Why Most Supplements Don't Absorb (and How Liposomes Fix It)

Most oral supplements deliver far less than the label suggests. A nutrient has to survive stomach acid, dissolve well enough to be taken up, cross the intestinal wall, and then run the gauntlet of first-pass metabolism in the liver. At every step some of the dose is lost, and liposomal delivery is designed to protect the nutrient through this journey so more of it may arrive intact.

What oral bioavailability really means

Oral bioavailability is the fraction of a nutrient you swallow that actually reaches systemic circulation in an active form. A supplement can be high-dose on paper yet low-bioavailability in practice, because absorption — not the number printed on the bottle — determines how much your body can use. Two products with identical milligram counts can behave very differently once the delivery form is taken into account. This is why comparing labels by dose alone can be misleading: the more meaningful question is how much of that dose survives digestion and crosses into the blood. For fragile or poorly soluble compounds, that surviving fraction can be a small share of what you swallowed, which is exactly the gap delivery technology tries to close.

Four reasons standard supplements underdeliver

1. Acid and enzymes. The stomach's acidic, enzyme-rich environment can degrade sensitive compounds before they are ever absorbed. A phospholipid bilayer around the nutrient may protect the payload from enzymatic decomposition during absorption and transport (PMC11076820).
2. Poor solubility. Fat-loving compounds like curcumin dissolve readily in solvents such as DMSO, ethanol, or acetone but barely dissolve in water, so little is available to absorb — a classic cause of low bioavailability (PMC6070829). CoQ10 is similar: a fat-soluble, light-unstable molecule with very low water solubility and correspondingly low bioavailability (PMC12191517).
3. Saturable uptake. The intestinal wall only admits so much of a molecule at a time. Vitamin C, for example, uses saturable transporters, and plasma tends to saturate around 70 µmol/L, so excess unencapsulated vitamin C is simply excreted (PMC10975307).
4. First-pass metabolism. Much of what is absorbed passes through the liver first, where it can be chemically altered before reaching the rest of the body — reducing the amount that circulates in active form.

How a phospholipid shell changes the math

A liposome is one or more phospholipid bilayers enclosing an aqueous core. Phospholipids are amphiphilic — a water-loving head and water-fearing tails — so they self-assemble in water into vesicles that can carry both water-soluble and fat-soluble cargo (PMC10180326). That shell shields the nutrient from acid and enzymes, keeps poorly soluble compounds dispersible, and presents the payload to intestinal cells in a form they may take up more readily. Just as important, the bilayer gives slow, controlled release rather than dumping the entire dose into the stomach at once, so the nutrient is metered out where it can actually be absorbed (PMC11076820).

Bypassing the liver's first pass

Some formulations route their cargo through intestinal lymphatic transport. Lipids assembled as 2-monoacylglycerol are packaged into chylomicrons that travel via the lymph, which partly bypasses liver first-pass metabolism and may increase oral absorption (PMC11164214). Liposomal phospholipids can also be hydrolyzed to lysophospholipids that form mixed micelles with bile salts — a natural digestive pathway — and those mixed micelles promote intestinal absorption (PMC12466359). In other words, a well-designed liposome does not fight the gut; it borrows the same machinery the body already uses to absorb dietary fat.

The problem was never the nutrient. It was everything standing between the pill and your bloodstream.

What the vitamin C research shows

Vitamin C is a useful test case because its uptake is capped by saturable transporters. A randomized controlled trial found that liposomal delivery increased vitamin C absorption into plasma and into leukocytes compared with a non-liposomal form (PMID 39237620), and a separate comparison study reported enhanced bioavailability with the liposomal format (PMID 32901526). The takeaway is not that liposomes create more nutrient, but that they may help more of the dose survive the trip and get past the transporter bottleneck — so a larger share reaches the cells that use it rather than being lost to excretion.

Why size and uniformity feed into absorption

Delivery vesicles at the nanoscale are typically 100-200 nm, and smaller, more uniform particles tend to be absorbed better than large, variable ones. A surface charge (zeta potential) helps keep the vesicles from clumping, which supports both stability on the shelf and consistent behavior in the gut (PMC9781429, PMC10180326). This is one reason two products can share the same nutrient and dose yet differ in how much actually gets absorbed.

Frequently asked questions

Why do supplements have low bioavailability?

Because nutrients face stomach acid, digestive enzymes, poor water-solubility, saturable intestinal uptake, and liver first-pass metabolism — each step removes part of the dose before it reaches circulation.

Does a higher dose fix poor absorption?

Not reliably. Dose is how much is in the pill; bioavailability is how much your body absorbs. With saturable nutrients like vitamin C, excess is simply excreted, so improving the delivery form often does more than raising the dose.

How do liposomes improve absorption?

They may protect the nutrient from digestion, keep poorly soluble compounds dispersible, and promote uptake through intestinal cells and lymphatic transport that partly bypasses the liver's first pass.

Is liposomal always better?

It helps most for nutrients that are fragile in the gut or poorly soluble, such as vitamin C, curcumin, and CoQ10. For a nutrient that already absorbs well, the added benefit may be smaller, so the value depends on the specific compound.

Sources: PMC10180326; PMC11076820; PMC12466359; PMC11164214; PMC10975307; PMC6070829; PMC12191517; PMC9781429; PMID 39237620; PMID 32901526. Educational content about nutrient delivery; not medical advice.