Aloe vera is a succulent plant, formally known as Aloe barbadensis Miller, whose thick, fleshy leaves produce a clear gel used for skin care, wound healing, and a growing list of health applications. The plant contains over 200 bioactive compounds packed into that inner gel, which is roughly 99% water with a potent 0.5 to 1% of active solids including vitamins, minerals, enzymes, and sugars. It’s one of the most widely used medicinal plants in the world, appearing in everything from sunburn creams to dietary supplements.
What’s Inside the Leaf
An aloe vera leaf has two distinct parts that matter, and confusing them is a common source of problems. The inner clear gel is the part most people are familiar with. It’s the translucent, slippery substance you see when you slice a leaf open. This gel contains the plant’s beneficial compounds: vitamins B1, B2, B6, C, folic acid, and beta-carotene, along with minerals like calcium, magnesium, zinc, iron, potassium, and chromium. It also contains a range of enzymes that act as antioxidants, helping to neutralize damaging molecules in the body.
The star compound in aloe gel is acemannan, a sugar molecule (polysaccharide) that researchers have identified as the primary active ingredient behind many of the plant’s health effects. Acemannan supports immune function and plays a central role in aloe’s wound-healing abilities. Quality standards from the International Aloe Science Council require a minimum of 5% acemannan content by dry weight in certified products.
The second part of the leaf is the latex, a yellow substance found just beneath the outer skin. This is where a compound called aloin lives, and it behaves very differently from the gel. Aloin is a potent laxative, and the distinction between gel and latex is critical for anyone using aloe internally.
How Aloe Vera Heals Skin
Aloe vera’s reputation as a skin healer isn’t just folk wisdom. The gel works through a specific mechanism: a compound called glucomannan binds to receptors on fibroblasts, the cells responsible for building connective tissue. This stimulates those cells to multiply and ramp up collagen production. Aloe doesn’t just increase the amount of collagen in a wound. It actually changes collagen’s composition and increases the cross-linking between collagen fibers, making the repaired tissue stronger.
Applied topically, aloe gel also keeps wounds moist. This matters because a moist wound environment allows skin cells and growth factors to migrate across the damaged area more efficiently than a dry, scabbed surface. The gel essentially acts as a biological wound dressing. Studies have shown effective wound healing with concentrations ranging from 1 to 100 mg per kilogram of body weight.
For chronic skin conditions, the results can be striking. In a double-blind, placebo-controlled trial of psoriasis patients, a cream containing just 0.5% aloe vera extract cleared psoriatic plaques in 83.3% of patients over four weeks, compared to 6.6% in the placebo group. Patients applied the cream three times daily, five days a week, with no toxic side effects reported. The natural sugars in aloe gel also bind water to the skin’s surface, providing a humectant effect that supports the skin barrier and helps maintain hydration.
Digestive and Metabolic Effects
Taken orally, aloe vera gel (not latex) has shown measurable benefits for irritable bowel syndrome. A meta-analysis of three randomized controlled trials found that aloe vera significantly improved IBS symptom scores compared to placebo, with patients about 69% more likely to see improvement. The doses used in these trials ranged from aloe vera juice taken multiple times daily to concentrated extract tablets taken twice a day. One important caveat: the benefits held up in short-term treatment of about one month, but longer treatment beyond three months did not show a statistically significant advantage over placebo.
Aloe vera’s effects on blood sugar have also drawn attention. A meta-analysis of studies in people with prediabetes and diabetes found that oral aloe vera reduced fasting blood glucose by an average of 46.6 mg/dL and lowered HbA1c (a marker of long-term blood sugar control) by 1.05%. The effect was especially pronounced in people with higher baseline blood sugar: those starting above 200 mg/dL saw an average reduction of nearly 110 mg/dL, while those below 200 mg/dL saw a modest drop of about 7.6 mg/dL.
Gel, Latex, and Whole Leaf: Why It Matters
The difference between aloe vera products comes down to which part of the leaf is used. Inner leaf gel products contain primarily the clear gel, with very low levels of aloin. Whole leaf extracts include material from the entire leaf, meaning they can contain significantly more aloin. Chemical analysis has shown that unfiltered whole leaf extracts can contain 100 times more aloin than filtered, decolorized versions (8 mg/g versus 0.08 mg/g).
This distinction has real safety implications. The International Aloe Science Council caps allowable aloin content at 10 parts per million for oral products, a threshold specifically set to prevent laxative effects. When shopping for aloe products intended for internal use, look for IASC certification or labels specifying “inner leaf” or “decolorized” processing.
Safety Risks of Aloe Latex
While aloe gel is broadly considered safe for both topical and oral use, aloe latex is a different story. The FDA ruled in 2002 that aloe latex is not generally recognized as safe and effective as an over-the-counter laxative. Prolonged use of aloe latex can cause diarrhea, abdominal pain, dangerous drops in potassium levels, and a condition where the colon loses muscle tone and becomes dilated. Taking as little as 1 gram per day of aloe latex for several days can cause kidney damage.
Children under 12 should not take aloe latex or whole leaf extract orally. The same applies to anyone who is pregnant or breastfeeding. Aloe latex also interacts with stimulant laxatives, potentially causing severe dehydration. Ingestion of improperly processed aloe preparations has been associated with phototoxicity (increased sensitivity to sunlight) and allergic reactions, though these are less common with pure inner leaf gel products.
Choosing a Quality Product
The aloe vera market ranges from raw leaves at the grocery store to highly processed supplements, and quality varies enormously. For topical use, products listing aloe vera as the first ingredient (rather than water with a small percentage of aloe) deliver the most benefit. For internal use, certified products should meet the IASC standard of at least 0.46% solids in single-strength inner leaf juice, contain detectable levels of malic acid and glucose (markers of genuine aloe content), and keep aloin below 10 ppm. Products that list maltodextrin without declaring it on the label are considered adulterated under IASC standards, as maltodextrin is sometimes used to bulk up products and inflate the apparent aloe content.
If you’re using a fresh leaf, you can scoop out the clear inner gel while avoiding the yellowish layer just under the rind. That yellow layer is the latex. Rinsing the gel under water before use helps remove any residual latex that may have seeped onto the surface during cutting.