{"ok":true,"entry":{"slug":"oregano-oil","kind":"supplement","name":"oregano oil","aliases":["Origanum vulgare","carvacrol"],"brands_sg":["NOW Foods","Micro Ingredients","Swanson Vitamins","Garden of Life","North American Herb & Spice"],"class":"botanical oil","tags":["immune","gut"],"use_for":"lab antimicrobial activity — human trials still lacking","use_after":null,"use_duration":null,"take_with":null,"pros":["thymol and carvacrol carry the antimicrobial activity","in vitro: s. aureus, salmonella, shigella, e. coli","mechanisms mapped: membrane damage, biofilm block"],"cons":["human trials on carvacrol are still lacking (2018)","antimicrobial data are in-vitro and animal only","no standardised human dose has been established"],"dose_note":"no human dose can be reported for oregano oil, because a 2018 comprehensive review of carvacrol — the constituent the products are sold on — states that human trials on it are still lacking and that this largely impedes any conclusions of clinical relevance; the 2021 origanum vulgare review and the 2022 carvacrol review both describe activity confirmed in in-vitro and in-vivo studies and list the organisms and mechanisms involved, but neither supplies a studied human intake, and the 2021 review works across o. vulgare and its subspecies rather than a single standardised product, so a figure on one label is not comparable to another; hsa's october 2025 annex a (118 rows) and annex b (4 rows) do not list origanum, oregano or carvacrol, and hsa's tables 4 and 5 cap vitamins and minerals only, so no singapore daily limit exists for it","dosage":{"ul":null,"unit":null,"fda_dv":null,"rda_ai":null,"ul_status":"none_established","population":"general adult","hsa_max_daily":null},"ul_status":"none_established","sg_class":null,"cautions":["a 2018 review says lacking human trials largely impede any conclusions of clinical relevance","the reviewed activity is from o. vulgare and its subspecies, tested in vitro and in animals","not listed in hsa's prohibited or restricted annexes — that is not a safety finding","no singapore daily limit — hsa tables 4–5 cover vitamins and minerals only"],"clashes":[],"sources":[{"id":"epmc_origanum_2021","url":"https://europepmc.org/article/MED/34567161","label":"Soltani et al., A Review of the Phytochemistry and Antimicrobial Properties of Origanum vulgare L. and Subspecies (Iran J Pharm Res 2021, PMID 34567161) — constituents","quote":"The constituents of the O. vulgare essential oil (EO) include high percentages of thymol and carvacrol with excellent antimicrobial activity alone or in combination with other antibiotics.","accessed":"2026-08-27"},{"id":"epmc_origanum_2021_mech","url":"https://europepmc.org/article/MED/34567161","label":"Soltani et al. 2021 (PMID 34567161) — mechanisms and study types","quote":"The most important antibacterial mechanisms of O. vulgare are enzyme inhibition, efflux pump inhibition, ATP depletion, biofilm formation inhibition and cytoplasmic membrane damage … confirmed in different in-vitro and in-vivo studies.","accessed":"2026-08-27"},{"id":"epmc_carvacrol_2018","url":"https://europepmc.org/article/MED/29744941","label":"Sharifi-Rad et al., Carvacrol and human health: A comprehensive review (Phytother Res 2018, PMID 29744941)","quote":"Carvacrol (CV) is a phenolic monoterpenoid found in essential oils of oregano (Origanum vulgare) … to date, human trials on CV are still lacking, and this largely impedes any conclusions of clinical relevance.","accessed":"2026-08-27"},{"id":"epmc_carvacrol_2022","url":"https://europepmc.org/article/MED/36348778","label":"Imran et al., Therapeutic application of carvacrol: A comprehensive review (Food Sci Nutr 2022, PMID 36348778)","quote":"Carvacrol also has been found to exert antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Coagulase-negative staphylococcus, Salmonella spp., Enterococcus sp. Shigella, and Escherichia coli.","accessed":"2026-08-27"},{"id":"hsa_prohibited","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (October 2025), Annex A (118 rows) and Annex B (4 rows) — Origanum vulgare / oregano / carvacrol NOT LISTED in either (Annex A neighbours: 67. Melaleuca, 77. Papaver spp.)","quote":"The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list.","accessed":"2026-08-27"},{"id":"hsa_hs_guidelines","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines GL-CHPB-3-001 Rev. No. 020 (January 2026), clause 4.8 with Tables 4–5 (vitamins and minerals only — no botanical or bee-product rows)","quote":"4.8 HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5.","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/oregano-oil","label":"iHerb Singapore — Oregano Oil category page, default listing order","quote":"1 - 48 of 64 results … NOW Foods, Oregano Oil … Micro Ingredients, Oil of Oregano … Swanson Vitamins, Oregano Oil … Garden of Life, Organics, Oil of Oregano … North American Herb & Spice, Oreganol™, Oil of Wild Oregano","accessed":"2026-08-27"}],"brand_certs":[{"brand":"Garden of Life","example":null,"programme":"NSF Certified for Sport","matching_products":0,"brand_total_certified":23}],"updated_at":"2026-08-30T17:59:39.960259+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}