Aloe Vera: Benefits, Forms, Dosing, and Side Effects

Aloe vera has been used medicinally for thousands of years. The inner leaf gel and outer leaf latex have distinct properties and very different safety profiles. While aloe gel is generally safe and shows preliminary benefits for GERD, blood sugar, and topical skin conditions, aloe latex carries significant risks including potential carcinogenicity. Understanding the difference between gel and latex is critical for safe use.

Table of Contents

• Overview
• Forms and Bioavailability
• Evidence for Benefits
• Recommended Dosing
• Safety and Side Effects
• Drug Interactions
• Dietary Sources and Quality Considerations
• Toxicity Studies and Safety Reviews
• References

Overview

Aloe vera (typically labeled as Aloe barbadensis) is a short-stemmed, cactus-like succulent plant with thick, fleshy leaves that has been used medicinally for thousands of years. Historical records document its use in ancient Greece, Rome, Babylonia, and China for skin conditions, wound healing, and digestive ailments [1][2]. The plant is now grown commercially in subtropical regions around the world, including the southern border areas of Texas, New Mexico, Arizona, and California [2].

The aloe leaf contains two distinct bioactive zones, each with different compositions and clinical applications [1][3]:

• Aloe gel — derived from the inner leaf. Although mostly water (>98%), it contains polysaccharide compounds, most notably acemannan (acetylated mannose), which is considered the primary bioactive component. Acemannan has demonstrated immunomodulatory, anti-inflammatory, and wound-healing properties in laboratory and animal studies [1][3].
• Aloe latex — found in the outer portion of the leaf, beneath the skin. Contains anthraquinone compounds, primarily aloins (including aloin A and aloin B) and emodin. Aloe latex acts as a potent stimulant laxative. Products made from whole aloe leaf or unpurified aloe leaf juice will contain these latex compounds [1][3].

This distinction between gel and latex is clinically important because the safety profiles differ markedly. Aloe gel is generally considered safe for both oral and topical use in moderate amounts, while aloe latex raises serious safety concerns including potential carcinogenicity (see Safety and Side Effects) [1][2][3].

Most commercial aloe products are made with Aloe barbadensis, but other species may be used, such as Aloe ferox (Cape aloe), which contains higher concentrations of latex [1]. Additional species include Aloe africana and Aloe arborescens [2]. The species should be noted on the product label.

Aloe vera is marketed for a wide range of uses. Topically, it is promoted for burns, sunburn, wound healing, acne, psoriasis, lichen planus, oral submucous fibrosis, genital herpes, and skin damage from radiation therapy [1][2]. Orally, it is promoted for constipation, gastroesophageal reflux disease (GERD), blood sugar regulation, weight loss, inflammatory bowel disease (including ulcerative colitis and Crohn's disease), irritable bowel syndrome (IBS), and osteoarthritis [1][2][3].

In 2002, the U.S. Food and Drug Administration (FDA) issued a ruling that required manufacturers to remove aloe latex from over-the-counter laxative products, deeming aloe "not generally safe and effective" for this use due to a lack of adequate safety data [1][2][3]. The International Agency for Research on Cancer (IARC) of the World Health Organization has classified non-decolorized whole leaf extract of aloe vera as "possibly carcinogenic to humans" (Group 2B) [2][3][4].

Despite these regulatory concerns, aloe vera remains one of the most widely consumed botanical supplements globally, available as juices, gels, capsules, powders, and topical preparations.

Forms and Bioavailability

Types of Aloe Products

The clinical effects of aloe vera depend critically on the type of preparation used. The following table summarizes the major forms:

Form	Source	Key Compounds	Typical Use	Latex Content
Aloe Vera Gel	Inner leaf	Acemannan, polysaccharides, vitamins, minerals, amino acids	Topical (burns, wound healing); Oral (blood sugar, GI)	Very low
Aloe Vera Juice (Purified/Decolorized)	Whole leaf, filtered	Polysaccharides; latex largely removed	Oral health supplement	<10 ppm aloin (IASC standard)
Aloe Vera Juice (Unpurified/Raw)	Whole leaf, unfiltered	Polysaccharides + aloins + emodin	Laxative; oral supplement	High
Aloe Latex	Outer leaf (under skin)	Aloins (aloin A, aloin B), emodin, anthraquinones	Stimulant laxative	Very high
Aloe Vera Cream/Ointment	Gel extract in topical base	Standardized aloe extract (typically 0.5%)	Skin conditions (herpes, psoriasis)	Variable
Dried Aloe Extract/Powder	Concentrated gel or whole leaf	Concentrated polysaccharides ± aloins	Capsules, tablets	Depends on processing
Aloe Ferox (Cape Aloe)	Aloe ferox species	Higher latex/aloin content than A. barbadensis	Stronger laxative effect	Very high

Processing and Decolorization

The safety and composition of aloe products depends heavily on processing [1][3]:

• Decolorized (purified) aloe has undergone filtration or activated carbon treatment to remove the yellowish latex containing anthraquinone compounds. Products labeled as "filtered," "purified," or "decolorized" should contain minimal latex.
• Non-decolorized aloe retains the full latex content, including aloins and emodin. This is the form classified as "possibly carcinogenic" by IARC [2][4].
• The International Aloe Science Council (IASC) certification program requires certified aloe products for internal consumption to contain less than 10 parts per million (ppm) of aloin [1].

Key Bioactive Compounds

Acemannan is the primary bioactive polysaccharide in aloe vera gel, consisting of acetylated mannose units. It has demonstrated immunomodulatory properties, stimulating macrophage activity and cytokine production in laboratory studies [3]. However, many commercial aloe products do not list their acemannan content, and independent testing has found that some products contain little or no acemannan [1].

Aloins (anthraquinone glycosides) are the primary active compounds in aloe latex. Aloin is converted by gut bacteria to aloe-emodin, which stimulates colonic motility and fluid secretion, producing the laxative effect [1][3].

Other compounds present in aloe gel include vitamins (A, C, E, B12, folic acid), minerals (calcium, chromium, copper, selenium, magnesium, manganese, potassium, sodium, zinc), enzymes (amylase, lipase, alkaline phosphatase), amino acids, salicylic acid, lignin, and saponins [3].

Bioavailability Considerations

Limited human bioavailability data exist for orally consumed aloe vera compounds. The polysaccharides in aloe gel are large molecular weight molecules, and their absorption from the gastrointestinal tract is not well characterized. Most evidence for systemic effects comes from clinical outcome studies rather than pharmacokinetic research.

For topical preparations, the aloe gel matrix appears to enhance skin penetration of active compounds, though the degree of absorption through intact skin varies by formulation. Standardized cream preparations (e.g., 0.5% aloe extract) used in clinical trials for herpes and psoriasis represent a specific concentration, distinct from applying pure aloe gel directly from the plant [1].

Evidence for Benefits

Constipation (Laxative Effect)

Aloe vera juice containing latex reliably produces a laxative effect due to the anthraquinone compounds (aloins), which act as stimulant laxatives by increasing colonic motility and fluid secretion [1][3].

The mechanism involves bacterial conversion of aloin to aloe-emodin in the large intestine, which stimulates peristalsis and inhibits water and electrolyte reabsorption, producing softer, more frequent stools [3].

However, the FDA banned aloe latex in over-the-counter laxative products in 2002, requiring manufacturers to remove it from OTC formulations due to insufficient safety and efficacy data meeting modern regulatory standards [1][2][3]. This does not mean the laxative effect is absent — rather, the FDA determined there was inadequate data to classify it as both safe and effective for OTC drug use.

For constipation, aloe is typically taken in the evening. The dose ranges from 50 to 200 mg of dried aloe juice (as an extract or powder), or one tablespoon of aloe juice up to three times per day [1]. A number of other supplements, including those providing fiber (such as psyllium husk), may be safer and helpful alternatives for constipation [1].

Gastroesophageal Reflux Disease (GERD)

An open-label study in Iran among 79 people (average age 47) with GERD evaluated aloe vera gel syrup (standardized to 5.0 mg of polysaccharide per mL of syrup) at a dose of 10 mL (0.34 fl oz) once daily for 4 weeks [1].

Key findings from Panahi et al. (J Tradit Chin Med, 2015) [5]:

• Aloe vera gel syrup significantly reduced self-reported GERD symptoms compared to baseline, including heartburn, food and acid regurgitation, difficulty swallowing, flatulence, belching, nausea, and vomiting
• Aloe syrup was as effective as omeprazole (20 mg once daily) and ranitidine (150 mg twice daily) at reducing regurgitation, nausea, and vomiting
• However, aloe was less effective than both drugs at reducing heartburn and flatulence
• Study limitations: open-label design (no blinding), relatively small sample (n=79), short duration (4 weeks), single-center

This remains the only clinical trial evaluating aloe for GERD. While the results are encouraging, the open-label design means placebo effects cannot be excluded, and the finding that aloe was inferior to standard medications for the primary symptom of heartburn limits its clinical utility as a standalone treatment.

Blood Sugar and Diabetes

Preliminary evidence suggests that consuming aloe vera gel or juice shortly after eating slightly reduces the normal postprandial rise in blood sugar levels [1][2].

Postprandial glucose reduction: Thilavech et al. (J Funct Food, 2024) [6] found that aloe vera gel consumption after meals modestly reduced the normal rise in blood sugar, though effects on triglycerides and free amino acids were not significant.

Type 2 diabetes: Huseini et al. (Planta Med, 2012) [7] conducted a randomized double-blind placebo-controlled clinical trial in hyperlipidemic type 2 diabetic patients and reported anti-hyperglycemic and anti-hypercholesterolemic effects of aloe vera leaf gel. The study found modest reductions in fasting blood glucose and postprandial glucose.

Weight and metabolic parameters: The NIH notes that a small study showed a specific aloe gel product taken orally for 8 weeks modestly reduced weight and fat mass in adults with obesity or overweight who had diabetes or prediabetes [2].

HbA1c: A small amount of research suggests that aloe taken orally may reduce blood sugar and HbA1c (a marker of long-term blood sugar control) in people with diabetes [2].

Limitations: These studies are small, short-term, and preliminary. There have been no large, long-term, randomized, controlled clinical trials demonstrating clinically meaningful improvements in glycemic control with aloe vera. People with diabetes should be aware that aloe may potentially cause blood sugar levels to fall too low, particularly when used alongside diabetes medications (see Drug Interactions) [1][3].

Ulcerative Colitis

Langmead et al. (Aliment Pharmacol Ther, 2004) [8] conducted a randomized, double-blind, placebo-controlled trial of aloe vera gel for mild to moderate ulcerative colitis:

• Design: 44 patients randomized to oral aloe vera gel (100 mL twice daily) or placebo for 4 weeks
• Results: Clinical remission, clinical improvement, and simple clinical colitis activity index (SCCAI) scores improved more in the aloe group than placebo, though the study was small
• Histological improvement was also observed in the aloe group
• Limitations: Small sample size (n=44), short duration (4 weeks), single-center study

This remains the only published RCT of aloe for ulcerative colitis. While the results showed promise, the evidence is considered preliminary and insufficient to recommend aloe as a treatment for inflammatory bowel disease [1][2].

Irritable Bowel Syndrome (IBS)

Davis et al. (Int J Clin Pract, 2006) [9] evaluated decolorized aloe leaf extract for diarrhea-predominant IBS:

• Design: Randomized double-blind placebo-controlled trial with patients receiving 50 mL of decolorized aloe leaf extract taken four times daily for one month
• Results: Some improvement in IBS symptoms was reported
• Limitations: No large, long-term, randomized, controlled clinical studies have confirmed these findings [1]

The evidence for aloe in IBS remains insufficient for clinical recommendations [2].

Burns and Sunburn

Although aloe vera gel is one of the most commonly used home remedies for sunburn and other burns, the clinical evidence is mixed [1][2].

Positive evidence: The NIH states that clinical research suggests topical application of aloe gel may speed burn healing and reduce burn-related pain [2]. Mahboub et al. (J Caring Sci, 2021) [10] conducted a randomized clinical trial comparing aloe vera gel with silver sulfadiazine cream 1% for burn wound healing and found potential benefits for aloe in healing, itching, and pain management. Sharma et al. (Adv Skin Wound Care, 2022) [11] published a meta-analysis and systematic review of second-degree burns and aloe vera, contributing to the evidence base for burn applications.

Limitations: Despite widespread use, there are no large, high-quality RCTs definitively establishing aloe's superiority over standard wound care for burns. The evidence base consists primarily of small trials with heterogeneous methodologies [1][2].

Radiation Dermatitis

Aloe vera has been applied to the skin of patients receiving radiation therapy for cancer, but the evidence indicates it is not effective for this use [1].

Clinical studies have found that topical aloe vera does not significantly reduce redness, itching, or peeling associated with radiation therapy-induced skin damage [1][2]. Despite its continued recommendation in some complementary medicine resources, the clinical trial data do not support its use for radiation dermatitis.

Genital Herpes

Some preliminary evidence suggests that a topical cream containing 0.5% aloe extract (as opposed to pure aloe gel) may be effective for treating genital herpes lesions [1][2].

In clinical studies, topical aloe vera cream containing 0.5% aloe extract was applied three times daily to herpes lesions. The cream preparations showed potential for accelerating healing time [1]. Note that this is a specific standardized extract concentration, not raw aloe gel applied directly.

The evidence remains preliminary and limited to small studies. Standard antiviral medications (e.g., acyclovir, valacyclovir) remain the mainstay of herpes treatment [1][2].

Psoriasis

Evidence for aloe vera cream in treating psoriasis is mixed [1][2].

Some studies using topical aloe preparations have reported improvements in psoriasis symptoms, including reduced scaling and erythema (redness). However, other studies have failed to replicate these findings, and the overall evidence base is inconsistent [1][2].

The NIH notes that a small amount of research suggests topical use of aloe may help people with psoriasis, but the quality of evidence is limited [2].

Lichen Planus

Several studies have shown benefits of topical aloe gel for relieving symptoms of lichen planus, a skin condition characterized by itchy, flat, scaly patches [1].

Lichen planus can affect the skin, mouth, and other mucosal surfaces. Aloe gel has been studied as a topical treatment for oral lichen planus, with some studies demonstrating reduced pain, burning sensation, and clinical improvement compared to placebo [1][2].

While the evidence is more consistent here than for some other indications, the studies remain small and additional research is needed.

Oral Submucous Fibrosis

Oral submucous fibrosis is a chronic condition causing scarring, tissue fibrosis, and a burning sensation in the mouth. Al-Maweri et al. (J Oral Pathol Med, 2019) [12] published a systematic review and meta-analysis evaluating aloe vera in the treatment of this condition.

The NIH notes that a small amount of research suggests topical aloe may help people with oral submucous fibrosis [2]. The evidence base is growing but still limited.

Acne

Two small studies suggest that topical application of aloe gel, in combination with other forms of treatment, may improve acne [2].

Zhong et al. (Front Med, 2021) [13] evaluated aloe vera gel combined with ultrasound and soft mask for the treatment of mild to severe facial acne and reported positive results. However, because aloe was used as part of a combination therapy, its independent contribution to the observed benefits is difficult to isolate.

Seborrhea

An ointment made of aloe vera may reduce symptoms of seborrhea (seborrheic dermatitis), which presents as red, scaly skin eruptions typically on the scalp, face, and chest [1]. The evidence is limited to small studies.

Wound Healing

Several studies have evaluated topical aloe in wound healing, and the results have been mixed [1][2]. Long (JAMA Dermatol, 2016) [14] reviewed aloe vera's historical use in dermatology, noting both traditional applications and the inconsistency of modern evidence.

Notably, one study suggested that aloe vera can actually impair wound healing, raising concerns about its routine application to surgical wounds or other non-burn injuries [1].

The NIH notes interest in using aloe for diabetic foot ulcers, but there is insufficient reliable evidence to determine whether it is helpful for this condition [2].

Osteoarthritis

Taking aloe orally has been proposed as a treatment for osteoarthritis due to aloe's potential anti-inflammatory action [1].

Cowan (Br J Community Nurs, 2010) [15] discussed the rationale for using aloe in osteoarthritis management. However, there have been no large, long-term, randomized, controlled clinical studies evaluating aloe gel for osteoarthritis [1], and the evidence remains speculative.

Weight Loss

The NIH notes that oral use of aloe is promoted for weight loss [2]. A small study showed that a specific aloe gel product taken orally for 8 weeks modestly reduced weight and fat mass in adults with obesity or overweight who had diabetes or prediabetes [2].

However, the evidence is too limited to recommend aloe vera for weight management.

Eye Health (Dry Eye)

Placing aloe in the eye is recommended on some websites as a home remedy for dry eye. However, this recommendation appears to be based solely on a single laboratory (in vitro) study [1].

Wozniak and Paduch (Pharm Biol, 2012) [16] studied cells from the cornea of the eye and found that certain ethanol and ethyl acetate extracts of aloe reduced markers of inflammation and had free radical scavenging effects in the laboratory setting.

Animal studies using aloe to treat corneal lesions and burns have yielded mixed results: Green et al. (J Toxicol Cutaneous Ocul Toxicol, 2008) [17] reported mixed outcomes, and Atiba et al. (Clin Ophthalmol, 2015) [18] also found inconsistent results.

There is no clinical evidence supporting the use of aloe in the eye, and self-treating with non-sterile plant preparations carries a risk of eye infection and irritation.

Recommended Dosing

There is no established standard dose for aloe vera, as the appropriate amount depends on the form, preparation method, and intended use. The following dosing information is derived from clinical studies and expert guidance [1]:

By Indication

Indication	Form	Dose	Frequency	Duration Studied
Constipation	Dried aloe juice (extract/powder)	50-200 mg	Once daily (evening)	Short-term only
Constipation	Aloe juice (liquid)	1 tablespoon (~15 mL)	Up to 3 times daily	Short-term only
GERD	Aloe vera gel syrup (5.0 mg polysaccharide/mL)	10 mL	Once daily	4 weeks
Blood sugar management	Aloe vera gel	1 tablespoon (~15 mL)	Once daily	Varies
Genital herpes (topical)	0.5% aloe cream	Applied to lesions	3 times daily	Until healing
Ulcerative colitis	Aloe vera gel (oral)	100 mL	Twice daily	4 weeks
IBS (diarrhea-predominant)	Decolorized aloe leaf extract	50 mL	4 times daily	1 month

Important Dosing Notes

• For laxative use, aloe latex products should only be used short-term. Chronic use of stimulant laxatives can lead to electrolyte imbalance, dependency, and colonic dysfunction [1][3].
• For oral supplementation, the NIH suggests that short-term use of oral aloe gel up to 42 days appears safe based on available research [2].
• Topical use of aloe gel has no established upper limit and is generally well tolerated, though patch testing is advisable for those with sensitive skin or known plant allergies [1][2].
• Quality variation is a significant concern. Most aloe products do not list their acemannan or aloin content, and independent testing has found that some products contain little or no acemannan [1]. The IASC certification seal provides some quality assurance for products intended for internal use (<10 ppm aloin) [1].

Safety and Side Effects

Aloe Gel Safety

Aloe vera gel is generally considered safe when taken orally in small doses and when applied topically [1][2].

Oral use: Research studies suggest that short-term use of oral aloe gel up to 42 days is safe [2]. The primary concern with oral aloe gel is the potential to lower blood glucose levels, which could be problematic for people with diabetes or those taking hypoglycemic medications [1][3].

Topical use: Generally well tolerated. However, there have been occasional reports of burning, itching, rash, and eczema with topical application [2]. Some individuals may experience allergic contact dermatitis, particularly those with known allergies to plants in the Liliaceae family (which includes garlic and onions) [1][2].

Aloe Latex Safety — Serious Concerns

Products containing aloe vera latex carry significantly greater safety risks [1][2][3]:

Gastrointestinal effects: Aloe latex may cause diarrhea, which in turn can lead to electrolyte imbalance (particularly potassium depletion), kidney dysfunction, dry mouth, headache, and nausea [1][3].

Carcinogenicity concerns: Animal studies have shown that aloe latex may cause genetic mutations and be carcinogenic [1][2][3]. The evidence includes:

• The International Agency for Research on Cancer (IARC) classifies non-decolorized whole leaf extract of aloe vera as "possibly carcinogenic to humans" (Group 2B) [2][3][4]
• Some animal studies have noted an association between non-decolorized aloe vera leaf extract taken orally and gastrointestinal cancer in rats and mice [2]
• Most toxicity and safety studies in animals tested non-decolorized whole leaf extract, which is not commonly used by consumers [2]
• A small amount of laboratory research suggests that even decolorized extract might have the potential to damage DNA or chromosomes [2]

California Prop 65: On December 4, 2015, California's Office of Environmental Health Hazard Assessment (OEHHA) added non-decolorized whole leaf extract of aloe vera to the state's list of chemicals known to cause cancer, based on the IARC classification. Dietary supplements sold in California that contain this ingredient must include a warning [3]. The Prop 65 list does not include aloe vera decolorized whole leaf extract, aloe vera gel, or aloe vera gel extract [3].

2023 safety review: Kim et al. (Food Chem Toxicol, 2023) [19] reviewed animal and laboratory studies of aloe vera inner leaf gel extract and decolorized whole leaf extract used in commercially available food-grade drinkable products containing no more than 10 ppm of aloin. The authors concluded that these drinkable products were not genotoxic [2]. This provides some reassurance for consumers of properly processed aloe beverages, but does not extend to unprocessed or non-decolorized products.

FDA action: The FDA banned aloe latex in over-the-counter laxative drugs in 2002, deeming it "not generally safe and effective" [1][2][3].

Liver Toxicity

Rarely, liver injury associated with oral consumption of aloe vera extract has been reported [1][3]:

• From 2005 to 2016, approximately 12 published case reports of liver toxicity (elevated liver enzymes, jaundice, acute hepatitis) were documented worldwide in association with consuming aloe vera extract [3]
• Liver injury typically occurred between 3 and 24 weeks after starting aloe vera supplementation [3]
• No specific components of aloe vera extract have been identified as hepatotoxic; researchers suspect that certain individuals may be "hypersensitive" or experience an idiosyncratic immune system reaction [3]
• Oral consumption of aloe leaf extracts (for as little as 3 weeks and as long as 5 years) has been related to cases of acute hepatitis [2]
• Most cases resolved when aloe vera extract supplementation was discontinued [3]

References: LiverTox, National Institute of Diabetes and Digestive and Kidney Diseases, 2017 [20]; Yang et al. (J Korean Med Sci, 2010) [21].

Contraindicated Populations

The following groups should avoid or use aloe products with extreme caution [1][2][3]:

• Pregnant or nursing women — Aloe in gel, latex, or whole leaf extract form, when taken by mouth, may be unsafe during pregnancy and breastfeeding [2]. If aloe vera is used topically on nipples, it should be washed off before nursing as this has been reported to interfere with feeding and cause diarrhea in infants [3][26].
• Children — Should not use latex-containing aloe products [3].
• Elderly — Should not use latex-containing aloe products [3].
• People with kidney disorders — Aloe latex should not be used due to the risk of electrolyte imbalance and potential kidney dysfunction [3].
• People with gastrointestinal disorders — Aloe latex may worsen existing GI conditions [3].
• People with hemorrhoids — Aloe latex is contraindicated [3].
• People with diabetes — Aloe may cause blood sugar levels to fall too low, particularly when used alongside diabetes medications [1][3].

Drug Interactions

Blood Sugar-Lowering Medications

Aloe vera gel may lower blood glucose levels, potentially causing additive hypoglycemia when taken alongside diabetes medications including insulin, metformin, sulfonylureas, and other glucose-lowering drugs [1][3]. Blood sugar should be monitored more closely if combining aloe with these medications.

Cardiac Glycosides (Digoxin)

Overuse of aloe latex (as a stimulant laxative) may increase the risk of adverse effects from cardiac glycosides such as digoxin. The mechanism involves latex-induced diarrhea leading to potassium depletion, which increases sensitivity to digoxin toxicity (potentially causing dangerous cardiac arrhythmias) [2][3].

Stimulant Laxatives

Combining aloe latex with other stimulant laxatives may increase the risk of electrolyte imbalance, particularly hypokalemia (low potassium) [3].

Diuretics

Concurrent use of aloe latex and diuretics may compound potassium loss, increasing the risk of hypokalemia and associated cardiac complications [3].

Anticoagulants and Antiplatelet Drugs

Some evidence suggests aloe may affect blood clotting. Patients on warfarin, heparin, aspirin, or other anticoagulant/antiplatelet medications should exercise caution and consult their healthcare provider before using aloe supplements [3].

Sevoflurane (Anesthetic)

Case reports suggest that aloe vera may interfere with the anesthetic sevoflurane, potentially affecting blood clotting during surgery. Patients should disclose aloe use to their anesthesiologist before surgical procedures [3].

General Recommendation

If you take any type of medication, talk with your healthcare provider before using aloe vera or other herbal products, as some herbs and medicines interact in harmful ways [2]. Discontinue oral aloe supplements at least 2 weeks before any scheduled surgery.

Dietary Sources and Quality Considerations

Natural Sources

Unlike vitamins and minerals that occur in a wide range of foods, aloe vera is not a common dietary component. It must be consumed as a supplement or applied topically.

The aloe vera plant can be grown at home in warm, dry environments. To extract the gel directly from a plant, cut a mature outer leaf, slice it open, and scoop out the clear inner gel. This method provides fresh aloe gel for topical use but offers no standardization of active compound content.

Choosing an Aloe Product

When selecting an aloe vera supplement, the key decision is whether you want aloe gel only (no latex) or a product that includes latex [1]:

If you want to avoid latex (most consumers):

• Look for products labeled "aloe vera gel," or aloe vera leaf juice that has been "filtered," "purified," or "decolorized" [1]
• Products with the IASC (International Aloe Science Council) certification seal must contain less than 10 ppm aloin for products intended for internal consumption [1]
• Avoid products labeled "whole leaf" unless they specify decolorization/purification

If you specifically want latex (laxative effect):

• Look for unprocessed or "raw" aloe vera juice [1]
• Products made from Aloe ferox (Cape aloe) species contain higher latex content [1]
• Use only short-term and be aware of the safety concerns outlined above

Quality Concerns

• Most aloe products do not list their amounts of acemannan or aloins [1]
• Independent testing has found that some products contain little or no acemannan — the primary bioactive compound in aloe gel [1]
• Third-party testing (such as by ConsumerLab.com or IASC certification) provides greater confidence in product quality [1]
• Look for products that specify the standardized content of polysaccharides or acemannan

The Aloe Vera Plant

Aloe vera (Aloe barbadensis) is a perennial succulent belonging to the family Asphodelaceae (formerly classified in Liliaceae). The plant features:

• Thick, fleshy, lance-shaped leaves arranged in a rosette pattern
• Leaves with serrated edges containing spiny teeth
• A central gel (inner leaf) surrounded by a thin layer of latex beneath the outer rind
• Yellow flowers on a spike when mature

The plant has been cultivated for over 6,000 years, with historical records from Egypt, Greece, and China documenting its medicinal use [3][14].

Toxicity Studies and Safety Reviews

Animal Studies

The most concerning safety data for aloe vera comes from animal toxicology studies:

• The National Toxicology Program (NTP) conducted two-year studies in rats and mice using non-decolorized whole leaf extract of aloe vera. These studies found clear evidence of carcinogenic activity, with increased incidence of tumors in the large intestine [4].
• Guo and Mei (J Environ Sci Health C, 2016) [22] published a comprehensive review of aloe vera toxicity and adverse clinical effects, noting the association between non-decolorized aloe extracts and genotoxicity in animal models.
• It is important to note that most toxicity studies tested non-decolorized whole leaf extract, which is not commonly used by consumers who purchase purified aloe gel products [2].

Genotoxicity Assessment

A small amount of laboratory research suggests that even decolorized aloe extract might have the potential to damage DNA or chromosomes, though this finding requires further investigation [2].

Kim et al. (Food Chem Toxicol, 2023) [19] reviewed the genotoxicity data specifically for commercially available food-grade aloe beverages (inner leaf gel extract and decolorized whole leaf extract with no more than 10 ppm aloin) and concluded these products were not genotoxic. This review provides the most relevant safety data for typical consumer products.

Key Safety Reviews and Regulatory Sources

Source	Assessment	Year
IARC (WHO)	Non-decolorized whole leaf extract classified as "possibly carcinogenic to humans" (Group 2B)	2016 [4]
U.S. FDA	Banned aloe latex in OTC laxative products; "not generally safe and effective"	2002 [3]
California Prop 65	Non-decolorized whole leaf extract added to carcinogen list	2015 [3]
NatMed Pro	Comprehensive safety and efficacy monograph	2023 [23]
Kim et al.	Food-grade decolorized aloe beverages (no more than 10 ppm aloin) are not genotoxic	2023 [19]
Pressman et al.	Review of safety at frontier of glycobiology and integrative medicine	2019 [24]

References

1. ConsumerLab. "Aloe Supplements Review." Accessed 2025. https://www.consumerlab.com/reviews/aloe-juicies-gels-and-supplements/aloe/

2. National Center for Complementary and Integrative Health (NCCIH). "Aloe Vera." Updated February 2025. https://www.nccih.nih.gov/health/aloe-vera

3. U.S. Food and Drug Administration. "Status of Certain Additional Over-the-Counter Drug Category II and III Active Ingredients." Federal Register. 2002;67(90):31125-31127.

4. International Agency for Research on Cancer (IARC). "Some Drugs and Herbal Products." IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 108. Lyon, France: IARC; 2016. https://ncbi.nlm.nih.gov/books/NBK350406/

5. Panahi Y, Khedmat H, Valizadegan G, et al. "Efficacy and safety of Aloe vera syrup for the treatment of gastroesophageal reflux disease: a pilot randomized positive-controlled trial." J Tradit Chin Med. 2015;35(6):632-636.

6. Thilavech T, et al. "Effect of aloe vera gel consumption on postprandial glycemic, lipidemic, and amino acid responses." J Funct Food. 2024.

7. Huseini HF, Kianbakht S, Hajiaghaee R, Dabaghian FH. "Anti-hyperglycemic and anti-hypercholesterolemic effects of Aloe vera leaf gel in hyperlipidemic type 2 diabetic patients: a randomized double-blind placebo-controlled clinical trial." Planta Med. 2012;78(4):311-316.

8. Langmead L, Feakins RM, Goldthorpe S, et al. "Randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis." Aliment Pharmacol Ther. 2004;19(7):739-747.

9. Davis K, Philpott S, Kumar D, Mendall M. "Randomised double-blind placebo-controlled trial of aloe vera for irritable bowel syndrome." Int J Clin Pract. 2006;60(9):1080-1086.

10. Mahboub M, Aghazadeh Attari AM, Sheikhalipour Z, et al. "A comparative study of the impacts of aloe vera gel and silver sulfadiazine cream 1% on healing, itching and pain of burn wounds: a randomized clinical trial." J Caring Sci. 2021;11(3):132-138.

11. Sharma S, Alfonso AR, Gordon AJ, et al. "Second-degree burns and aloe vera: a meta-analysis and systematic review." Adv Skin Wound Care. 2022;35(11):1-9.

12. Al-Maweri SA, Ashraf S, Lingam AS, et al. "Aloe vera in treatment of oral submucous fibrosis: a systematic review and meta-analysis." J Oral Pathol Med. 2019;48(2):99-107.

13. Zhong H, Li X, Zhang W, et al. "Efficacy of a new non-drug acne therapy: aloe vera gel combined with ultrasound and soft mask for the treatment of mild to severe facial acne." Front Med. 2021;8:662640.

14. Long V. "Aloe vera in dermatology — the plant of immortality." JAMA Dermatol. 2016;152(12):1364.

15. Cowan D. "Oral Aloe vera as a treatment for osteoarthritis: a summary." Br J Community Nurs. 2010;15(6):280-282.

16. Wozniak A, Paduch R. "Aloe vera extract activity on human corneal cells." Pharm Biol. 2012;50(2):147-154.

17. Green M, et al. "Toxicological evaluation of aloe vera in the eye." J Toxicol Cutaneous Ocul Toxicol. 2008.

18. Atiba A, et al. "Aloe vera and corneal wound healing." Clin Ophthalmol. 2015.

19. Kim S-T, Pressman P, Clemens R, et al. "The absence of genotoxicity of aloe vera beverages: a review of the literature." Food Chem Toxicol. 2023;174:113628.

20. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. "Aloe Vera." National Institute of Diabetes and Digestive and Kidney Diseases. 2017. https://www.ncbi.nlm.nih.gov/books/NBK548206/

21. Yang HN, Kim DJ, Kim YM, et al. "Aloe-induced toxic hepatitis." J Korean Med Sci. 2010;25(3):492-495.

22. Guo X, Mei N. "Aloe vera: a review of toxicity and adverse clinical effects." J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2016;34(2):77-96.

23. Aloe. NatMed Pro website. Accessed at naturalmedicines.therapeuticresearch.com on July 18, 2023. [Database subscription].

24. Pressman P, Clemens R, Hayes AW. "Aloe vera at the frontier of glycobiology and integrative medicine: health implications of an ancient plant." SAGE Open Med. 2019;7:2050312119875921.

25. Rodriguez S, Dentali S, Powell D. "Aloe vera." In: Coates PM, Betz JM, Blackman MR, et al., eds. Encyclopedia of Dietary Supplements. 2nd ed. New York, NY: Informa Healthcare; 2010:7-14.

26. National Library of Medicine. "Drugs and Lactation Database (LactMed): Aloe." 2020.