Rosemary leaf oil extract
Also known as: Rosemary leaf oil extract, rosemary essential oil, Salvia rosmarinus, Rosmarinus officinalis
Overview
Rosemary leaf oil extract is derived from the leaves of the rosemary plant, Rosmarinus officinalis, through processes like steam distillation or solvent extraction. It contains bioactive compounds such as rosmarinic acid, carnosic acid, and cineole. Traditionally used for culinary flavoring, it is also applied in supplements for its potential in cognitive enhancement, antioxidant support, anti-inflammatory effects, hair growth promotion, and possible anticancer properties. The extract is rich in antioxidants and exhibits anti-inflammatory, antimicrobial, and neuroprotective properties. While several in vitro, animal, and human studies exist, including some clinical trials, large-scale, high-quality randomized controlled trials (RCTs) are still limited, indicating a moderate level of research maturity.
Benefits
Rosemary leaf oil extract offers several evidence-based benefits. It exhibits significant antioxidant and neuroprotective properties, primarily through anticholinesterase inhibitory activity and free radical scavenging, which may protect brain function and reduce oxidative stress. Its anti-inflammatory effects stem from compounds like rosmarinic acid, which can inhibit pro-inflammatory cytokines such as IL-6 and modulate signaling pathways like STAT3. This contributes to its potential in reducing inflammation and has shown promise in preclinical models for anticancer effects by reducing cancer cell viability and modulating pathways like hypoxia-inducible factor 1α. Some clinical evidence suggests rosemary oil may promote hair growth and slow hair loss, though more robust trials are needed to confirm efficacy. A clinical study observed borderline significant decreases in dehydroepiandrosterone and androstenedione, suggesting potential modulation of sex steroid hormones, though no broad hormonal disruptions were noted. Cognitive and mental health benefits may be more relevant to older adults or those with neurodegenerative conditions, while anticancer effects are currently limited to preclinical models. Quantitative effect sizes are limited, but some hormonal changes showed statistical significance (e.g., -13.2% dehydroepiandrosterone, p=0.02). The time course for benefits is not well-defined, but antioxidant and anti-inflammatory effects may be observed with regular use.
How it works
Rosemary leaf oil extract exerts its effects through several primary biological pathways. Its antioxidant activity involves scavenging free radicals, thereby reducing oxidative stress. Anti-inflammatory effects are achieved through the inhibition of pro-inflammatory cytokines and signaling pathways, such as IL-6 and STAT3. For its potential anticancer effects, it is believed to suppress the Warburg effect (altered cancer cell metabolism) and induce endoplasmic reticulum stress selectively in cancer cells. The extract interacts with the nervous system, providing neuroprotection, and the endocrine system, potentially modulating sex steroids. It also influences cellular metabolism, particularly in cancer cells. Known molecular targets include cholinesterase enzymes, hypoxia-inducible factor 1α, inflammatory cytokines, and androgen receptors. While specific bioavailability data are limited, the lipophilic nature of essential oils suggests good absorption through oral or topical routes.
Side effects
Rosemary leaf oil extract is generally regarded as safe with minimal side effects at typical doses. Common side effects are rare, but mild gastrointestinal discomfort or skin irritation are possible, especially with topical use. Uncommon side effects are not well-documented. Rare side effects include potential genotoxicity observed at very high doses in animal studies, though this has not been confirmed in humans. Individuals with a known allergy to rosemary or related plants should avoid its use. Caution is advised regarding drug interactions, as rosemary may interact with anticoagulants (blood thinners) and antihypertensive drugs (blood pressure medications). There is limited data on its use during pregnancy and breastfeeding, so caution is recommended for these special populations. Overall, while generally safe, awareness of potential interactions and individual sensitivities is important.
Dosage
The minimum effective dose for rosemary leaf oil extract is not definitively established, but some studies have used 100 mg of rosemary extract in supplements. Optimal dosage ranges vary by formulation, and essential oil doses in clinical studies are typically low due to their potency. The maximum safe dose for humans is not precisely defined, though very high doses (e.g., 2000 mg/kg in animals) have shown genotoxicity. Regular daily intake may be required for sustained effects. Rosemary leaf oil extract is commonly available in various forms, including oral capsules, topical oils, and as a food additive. The absorption of its lipophilic compounds may be enhanced when consumed with fatty meals. No specific cofactors are identified as required for its efficacy.
FAQs
Is rosemary leaf oil extract safe?
Yes, rosemary leaf oil extract is generally considered safe for most people when used at recommended doses, with minimal side effects reported.
Can rosemary oil promote hair growth?
Preliminary evidence suggests rosemary oil may have potential benefits for promoting hair growth and reducing hair loss, but more rigorous clinical trials are needed to confirm these effects.
How long until effects are seen?
The time frame for observing effects can vary depending on the intended use and individual response, often taking weeks to months. Specific data on this is limited.
Are there any drug interactions?
Yes, rosemary leaf oil extract may interact with certain medications, including blood thinners and blood pressure medications. It is advisable to consult a healthcare provider before use if you are on medication.
Is it effective for cancer?
While promising preclinical data exist showing potential anticancer properties, there is currently no conclusive human clinical evidence to support its effectiveness as a cancer treatment.
Research Sources
- https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2024.1337785/full – This systematic review explored the antioxidant, anti-inflammatory, and anticancer mechanisms of rosemary essential oil, emphasizing rosmarinic acid's role in inhibiting cancer cell metabolism and inflammation. It highlighted potential for neuroprotection and selective cancer cell targeting but underscored the need for more clinical trials to validate these findings.
- https://www.cir-safety.org/sites/default/files/rosmar062014FR.pdf – This safety assessment report evaluated the genotoxicity and hormonal effects of rosemary leaf oil and extract. It found no mutagenicity in vitro, minor hormonal changes in humans at a 100 mg dose, and some genotoxicity at very high doses in animal studies, concluding that rosemary is safe at typical exposure levels.
- https://www.mdpi.com/2304-8158/10/12/3143 – This study demonstrated the safety and beneficial biological properties of rosemary essential oil and extract when used as a drink ingredient. It supported its use in food and supplements, indicating that it does not cause significant adverse effects at typical consumption levels.
- https://www.medicalnewstoday.com/articles/319444 – This article discusses the potential benefits of rosemary oil for hair growth, citing some clinical evidence that suggests it may promote hair growth and slow hair loss. It also notes that more robust trials are needed to confirm its efficacy in this area.
- https://www.medicalnewstoday.com/articles/266370 – This article provides a general overview of rosemary oil, including its traditional uses and some of its purported health benefits. It touches upon its safety profile and common applications, aligning with the general understanding of rosemary's safety at typical doses.
