Oil, lotion, butter — shelved together, priced similarly, and doing genuinely different things. Choosing badly is why some people conclude their skin doesn't respond to anything. Here's the difference that matters.
The one distinction to understand
Skin loses water constantly. You can help it two ways: add water, or stop water leaving. Most products do one well and the other poorly.
Lotion is mostly water held in an emulsion. It adds moisture. It absorbs fast, feels light, and on very dry skin it can wear off before it's done much.
Body butter is largely solid fats — shea, cocoa — with little or no water. It doesn't add moisture so much as seal it. Rich, slow to absorb, excellent on genuinely cracked skin and heavy on anyone else.
Body oil contains no water either, but the good ones absorb rather than sit. A dry oil slows water loss while feeling like almost nothing.
So which do I need?
Dehydrated and tight but not flaky — lotion, or oil on damp skin.
Genuinely dry, flaking, rough patches — butter on the worst areas, or lotion followed by oil.
Normal skin that just looks dull — oil. This is the most common case and the one where butter is overkill.
Sensitive or breakout-prone on the body — lighter is safer. A dry oil built on squalane tends to sit better than a heavy occlusive.
Why oil and lotion together beats either alone
The lotion supplies water; the oil keeps it there. Lotion first, oil while skin is still slightly damp. It's the same logic as applying oil straight out of the shower — you're always trying to trap water that's already present rather than hoping oil alone will hydrate. More on the timing in after-shower body oil.
What about greasiness?
Greasy is a formulation outcome, not an inevitability of oils. Heavy botanical oils sit on the surface for a long time. Lightweight esters and squalane absorb in seconds. Our Meu Brilho is a dry oil for exactly this reason — squalane, meadowfoam and sweet almond, with a finish that's set and dry within a minute. The full explanation is in what makes a body oil non-greasy.
The glow question
Only one of the three does anything visual. Lotions and butters condition; a shimmer oil also adds light, which is a different purpose entirely — for shoulders and collarbones before an event rather than for elbows in July. If you want both jobs from one product, that's what an illuminating dry oil is for.
The short version
Lotion adds water. Butter seals heavily. Oil seals lightly and can add glow. Most people are best served by lotion when skin is dry and oil when it's dull — and by both, in that order, when it's neither behaving. Everything body-side is in The Body Edit.