Which plant is it from?

The INCI name does not say, which is a real limit on what an ingredient list can tell you here. Two products carrying the same entry may have started from different oils.

Is hydrogenation bad?

It is a trade. It buys solidity and stability by removing the double bonds, and it costs whatever the unsaturated acids and the more delicate minor components were contributing. For a balm that has to stay stable, that is usually the right trade.

What about trans fats?

That argument comes from food, where the material is eaten. Whether it means anything for an oil applied to skin is not something we have verified, so we neither raise it as an alarm nor dismiss it.

Far less readily than the oil it was made from. Rancidity starts at double bonds, and hydrogenation is the removal of those, which is much of why the material is used.

Is it safe during pregnancy?

We have left this unknown rather than guess. It is a structuring lipid rather than an active, but a pregnancy question about a specific product is one for a clinician.

Hydrogenated Vegetable Oil — Ingredient Guide

How it works

Hydrogenated vegetable oil is a plant oil whose double bonds have been reacted with hydrogen, saturating them. Two things change at once. The material becomes solid or semi-solid at room temperature, because saturated chains pack together far more readily than kinked unsaturated ones. And it becomes much more stable, because the double bonds oxidation needed are no longer there.

In a formula it behaves as a soft structuring lipid: it thickens an oil phase, gives a balm or a stick body, and leaves a smooth, non-greasy feel rather than the slip of a liquid oil. Its most notable property from a reader's point of view is what the name withholds — the INCI term does not say which plant the oil started as, so one entry can cover materials that began quite differently.

The evidence

The chemistry is settled, and the same trade appears elsewhere in this corpus: squalane is the hydrogenated form of a lipid that is unstable in air, and it is used precisely because hydrogenation removed the instability. The cost is symmetrical. Whatever the original oil offered through its unsaturated acids and its more delicate minor components is reduced or gone, so a hydrogenated oil is chosen for behaviour rather than for botanical character.

The question people usually bring to the word belongs to food. Trans isomers formed during partial hydrogenation are a dietary concern, argued about because the material is eaten; whether that has any bearing on an oil applied to skin is not something we have verified, and this page will not assert it in either direction. Nothing here treats a skin condition.

Suitability

A structuring emollient rather than an active; no skin type needs it
Useful where a stable, non-greasy solid lipid is wanted
Anyone choosing oils for their botanical character will not want it
Found in balms, sticks, rich creams and colour cosmetics

Concentration

Not published, and the level follows the texture rather than any effect: how firm the product has to be decides how much goes in. There is no effective concentration to quote because there is no effect being dosed. No comedogenicity rating is given either, and here the reason is sharper than usual — the name covers a family of materials from different feedstocks, so a single rating could not describe them all.

Conflicts & combinations

No incompatibilities. It sits in the oil phase and works with the waxes and butters around it. The only practical note is the one that applies to any film-forming lipid: a product built on it comes off with an oil-based or surfactant cleanser rather than being rinsed away, and whatever is layered over it is layered over a film.