Stearic acid side effects, health benefit and safety
February 1 2017

Stearic acid is a long-chain saturated fatty acid. Stearic acid is one of the useful types of saturated fatty acids that come from many animal and vegetable fats and oils.  Its name comes from the Greek word stéar which means tallow. The term stearate is applied to the salts and esters of stearic acid. It's very stable in storage and during frying. A relatively large percentage of stearic acid consumed is converted to oleic acid (a monounsaturated fat).

Stearic acid side effects
I am not aware of any human studies that been published in the medical literature as of 2017 that have shown reasonable amounts of stearic acid ingestion to have side effects, be toxic, or unsafe.

Lipids. 2005. Influence of stearic acid on hemostatic risk factors in humans. Stearic acid has been claimed to be prothrombotic. Elevated plasma factor VII coagulant activity (FVIIc) may raise the risk of coronary thrombosis in the event of plaque rupture. Fibrinogen, an acute-phase protein, is necessary for normal blood clotting; however, elevated levels of fibrinogen increase the risk of coronary heart disease (CHD). Here I report the results of three controlled, human dietary intervention studies, which used a randomized crossover design to investigate the hemostatic effects of stearic acid-rich test diets in healthy young men. A diet high in stearic acid (shea butter) resulted in a 13% lower fasting plasma FVIIc than a high palmitic acid diet, and was 18% lower than a diet high in myristic and lauric acids after 3 wk of intervention. The stearic acid-rich test fat increased plasma fibrinogen concentrations slightly compared with the myristic-lauric acid diet. When investigating the acute effects of fatty meals, those high in stearic acid (synthesized test fat) resulted in a smaller postprandial increase in FVII than those high in trans and oleic FA, indicating a smaller increase in activated FVII after ingesting stearic acid compared with fats high in monounsaturated FA, probably caused by lower postprandial lipemia. Thus, the present investigations did not find dietary stearic acid to be more thrombogenic, in either fasting effects compared with other long-chain FA, or in acute effects compared with dietary unsaturated FA, including trans monounsaturated FA.

Use in dietary supplements
Some nutritional supplements have magnesium stearate which helps with the production of these natural pills.

Stearic acid in foods
Stearic acid is used to form margarines, shortenings, spreads, and as a cream base for baked products. It is found naturally in meat, dairy products, butter, and chocolate.

Stearic acid and cholesterol
Even though it is a saturated fat, studies have suggested that it has little effect on blood cholesterol levels, because such a high proportion is converted to oleic acid.

Stearic acid in chocolate, cocoa, cacao
Stearic acid is sound in some plant foods like cacao, cocoa, chocolate.

Stearic acid and cholesterol
Stearic acid does not seem to raise serum cholesterol concentrations. Stearic acid does not seem to raise low-density-lipoprotein cholesterol relative to oleic acid, which is known to be neutral in its effects on cholesterol concentrations. In contrast, palmitic acid, another long-chain saturated fatty acid, raises cholesterol concentrations. For this reason, fats rich in stearic acid might be used in place of those high in palmitic acid in cholesterol-lowering diets.