What is the fatty acid composition of beef tallow?
It depends on how the animal was fed, and the difference is measurable. In a two-sample laboratory comparison run at the University of Illinois, grass-fed tallow came out at 27.45% palmitic, 37.55% oleic and 17.45% stearic acid, with 50.4% total saturated, 46.3% monounsaturated and 1.9% polyunsaturated fat. The grain-fed sample from the same run was 27.7% palmitic, 30.9% oleic and 12.8% stearic, with 3.45% polyunsaturated fat. An unrelated 2025 measurement of commodity tallow reported 30.29% palmitic, 18.65% stearic, 28.80% oleic and 1.78% linoleic acid, which is close enough to treat the general shape as settled.
Is grass-fed tallow actually different from grain-fed tallow?
In the samples measured, yes, though not in the way people usually assume. Total saturated fat barely moved, 50.4% against 47.65%. What moved was underneath: the grass-fed sample carried 45% less total polyunsaturated fat, about a third more stearic acid, and 3.8% trans vaccenic acid against 10.8% in the grain-fed sample. This is one pair of samples rather than a survey, so read it as a documented difference rather than a specification for every jar.
Which skincare oil oxidises fastest?
Of the fats on this page, rose hip seed oil, on published relative rates. Huang and Ahn index oxidation speed against stearic acid at 1, putting oleic at 100, linoleic at 1,200 and linolenic at 2,500. Rose hip is roughly 45% linoleic and 22% alpha-linolenic, which weights out to about fifteen times the index of grass-fed tallow. Safflower follows at about thirteen times. Coconut oil is the most stable at roughly a third of tallow's index, because 92% of it carries no double bond at all. This describes how the oil keeps in its container. It is not a statement about anyone's skin.
Is jojoba oil really not an oil?
Not in the chemical sense. Jojoba is the only plant known to store wax esters rather than triacylglycerols in its seeds. The Cosmetic Ingredient Review panel describes jojoba esters as proper waxes with no triglyceride component, built from long chain C35 to C46 fatty acids and fatty alcohols joined by an ester bond. Any chart that hands jojoba a percent-oleic figure alongside olive oil has quietly substituted a different measurement, usually of the acids released after the wax esters are split apart in a laboratory.
Why does shea butter feel similar to tallow?
Because they arrive at a similar firmness from a similar place, using different acids. Tallow is heavy on palmitic acid, at roughly 27%, with stearic in the high teens. Shea reports almost no palmitic acid, about 3.5%, and loads stearic instead at nearly 39%. Both end up with a large saturated fraction of sixteen and eighteen carbon chains and a large oleic fraction, which is the combination that produces a solid-at-room-temperature butter rather than a pourable oil.
Does a fatty acid profile tell me how an oil will behave on my skin?
Less than most charts imply. Composition reliably predicts things about the fat itself: whether it is solid or liquid at room temperature, how quickly it oxidises in the jar, and how it behaves when warmed. It does not predict how a finished product feels on you, because that also depends on how the fat was processed, what else is in the formula, and your own skin. This tool deliberately stops at the first set of questions. It reaches no verdict on any product and makes no claim about any skin condition.
Why do published numbers for the same oil disagree?
Because natural fats are agricultural products. The shea study behind the figures here reports a standard deviation of 4.21 percentage points on oleic acid and 4.67 on stearic across the accessions it examined, and separate surveys put Ugandan and Chadian shea far higher in oleic acid than West African shea. Avocado oil is reported across a range of 31.8% to 69.6% oleic acid, which is more than a twofold spread in its largest component. A single tidy number for any of these is a convenience.
What is the oleic to linoleic ratio, and why is it here?
It is simply the oleic acid percentage divided by the linoleic acid percentage, and it is included because it is a number people go looking for and rarely find calculated. On the figures used here, grass-fed tallow sits at about 34 to 1, shea butter at about 8 to 1, and argan at about 1.4 to 1. It is a compact way of saying where a fat sits between the stable monounsaturated end and the reactive polyunsaturated end. It is a ratio of two measured numbers, not a grade.