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11 Proven Benefits of Aloe Vera + Side Effects

Written by Helen Quach, BS (Biochemistry) | Last updated:
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology) | Written by Helen Quach, BS (Biochemistry) | Last updated:

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Aloe vera has been used as a household cure for many ailments. It is anti-inflammatory, antimicrobial, and anticancer. It also improves skin health, protects against diabetes, and eases heartburn.

What is Aloe Vera?

Aloe vera (Aloe barbadensis miller) is a shrubby green plant. It grows in the dry regions of America, Africa, Asia, and Europe. Many people have been using aloe for its beauty, health, and medicinal effects for centuries [1].

Forms of Aloe Vera

  • Gel: You can apply aloe vera gel onto the skin to help reduce inflammation, clear skin, and heal wounds [2].
  • Juice and Supplements (capsules): You can take aloe vera orally via supplements or juice to stop constipation, boost the immune system, or reduce diabetes symptoms [1].


Aloe vera leaves have three layers [1, 3, 4]:

  • Rind (outer layer) – It protects the plant, transports substances (water and starch), and produces proteins and carbs.
  • Latex (middle) – It contains glycosides (sugars bound to another compound) and anthraquinones (phenolic compounds). Barbaloin/aloin, isobarbaloin, and emodin are the main active compounds.
  • Gel (inside) – It contains water, sugar, amino acids, fat, and vitamins. Glucomannan, salicylic acid, and phytosterols are the main active compounds.

The latex and gel contain most of aloe vera’s active compounds. Aloe vera’s vitamins and anthraquinones have antioxidant properties. Its enzymes, glycoproteins, fatty acids, and hormone are anti-inflammatory [1].

Health Benefits

1) Is Anti-Inflammatory

In a study of 40 volunteers, topical aloe vera gel application on their backs reduced UV-ray induced inflammation. Aloe vera gel was better at reducing inflammation and redness than hydrocortisone cream [5].

In human colon cells, aloe vera gel dose-dependently inhibited inflammation. Aloe vera has potential in treating inflammatory bowel disease [6].

Aloe vera gel also suppressed inflammatory markers in human immune cells [7].

In mice, topical aloe vera application on their ears also reduced inflammation (that was caused by an irritant) [8].

Aloe vera’s anti-inflammatory effects come from its ability to reduce PGE2 production and stop the cyclooxygenase pathway [1].

Aloe vera also suppresses other inflammatory markers like TNF-a and IL-1B [9].

It contains C-glucosyl chrome, an anti-inflammatory compound [10].

2) Is Antimicrobial

In an of 390 people, aloe vera mouthwash was as effective as antibacterial chemicals in removing plaque. After thirty days, the aloe vera group also had healthier gums and less plaque compared to the controls [11].

Herpes simplex is a virus that can cause cold sores and other diseases in the mouth. Aloe vera gel can kill herpes simplex virus without being toxic to other cells [12].

Aloin (extracted from aloe vera) inactivated several viruses (influenza, herpes simplex, and varicella zoster) [13].

Water and alcohol aloe vera extracts can inhibit gram-positive and gram-negative bacteria, although the alcoholic extract is more efficient. The extracts inhibited Enterococcus bovis, Staphylococcus aureus, E. coli, Proteus vulgaris, P. mirabilis, Pseudomonas aeruginosa, Morganella morganii, and Klebsiella pneumoniae [14].

Purified aloe vera protein also inhibited fungal growth (Candida paraprilosis, C. krusei, and C. albicans) [15].

Aloe vera contains antimicrobial compounds (phenols, sulfur, salicylic acid, lupeol, urea nitrogen, and cinnamonic acid), which inhibit viruses, bacteria, and fungi [1].

Aloe vera breaks bacterial cells to stop their growth [16].

3) Boosts the Immune System

Aloe vera contains many antioxidants – Vitamin C and E, flavonoids, tannins, and carotenoids. By stopping oxidative damage, the antioxidants can protect the immune system [17].

In guinea pigs, alprogen (an aloe vera constituent), inhibited mast cell formation. Mast cells are white blood cells that may cause inflammation and hypersensitivity or allergic reactions. When alprogen inhibited mast cell formation, it prevented histamine and leukotriene release and prevented allergic reactions [18].

Aloe vera extract also caused mice’s white blood cells to release interleukin-1 and tumor necrosis factor, which stimulates the immune system [19].

Aloeride, a sugar from aloe vera juice, activates white blood cells (macrophages), which also stimulates immune system function [20].

4) May Be Anti-Cancer

Various aloe vera polyphenols stopped cancer growth in human cells. Both aloe-emodin and emodin inhibited skin cancer cell growth. Also, combining aloe-emodin with chemotherapy drugs (5-fluorouracil, abiplastin, and adriablastin) enhanced their effects [21].

Polysaccharides from aloe gel extract prevent carcinogens from forming [22, 1].

Various aloe vera constituents (emodin, aloin, and anthracene) inactivate cancer molecular pathways [16].

5) Improves Diabetes Symptoms

In a study of 30 type 2 diabetic patients (with high cholesterol), aloe gel capsule supplementation helped control diabetes. Taking 300 mg of aloe gel capsules twice daily for two months lowered blood sugar, total cholesterol, and LDL (bad cholesterol) levels. It also lowered HBA1c, a long-term measure of blood sugar [23].

A review showed that diabetic patients had the most improvement in blood sugar after taking aloe compared to healthy patients [24].

In human cells, an aloe vera compound (aloe-emodin glycosides) increased glucose uptake and glycogen synthesis. This reduces glucose levels and helps stop insulin resistance [25].

6) Heals Wounds

In a study of 30 burn patients, aloe vera gel helped treat burn wounds better than Nitrofurazone, an antibacterial ointment used to treat wounds. The aloe gel helped regrow new skin faster than the antibiotic ointment in patients with second-degree burns [26].

In a study of 18 facial scarring patients, topical aloe vera gel helped heal skin more quickly. The treatment also reduced pain from their wounds better than antibacterial ointment [27].

However, there are conflicting results from other studies. In women with surgical scars, applying aloe vera gel on their skin significantly delayed wound healing compared to a standard ointment [28].

Aloe vera’s constituents, glucomannan (sugar) and gibberellin (a growth hormone), interact with growth factors, which stimulates skin cell activity and growth. This is how topical and oral aloe vera stimulates collagen formation and heal wounds [1].

Additionally, aloe vera improved collagen composition, which helps heal wounds faster [29].

7) Improves Skin Health

In a study of 30 participants with dry hands, aloe vera gel (by wearing a glove for 8 hours a day) improved dry skin after about 4 days. There was a significant improvement after 10 days in skin strength, wrinkling, and reddening [30].

In a study of 41 psoriasis patients, aloe vera gel decreased redness, peeling, and pain by 72.5%. However, the placebo was more effective at reducing psoriasis symptoms (82.5%) [31].

Aloe vera gel application on rat skin increased the formation of metallothionein, an antioxidant protein. The protein stops UV ray-caused oxidative damage, prevents antioxidant suppression, and reduced immunosuppressive cytokine (IL-10) release [32].

Sugars from aloe vera help moisturize the skin by stimulating skin cells. The increase in collagen and elastin also soften the skin, makes it more elastic, and reduces wrinkles [30, 1].

8) Acts as a Laxative

Aloe vera helps relieve constipation. In a study of 35 chronic constipation patients, aloe vera and fiber pills helped reduce constipation more than the control pills. The patients experienced more frequent bowel movements, softer stools, and took laxatives less often [33].

However, in rats, aloe-emodin extracted from aloe vera had a strong laxative effect and even induced diarrhea [34].

Phenolic compounds from aloe vera latex are responsible for its laxative effects. They stimulate the intestine, increase intestinal water, and stimulates contractions (peristalsis) [34].

9) Aloe Vera Gel Treats Canker Sores

In a study of 40 patients with canker sores (minor aphthous lesions), aloe vera gel decreased healing time. It reduced pain and wound size [35].

In another study of 90 patients, aloe vera gel fully healed 76% of the patients’ canker sores. It was especially efficient at decreasing ulcer size, redness, and oozing [36].

10) Eases Heartburn

In a pilot study of 79 acid reflux patients, aloe vera was effective in relieving heartburn and acid reflux symptoms [37].

Compared to the group who received Omeprazole (a commonly prescribed heartburn medicine), the aloe vera group also had reduced heartburn, gas, vomiting, nausea, gas, and other symptoms. The aloe vera was well tolerated and had few adverse effects [37].

11) Protects Hair

UV radiation can cause hair to become dull, turn rough, and break easily. Aloe juice treatment on hair samples showed protective effects against UV ray damage [38].

Although aloe vera juice can protect all types of hair, it is more effective at keeping colored hair, then grey and black hair, shiny and smooth [38].

Limitation & Caveats

Because there are not many human trials available, caution should be taken while using aloe vera for its health benefits.

Side Effects & Precautions

Common Side Effects [4]:

  • Skin rashes
  • Burning and stinging
  • Diarrhea
  • Vomiting
  • Stomach cramps
  • Constipation

In various case studies, high oral doses of aloe vera caused kidney failure, hepatitis, liver dysfunction, and even hyperthyroidism [4].

Prolonged oral supplementation of aloe vera can cause potassium deficiency. This can eventually lead to heart problems [39].

High doses of aloe vera decreased brain activity in mice. After 90 days, it also damaged sperm, decreased red blood cell count, and increased cell death [40].

Two years of aloe vera leaf extract administration in drinking water caused the rats to develop tumors in their intestines. They had an increased risk for colon cancer [41].


People who are allergic to Liliaceae plants (onions, garlic, tulips, etc.) should avoid using aloe vera [39].

Pregnant women are also advised to not take aloe vera. It can have toxic effects on their embryo and fetus. It may also cause contractions [4, 1].

People with heart or kidney problems should be careful taking aloe vera as it can create an imbalance in the body’s electrolytes and cause potassium deficiency [4].

Drug Interactions

Aloe vera may have antiplatelet activity, meaning that it can cause blood thinning. In one case study, a woman taking aloe vera supplements experienced severe bleeding after oral surgery. Aloe vera interacted with sevoflurane to increase bleeding. However, no other studies have shown these effects [42].

Gene Interactions

  • Aloe vera gel increased expression (production) of GLUT-4, a protein needed to get glucose into cells (in mice) [43, 44].
  • Processed aloe vera gel also reduces the production of SREBP-1a, FAS, and GPAT; genes known to have an effect on fat synthesis (in mice) [4].
  • Sugars from aloe vera gel induce MMP-3 and TIMP-2 gene production in rats. This helps with wound repair and collagen formation [45].



Topically, aloe vera can be applied liberally on the skin to prevent dryness, soften skin, and reduce wrinkles [39].

When using to treat constipation, 0.04 – 0.17 grams of dried aloe vera juice is recommended. Additionally, a combination of 150 mg dried juice, psyllium (50 mg), and celandine (300 mg) is a safe alternative [39].

People normally drink 5 – 15 mL of aloe vera juice twice daily to help treat diabetes [39].

Aloe vera should not be injected into the body [39].

User Reviews

  • “Makes a significant difference in excess scar tissue both inside and out of the body.”
  • “I have used it as a base for skincare, and for sunburn salve. Exceptionally good product.”
  • “Great for soothing the digestive system.”
  • “Very useful product for sensitive skin.”
  • “Great to bust open and put on sores, scrapes and so on but not great for pain. I had read that the aloe vera caps were supposed to help relieve pain, be good for your stomach and a bunch of other stuff. I didn’t see any of that.”

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About the Author

Helen Quach

BS (Biochemistry)

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