Rosemary Supplements: History, Memory, Stress and Modern Research

What is rosemary?

Rosemary is the familiar cooking herb Salvia rosmarinus, also called Rosmarinus officinalis. That familiar name can hide several very different products: culinary leaf, medicinal tea, ground leaf in a capsule, a concentrated extract, essential oil and a scent released into a room.

Research now covers memory, mood, sleep, metabolic measurements and a particular skin formula. The sections below group those findings by preparation and purpose.

How was rosemary used historically?

Rosemary's history includes household medicine, religious beliefs and symbols of remembrance. The Metropolitan Museum's account of European herbals^[1] describes preparations applied to wounds, toothache and itching. Later medieval writings added claims of spiritual protection. By the early modern period, rosemary was also a token at weddings and funerals, associated with memory and remembrance. These accounts document what people believed and practiced but do not establish that the remedies worked.

Rosemary-leaf tea and medicinal baths remain recognized traditional uses in European herbal guidance; their purposes and directions are discussed below.

What people take rosemary for

Review pending means the source assessment is incomplete. Study amounts describe the preparations tested.

How do the preparations compare?

Culinary leaf is used in food. Ground-leaf capsules contain the whole powdered leaf, while tea extracts some of its constituents into water.

Concentrated extracts vary with how they are made. Their weight cannot be converted into the amount of leaf used in a trial without that information. Essential oil is a concentrated preparation used in scent studies.

Check the plant part, amount per serving, recommended number of servings and any declared extraction ratio. A 10:1 ratio means 10 parts starting plant material were used to make 1 part extract by weight. It describes concentration during manufacture; the studied extract’s composition still matters when comparing research with a product.

Swallowed leaf and extracts: memory, mood and other outcomes

Dried leaf and memory

In a 2012 crossover trial^[2] of 28 older adults, each person tried placebo and several doses of dried rosemary leaf on different visits, separated by a week. Memory speed was better after 750 mg and worse after 6,000 mg. Tests took place one to six hours after dosing. The result suggests that more is not necessarily better, but it does not show that daily use preserves memory over months or years.

A 2018 trial in 68 university students^[3] used 500 mg twice daily for a month and reported improved self-rated memory, anxiety and depression scores. The same trial found better self-reported sleep quality, with no reported improvement in sleep latency or sleep duration: how quickly students fell asleep and how long they slept. These were self-reported outcomes. The age groups and regimens also differ, so the two trials cannot establish an optimal rosemary dose.

Attention and energy: the capsule result was not consistently positive

A 2013 study in 40 young adults with low feelings of energy^[4] compared capsule preparations containing 1.7 g rosemary, black pepper or rice-flour placebo across separate visits. Each participant received two of the three preparations. The rosemary preparation combined Rosmarinus officinalis and Rosmarinus eriocalyx. Participants wore nose clips to block smell. Rosemary did not consistently improve sustained attention, motivation, energy or fatigue. Small changes at isolated testing times did not hold up in the main adjusted attention analysis.

Cognition and everyday activities in COPD

A trial in 77 adults aged 40–80 with chronic obstructive pulmonary disease^[5] compared 500 mg rosemary-extract capsules twice daily with corn-powder placebo for two months. For daily activities, the authors describe the initial comparison as showing no clear difference, but print a statistical value that conflicts with that description.

The researchers then accounted for obstructive sleep apnoea, a condition in which breathing repeatedly stops during sleep. In that analysis, the rosemary group improved more on a thinking-and-memory screening test and an independent-living questionnaire. A separate measure of activities affected by lung disease did not improve. The favorable findings therefore depend on the adjusted analysis; how large or useful those differences would be in everyday life remains uncertain.

Mood and daily stress

A 2022 placebo-controlled trial^[6] added rosemary capsules to usual treatment for people with major depression for eight weeks and reported better depression and anxiety scores. Rosemary was added to supervised treatment. If you plan to add rosemary capsules while taking medicine for a mood condition, bring the actual label to your prescriber.

A separate 2025 trial^[7] studied daily stress in healthy Japanese adults. Forty were randomized and 38 analyzed in a crossover comparing placebo with 200 mg extract daily, supplying 5 mg rosmarinic acid and 8 mg diterpenes, constituents used to characterize the particular extract tested. Each treatment lasted four weeks.

Participants reported less anxiety when asked how they generally felt, but their ratings of anxiety at that moment did not differ significantly after four weeks. During a same-day mental-work test, ratings of anxiety at that moment favored the extract. Levels of cortisol, a hormone involved in the stress response, and separate ratings of perceived stress did not differ.

The manufacturer funded the study and employed all authors.

Blood sugar, cholesterol and fatty liver

Earlier small reports in 2014^[8] and 2018^[9] observed improved blood tests after rosemary powder. Participants with diabetes continued their medicines, and everyone received rosemary; there was no untreated or placebo group to isolate its contribution. The 2014 study included 45 people with type-2 diabetes and 15 without, using 3 g daily for four weeks. The 2018 report followed 40 people with diabetes and 10 without for eight weeks at the same daily powder amount.

A 2022 placebo-controlled trial^[10] assigned 110 people with nonalcoholic fatty liver disease to 4 g rosemary leaf powder or starch placebo for eight weeks. Both groups received weight-loss diet and physical-activity advice. Liver enzymes, weight, and several glucose and cholesterol measurements improved in both groups, but the changes did not differ significantly between groups except for one calculated index estimating the function of the insulin-producing cells in the pancreas. The abstract does not give the direction of that difference, and this isolated result does not establish a clinical improvement. Rosemary did not demonstrate an added benefit for the other reported measures beyond the lifestyle programme.

A particular oral formula and facial skin quality

A 2025 placebo-controlled study^[11] enrolled 104 women aged 40–65 to test a proprietary rosemary-containing formula for 12 weeks. Investigator ratings favored the formula for dullness, texture, redness and pore size, but not uneven pigmentation. One woman stopped because of possibly related gastrointestinal upset. The authors reported company employment or consulting relationships.

The tested formula also contained biotin and zinc, so its result cannot identify the contribution of rosemary alone.

Rosemary scent and memory tasks

In a 2003 room-scent study^[12], 144 healthy adults completed memory tasks in rooms scented with rosemary, lavender or no added scent. Some memory-quality measures improved with rosemary, while speed slowed.

Traditional leaf tea and medicinal baths

The EMA rosemary-leaf guidance^[13] recognizes tea for indigestion and mild digestive cramps, and bath preparations for minor muscle, joint and peripheral-circulation complaints. These are traditional-use indications, based on longstanding practice with insufficient clinical-trial evidence.

For indigestion, its directions specify 1–2 g leaf per cup, two or three times a day. Symptoms persisting more than two weeks need medical review.

The resulting 2–6 g daily tea-leaf range is divided among cups.

For medicinal baths, the leaf monograph^[14] advises against application to broken or irritated skin. It calls for caution with full hot baths in high blood pressure and medical advice for people with heart or kidney insufficiency.

What should you check before taking it?

Does rosemary raise estrogen?

The human trials summarized here did not establish an estrogen effect. A rosemary product should not be chosen as a hormone treatment on that basis.

The bottom line

Rosemary has a long history as a food, remedy and symbol of remembrance. Modern studies test specific leaf preparations, extracts and scent exposures, and their results are mixed. Small memory, mood and stress trials report some favorable outcomes; an attention study was not consistently positive, and the fatty-liver trial found no added benefit for most metabolic measurements alongside lifestyle advice.

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