Users have generally positive feedback about the TRIPLE COLLAGEN SERUM 4.0 by medicube. Many users highlight its hydrating properties, noting that it provides deep hydration and leaves the skin feeling plump and firm. Several reviews mention that it is suitable for dry skin and helps improve skin texture and elasticity. Users also appreciate its lightweight texture and pleasant fragrance. However, some users point out that the product quantity is small relative to its price, and a few mention that it can feel a bit heavy or sticky, especially for those with oily skin. Additionally, there are concerns about the presence of alcohol and PEG in the formula, which some users find unsettling despite not experiencing major irritation.

Here are some specific points from the reviews:

Overall, the serum is well-received for its hydrating benefits, though users suggest being mindful of the quantity and potential stickiness, especially for those with oily skin.