Research by Ingredient: Evidence Snapshot Table
A PubMed record-count table for honey, algae, oils, clays, charcoal and other natural ingredients, with a guide to what the counts do and do not show.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read natural ingredient safety before you use anything on this page.
Information only. The table below counts published records. It is not a ranking, and it does not say that any ingredient treats a condition.
What this table shows
Each row is a search of PubMed, a large database of medical research run by the US National Library of Medicine. The columns give the number of records tagged as randomized controlled trials, the number tagged as any clinical trial, and the number of all records that mention the term. Counts were taken on 2026-10-22, and each row has a link so you can run the same search yourself. [1]| Ingredient | Records tagged as randomized controlled trials | Records tagged as any clinical trial | All PubMed records that mention it | Check it yourself |
|---|---|---|---|---|
| Honey | 269 | 315 | 19,602 | PubMed search |
| Manuka honey | 44 | 47 | 959 | PubMed search |
| Propolis | 134 | 161 | 5,660 | PubMed search |
| Royal jelly | 28 | 32 | 1,512 | PubMed search |
| Bee pollen | 3 | 3 | 749 | PubMed search |
| Spirulina | 87 | 106 | 4,271 | PubMed search |
| Chlorella | 29 | 38 | 9,767 | PubMed search |
| Seaweed / sea moss / kelp | 80 | 100 | 13,572 | PubMed search |
| Apple cider vinegar | 5 | 6 | 171 | PubMed search |
| Cacao / cocoa | 308 | 346 | 6,196 | PubMed search |
| Oats / colloidal oatmeal | 65 | 81 | 665 | PubMed search |
| Coconut oil | 125 | 147 | 2,913 | PubMed search |
| Olive oil | 1107 | 1218 | 14,848 | PubMed search |
| Castor oil | 55 | 80 | 2,860 | PubMed search |
| Jojoba | 12 | 20 | 305 | PubMed search |
| Shea butter | 10 | 13 | 157 | PubMed search |
| Mastic gum | 17 | 21 | 499 | PubMed search |
| Shilajit | 7 | 9 | 122 | PubMed search |
| Bentonite / kaolin clay | 73 | 111 | 7,828 | PubMed search |
| Activated charcoal | 189 | 238 | 3,922 | PubMed search |
| Epsom salt / magnesium sulfate | 591 | 689 | 5,350 | PubMed search |
Counted 2026-10-22 using NCBI E-utilities. Counts include studies of extracts, blends and non-health topics, and a trial can find no effect. A higher count means more human research has been indexed, not that something works.
How to read the counts
- A count is volume, not proof. A trial can find no effect, and a record can be about something other than health in people.
- The search term is just words. Each query looks for the words in a title or abstract. The query for honey is the single word "honey", the one for seaweed also includes "sea moss", "kelp" and "macroalgae", and the one for clay combines "bentonite" and "kaolin". [1] So a row can include food science, farming, industrial or hospital uses of a substance, and studies of products that are not the one you are considering.
- The trial columns count only tagged records. A study that does not carry the randomized-controlled-trial tag is not counted in that column.
- Large numbers can mean other things. In this table, for example, olive oil has by far the most trial-tagged records, and bee pollen has 3 trial-tagged records out of 749 that mention it. [1] The large olive oil number may partly reflect diet studies that mention the oil; the bee pollen numbers show how few trials are indexed for that term.
What the human research looks like where we read reviews
This table covers only the ingredients where we read a review or trial summary for this library. For the others, open the ingredient's own page.| Ingredient | What the source found | Evidence label | Where to read more |
|---|---|---|---|
| Honey (wounds) | High-quality evidence for faster healing of partial-thickness burns versus conventional dressings in one comparison; low or very low quality for most others. [2] | Promising but limited | More about Honey (wounds) → |
| Honey (children's cough) | No strong evidence for or against; low-quality evidence in a 2023 review. [3][4] | Promising but limited | More about Honey (children's cough) → |
| Spirulina and chlorella | Neutral effect for chlorella; small spirulina blood-pressure effect of uncertain significance. [5] | Mixed | More about Spirulina and chlorella → |
| Royal jelly | No benefit on markers of blood sugar in five trials. [6] | No good evidence of benefit (this outcome) | More about Royal jelly → |
| Castor oil | Three small trials of labor induction found no evidence of a difference from placebo or no treatment; nausea in all who swallowed it. [7] | Insufficient evidence | More about Castor oil → |
| Coconut and olive oil | One small trial in atopic dermatitis; see the oils pages. [8] | Insufficient evidence | Coconut oil, olive oil |
| Detox products | No compelling research for removing toxins or weight management. [9] | No good evidence of benefit | More about Detox products → |
This page does not summarize human evidence for the other rows of the snapshot (propolis, bee pollen, seaweed, apple cider vinegar, cacao, oats, jojoba, shea butter, mastic, shilajit, clays, charcoal and Epsom salt). We did not review them for this page, so it makes no claim either way; each has its own page that states what was read. See the A to Z directory.
Related pages
Research overview, human clinical studies and research limitations.Frequently asked questions
Which natural ingredient has the most research?
The table shows how many records exist for each search term, not which ingredient works best. We do not rank ingredients. [1]
Why does olive oil have so many records?
The search term matches the words "olive oil" in titles and abstracts, which can include diet and food studies as well as studies of skin use. [1]
Does a low count mean an ingredient does not work?
No. It means fewer records were indexed for that search. Bee pollen has few trial-tagged records, which is a gap in the evidence, not proof of harm or of benefit. [1]
Can I check the numbers myself?
Yes. Each row links to a PubMed search using the same terms.
Where do I find safety information for one ingredient?
Open the ingredient's page from the A to Z directory and read natural ingredient safety.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
References
- National Library of Medicine. PubMed, searched through NCBI E-utilities on 2026-10-22 for the counts shown in the snapshot table on this page (search terms are shown by each row's PubMed link). Counts file read 2026-10-23.
- Jull AB, Cullum N, Dumville JC, Westby MJ, Deshpande S, Walker N. Honey as a topical treatment for wounds. Cochrane Database Syst Rev. 2015;(3):CD005083. PubMed 25742878. Several authors were investigators in an included trial that received a small contribution from a honey-dressing manufacturer (disclosed in the review). Read 2026-10-23.
- Oduwole O, Udoh EE, Oyo-Ita A, Meremikwu MM. Honey for acute cough in children. Cochrane Database Syst Rev. 2018;4(4):CD007094. PubMed 29633783. Read 2026-10-23.
- Kuitunen I, Renko M. Honey for acute cough in children - a systematic review. Eur J Pediatr. 2023;182(9):3949-3956. PubMed 37355498. Read 2026-10-23.
- Pinto-Leite M, et al. The Role of Chlorella and Spirulina as Adjuvants of Cardiovascular Risk Factor Control: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Nutrients. 2025;17(6):943. PubMed 40289965. Two authors are employed by a company (Sea4Us) named in the paper. Read 2026-10-23.
- Mahboobi S, Jafarnejad S, Eftekhari MH. Royal jelly does not improve markers of glycemia: A systematic review and meta-analysis of randomized clinical trials. Complement Ther Med. 2019;44:235-241. PubMed 31126561. Read 2026-10-23.
- Kelly AJ, Kavanagh J, Thomas J. Castor oil, bath and/or enema for cervical priming and induction of labour. Cochrane Database Syst Rev. 2013;(7):CD003099. PubMed 23881775. Read 2026-10-23.
- Verallo-Rowell VM, Dillague KM, Syah-Tjundawan BS. Novel antibacterial and emollient effects of coconut and virgin olive oils in adult atopic dermatitis. Dermatitis. 2008;19(6):308-15. PubMed 19134433. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). "Detoxes" and "Cleanses": What You Need To Know. Last updated March 2025. Read 2026-10-23.