Splenda’s original yellow packets contain just three ingredients: dextrose, maltodextrin, and sucralose. Sucralose is the zero-calorie artificial sweetener, but it makes up only a tiny fraction of what’s in the packet. The bulk of each packet is dextrose and maltodextrin, two carbohydrate-based fillers that give Splenda its sugar-like volume and texture.
The Three Ingredients in a Splenda Packet
Dextrose is a simple sugar derived from corn. Maltodextrin is a starch-based carbohydrate, also typically made from corn. These two ingredients are listed first and second on the label because they make up the vast majority of the packet by weight. They’re called bulking agents: their job is to give you something you can actually scoop and pour, since pure sucralose is so intensely sweet that you’d only need a near-invisible speck to match the sweetness of a teaspoon of sugar.
Sucralose itself is the signature ingredient. It’s made by chemically modifying regular table sugar (sucrose), replacing three oxygen-hydrogen groups on the sugar molecule with chlorine atoms. The result is a compound about 600 times sweeter than sugar that your body largely doesn’t recognize as food. Its molecular formula is C₁₂H₁₉Cl₃O₈. Because so little sucralose is needed per packet, the calorie content rounds to zero on the label, though the dextrose and maltodextrin do contribute a small number of calories (roughly 3 per packet).
Liquid Splenda Has a Different Formula
The liquid version of Splenda skips the bulking agents entirely. Its ingredient list is water, sucralose, malic acid (for tartness and stability), sodium benzoate, and potassium sorbate. The last two are common preservatives found in many bottled beverages and condiments. Because there’s no dextrose or maltodextrin, liquid Splenda contains no carbohydrates at all, which makes it a meaningfully different product for anyone watching their blood sugar.
Why the Fillers Matter for Blood Sugar
Maltodextrin has a high glycemic index, meaning your body breaks it down into glucose quickly. Research confirms that maltodextrin, even in products marketed as diabetic-friendly, can contribute to blood sugar spikes in a dose-dependent way. Dextrose is pure glucose. The amounts in a single Splenda packet are small, but if you’re using several packets a day, the carbohydrates add up. For most people this is negligible. For someone closely managing diabetes or following a strict ketogenic diet, it’s worth knowing that Splenda packets aren’t truly zero-carb despite their labeling.
What Happens to Sucralose in Your Body
Most sucralose passes through your digestive tract without being absorbed. Studies tracking radiolabeled sucralose in humans found that roughly 65 to 95 percent leaves the body unchanged in feces. The portion that is absorbed gets excreted through urine, mostly within a few days. However, in at least two of eight subjects in one study, about 12 percent of the ingested dose had not been excreted five days after a single serving, which raises questions about whether sucralose or its breakdown products can linger in the body longer than originally thought.
There’s also some evidence that sucralose may be partially metabolized in the gut, contrary to early claims that it passes through completely unchanged. Researchers analyzing fecal samples after sucralose consumption found at least two distinct metabolic byproducts, though their biological effects haven’t been fully characterized.
The Chlorine Question
The three chlorine atoms in each sucralose molecule are a frequent concern. Sucralose is technically classified as an organochlorine compound, a chemical family that includes some notorious industrial pollutants. But the chlorine in sucralose is tightly bonded to the sugar backbone, and the molecule behaves very differently from something like a pesticide. The chlorine atoms are what prevent your body from breaking sucralose down for energy, which is the whole reason it has no calories. Since most of the compound exits your body intact, the chlorine largely goes with it.
That said, heating changes the equation. The German Federal Institute for Risk Assessment found that when sucralose is heated above 120°C (about 248°F), it begins to break down and release chlorinated organic compounds with potentially harmful properties. The institute recommends not baking, frying, or roasting foods that contain sucralose, and instead adding it after cooking. Standard baking temperatures easily exceed this threshold, which is worth knowing if you use Splenda in cookies or cakes.
Gut Bacteria Effects
Animal studies initially raised alarms about sucralose altering gut bacteria, but human clinical trials have been less dramatic. A study giving healthy subjects 780 mg of sucralose daily (a high dose, split across three servings) for one week found no changes to gut microbiome composition at the phylum level. Another two-week trial using 20 percent of the acceptable daily intake also found no significant shifts in gut bacteria or short-chain fatty acid production. Long-term studies in humans suggest some correlation between habitual sweetener use and differences in certain bacterial groups, but short-term controlled trials at normal intake levels haven’t confirmed a clear cause-and-effect relationship.
How Much Is Considered Safe
The FDA sets the acceptable daily intake for sucralose at 5 milligrams per kilogram of body weight per day. For a 150-pound person, that works out to about 340 milligrams daily. Each Splenda packet contains roughly 12 milligrams of sucralose, so you’d need to use around 28 packets in a single day to reach that limit. Most people consume far less than this, which is why regulatory agencies in over 80 countries have approved sucralose as safe for general use.