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Oregano oil

Supplement botanical oil immunegut
Aka: Origanum vulgare, carvacrol
Brands seen in Singapore: NOW Foods, Micro Ingredients, Swanson Vitamins, Garden of Life, North American Herb & Spice
Third-party tested: Garden of Life certifies other products with NSF Certified for Sport, but nothing for oregano oil.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Lab antimicrobial activity — human trials still lacking
Pros & cons
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
Sources
  1. 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 · read 2026-08-27
    what it says
    “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.”
  2. Soltani et al. 2021 (PMID 34567161) — mechanisms and study types · read 2026-08-27
    what it says
    “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.”
  3. Sharifi-Rad et al., Carvacrol and human health: A comprehensive review (Phytother Res 2018, PMID 29744941) · read 2026-08-27
    what it says
    “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.”
  4. Imran et al., Therapeutic application of carvacrol: A comprehensive review (Food Sci Nutr 2022, PMID 36348778) · read 2026-08-27
    what it says
    “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.”
  5. 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.) · read 2026-08-27
    what it says
    “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.”
  6. 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) · read 2026-08-27
    what it says
    “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.”
  7. iHerb Singapore — Oregano Oil category page, default listing order · read 2026-08-27
    what it says
    “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”
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Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.