Natural Ingredient Research & Evidence
How much human research exists on natural ingredients such as honey, algae, oils, clays and charcoal, what reviews found, and how to read a study without being misled by counts.
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. This page describes research. It does not say that any ingredient treats a condition, and it does not replace advice from a clinician or pharmacist.
Evidence snapshot: how many records exist
The table counts records in PubMed, a large database of medical research run by the US National Library of Medicine. Each count comes from a plain-word search, so it can also include honeybee biology, food science, hospital uses of a chemical, and diet studies. A count shows how much has been published. It does not show whether something works or whether the studies were good. [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.
For a longer reading of the table, see research by ingredient.
What reviews found
Each finding below applies to the product, people and outcome named. Labels follow the library's standard set.| Question | What the review found | Evidence label |
|---|---|---|
| Honey applied to wounds | A Cochrane review pooled 26 trials with 3,011 people. It reported high-quality evidence that honey dressings healed partial-thickness burns faster than conventional dressings, and said evidence for most other comparisons was of low or very low quality. [2] | Promising but limited (high-quality evidence for one burn comparison only) |
| Honey for cough in children aged 12 months to 18 years | A Cochrane review of six trials (899 children) found no strong evidence for or against honey. [3] A later review rated the evidence low to very low. [4] | Promising but limited |
| Chlorella and spirulina and blood pressure or blood fats | A meta-analysis found a neutral effect for chlorella and a small spirulina effect on blood pressure of uncertain clinical significance. [5] | Mixed |
| Royal jelly and blood-sugar markers | A meta-analysis of five trials found no benefit on markers of blood sugar. [6] | No good evidence of benefit (for this outcome) |
| "Detox" diets and cleanses | NCCIH reported no compelling research for weight management or removing toxins, and low-quality studies. [7] | No good evidence of benefit |
How to read studies of natural ingredients
- Which exact product? A medical honey dressing, honey as a food and a supplement are different products.
- Human or lab? Laboratory activity is not a treatment result. See human, animal and laboratory research.
- Who paid? The honey wound review discloses that a trial it included received a contribution from a dressing manufacturer, and two authors of the algae meta-analysis are employed by a company named in the paper. [2][5]
- Negative results count. A trial that finds no effect is a finding, not a failure.
- Quality of claims. NCCIH notes that strong evidence behind supplement claims is often lacking. In one review of 27 ingredients promoted for immune function, rigorous human studies were found for only eight. [8]
Related pages
Human clinical studies, research limitations and traditional use versus clinical evidence.Frequently asked questions
Do natural remedies work?
It depends on the ingredient, the product and the question. Reviews we read found benefit for some narrow uses (for example honey dressings and partial-thickness burns), unclear results for others (cough in children) and no benefit for some (royal jelly and blood-sugar markers). [2][3][6]
Does a large number of PubMed records mean an ingredient is proven?
No. A count includes studies on other topics and studies that found no effect. It shows how much has been published, not whether something works. [1]
Do detox products remove toxins?
NCCIH found no compelling research that detox diets remove toxins or help weight management. [7] See detox claims checked.
Why do reviews of the same ingredient sometimes disagree?
They can include different trials, populations and outcomes, and can rate quality differently. Two reviews of honey for children's cough described the evidence differently. [3][4]
Where is the proof that something is safe?
Lack of evidence is not proof of safety. For a product-specific answer, ask a pharmacist or clinician and see the safety pages linked above.
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.
- National Center for Complementary and Integrative Health (NIH). "Detoxes" and "Cleanses": What You Need To Know. Last updated March 2025. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Read 2026-10-23.