels in hirsutism | Mixed | Grade D | Open-label trial · n = 21 · 2007 Women with hirsutism (12 with PCOS, 9 idiopathic; Turkey) Form: Spearmint tea · Dose: One cup twice daily · Duration: 5 days (follicular phase) Free testosterone fell and LH, FSH and estradiol rose; total testosterone and DHEA-S did not fall. | 17310494 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Spearmint tea (dried leaf) | Varies[1][2][7] | No human absorption data.[1] | No adverse effects were described in the abstracts of the tea trials.[1][2] | Hirsutism and knee osteoarthritis trials |
| Spearmint extract standardised to rosmarinic acid | Varies[3][4][6] | No human absorption data in the cited trials.[3] | 600 and 900 mg/day for 90 days did not change reproductive or thyroid hormones or other safety measures, and adverse events did not differ from placebo.[5] | Memory and attention trials (600–900 mg/day) |
Studied doses
Doses studied in human trials ranged from 600 to 900 mg/day of a rosmarinic-acid-rich spearmint extract for 17–90 days. Tea trials used one cup twice daily for 5 days to 16 weeks.[1][2][3][4][6][7]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Hormone therapies
- Spearmint tea lowered testosterone and raised LH and FSH in women; no studies have tested it alongside hormonal contraceptives, fertility drugs, testosterone or anti-androgen medicines.[1][2]
- Men concerned about testosterone or fertility
- Not tested in men. In male rats, spearmint tea given as drinking water lowered testosterone and caused dose-related damage to sperm-producing tissue; the Turkish hirsutism studies began after local reports of reduced libido in men drinking mint tea.[8][2]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
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Frequently asked questions
Does spearmint tea help with PCOS hair growth?
It lowered testosterone in women with PCOS within 30 days, but clinician-rated hair growth did not change significantly in that short trial. Women did rate their own hirsutism as improved.[1]
Does spearmint improve memory?
A specific extract at 900 mg/day improved working memory in 90 older adults and sustained attention in 142 younger adults over 90 days.[3][4]
Can men drink spearmint tea?
No human trial has tested its hormonal effects in men. In male rats, spearmint tea lowered testosterone and damaged sperm-producing tissue at higher doses, so men concerned about testosterone or fertility have reason for caution with large daily amounts.[8][2]
Is spearmint extract safe?
In a 90-day trial, 600–900 mg/day did not change reproductive or thyroid hormones and caused no more adverse events than placebo.[5]
Sources
- [1]Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. A randomized controlled trial.. Phytother Res, 2010. RCT
- [2]Effect of spearmint (Mentha spicata Labiatae) teas on androgen levels in women with hirsutism.. Phytother Res, 2007. open-label
- [3]Spearmint Extract Improves Working Memory in Men and Women with Age-Associated Memory Impairment.. J Altern Complement Med, 2018. RCT
- [4]The attention-enhancing effects of spearmint extract supplementation in healthy men and women: a randomized, double-blind, placebo-controlled, parallel trial.. Nutr Res, 2019. RCT
- [5]Safety and tolerability of a dried aqueous spearmint extract.. Regul Toxicol Pharmacol, 2017. RCT
- [6]Effect of Spearmint Extract Containing Rosmarinic Acid on Physical and Executive Functioning After a Tactical Operation.. J Spec Oper Med, 2018. RCT
- [7]High-rosmarinic acid spearmint tea in the management of knee osteoarthritis symptoms.. J Med Food, 2014. RCT
- [8]Effects of peppermint teas on plasma testosterone, follicle-stimulating hormone, and luteinizing hormone levels and testicular tissue in rats.. Urology, 2004. animal-study
What changed
- Independent adversarial review: added the missing anti-androgen caution for men (rat data: lower testosterone and dose-related testicular damage) and rewrote the men FAQ, which previously said only that effects were unknown. Added maker-funding note to the memory trial. All PMIDs re-verified.
- Adversarial second pass: every PMID re-checked against NCBI esummary (title, year, no retraction, erratum or expression-of-concern flags) and every number in each evidence row re-read against its PubMed abstract (PMC full text where the abstract lacked dose or duration). Countries and funding notes kept only where the abstract or full text states them; interactions listed only where a source supports them, otherwise stated as unstudied.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.