Is aloe vera good for burns, gut health and blood sugar?

Aloe gel is best known as a skin remedy, but the controlled-trial evidence is mixed. A 1999 systematic review of ten controlled trials found that topical aloe vera is not an effective preventative for radiation-induced skin injury, that it might be effective for genital herpes and psoriasis, and that whether it promotes wound healing is unclear¹. A 2009 review of 40 dermatology-focused studies reported that topical aloe vera has no sunburn or suntan protection, but can be effective for genital herpes, psoriasis, human papilloma virus, seborrheic dermatitis, mouth ulcers (aphthous stomatitis), dry skin, lichen planus, frostbite, burns, wound healing, and inflammation. Both reviews warn that there are major caveats with these statements and that the clinical effectiveness of topical aloe is not yet sufficiently explored².

Internal Uses — Emerging Evidence

Gut Health

A randomized, double-blind, placebo-controlled trial of oral aloe vera gel in patients with mildly to moderately active ulcerative colitis found a clinical response more often with aloe than with placebo (47% vs. 14%). Clinical remission occurred in 30% of the aloe group and 7% of the placebo group, but that difference was not statistically significant, and the trial was small³. Reports of IBS symptom relief with aloe are anecdotal, and IBS-specific trials are lacking.

Blood Sugar

A systematic review and meta-analysis of five randomized trials in people with prediabetes or early untreated diabetes found that aloe vera supplementation lowered fasting blood glucose and HbA1c, but the authors judged the trials small and of poor quality, so the results are inconclusive⁴. A separate meta-analysis of oral aloe vera in people with prediabetes or diabetes reported larger reductions, but found signs of publication bias for fasting glucose⁵.

Topical Aloe: Two Reviews

Vogler and Ernst (1999) searched four databases for controlled clinical trials of aloe vera on any indication and found ten studies¹. They concluded that oral aloe might be a useful adjunct for lowering blood glucose in diabetic patients and for reducing blood lipids in patients with hyperlipidemia; that topical aloe is not an effective preventative for radiation-induced injuries; that it might be effective for genital herpes and psoriasis; and that whether it promotes wound healing is unclear. They added that there are major caveats with all of these statements and that, although some results are promising, clinical effectiveness is not sufficiently defined.

Feily and Namazi (2009) systematically summarized 40 dermatology-oriented experiments and trials of aloe vera preparations². Oral aloe in mice was effective for wound healing and reduced the number and size of papillomas and tumor incidence, and the same review found that topical aloe can be effective for genital herpes, psoriasis, human papilloma virus, seborrheic dermatitis, aphthous stomatitis, xerosis (dry skin), lichen planus, frostbite, burns, wound healing, and inflammation. Topical aloe had no sunburn or suntan protection and was not an effective prevention for radiation-induced injuries. The authors conclude that the clinical effectiveness of oral and topical aloe is not sufficiently and meticulously explored.

Ulcerative Colitis RCT: Langmead et al. (2004)

Langmead and colleagues randomized 44 evaluable hospital outpatients with mildly to moderately active ulcerative colitis in a 2:1 ratio to oral aloe vera gel or placebo, 100 mL twice daily for 4 weeks³. The primary outcomes were clinical, sigmoidoscopic, and histological remission. Clinical remission, improvement, and response occurred in 30%, 37%, and 47% of the 30 patients given aloe vera, compared with 7%, 7%, and 14% of the 14 patients given placebo. Only the response comparison reached statistical significance (P < 0.05, odds ratio 5.3, 95% CI 1.0 to 27); remission (P = 0.09) and improvement (P = 0.06) did not. The Simple Clinical Colitis Activity Index and histological scores decreased significantly with aloe vera (P = 0.01 and P = 0.03) but not with placebo. Sigmoidoscopic scores and laboratory variables did not differ significantly between aloe and placebo. Adverse events were minor and similar in both groups. The authors concluded that oral aloe vera taken for 4 weeks produced a clinical response more often than placebo, reduced histological disease activity, and appeared to be safe, and that further evaluation is needed.

Blood Sugar: Two Meta-Analyses

Zhang et al. (2016) pooled five randomized trials involving 415 participants with prediabetes or early untreated diabetes⁴. Compared with controls, aloe vera lowered fasting blood glucose (weighted mean difference −30.05 mg/dL, 95% CI −54.87 to −5.23; p = 0.02), HbA1c (−0.41%, 95% CI −0.55 to −0.27; p < 0.00001), triglycerides, total cholesterol, and LDL cholesterol, and raised HDL cholesterol (p = 0.04). Only one adverse event was reported, but the authors note that evidence about safety is limited and that, given the small number and poor quality of the trials, the results are inconclusive; a large, well-designed trial is needed.

Dick et al. (2016) meta-analyzed nine studies (283 participants) for fasting blood glucose, five of which (89 participants) also reported HbA1c⁵. Oral aloe vera lowered fasting glucose by 46.6 mg/dL (p < 0.0001) and HbA1c by 1.05% (p = 0.004); the data suggested greater benefit in patients with fasting glucose of 200 mg/dL or more. The Egger test showed publication bias for fasting glucose but not for HbA1c. The authors conclude that more robust and better-controlled studies are warranted.

Aloe Gel vs. Aloe Latex — A Critical Distinction

This is the single most important thing to understand about aloe vera. The leaf contains two distinct substances:

• Aloe gel — the clear, viscous inner fillet. This is the part studied in the trials above.
• Aloe latex — the yellow liquid found just beneath the outer leaf skin. This contains aloin (barbaloin), an anthraquinone compound that acts as a harsh stimulant laxative. Chronic use of aloe latex has been linked to electrolyte imbalances and potential kidney issues. The FDA removed aloe latex laxative products from the over-the-counter market in 2002 due to insufficient safety data.

For internal use, only consume inner fillet gel products that are decolorized (aloin-removed) or clearly labeled as latex-free.

Fresh Plant vs. Commercial Products

Many commercial "aloe vera" products contain minimal actual aloe. Some list it as the first ingredient but use reconstituted powder at low concentrations, padded with thickeners and preservatives. Products certified by the International Aloe Science Council (IASC) that list the aloe gel concentration clearly are easier to compare, and the trials above used specific gel preparations rather than generic cosmetic products.