From the article by (Lodén, 2005) suggested by @Wayfaring Stranger, the answer seems to be Partly, but not too conclusive (emphasis mine everywhere):
Moisturizers are recommended for use in normal skin to
prevent the appearance of dryness.131,132 Despite their widespread
use, only a few studies have focused on their influence on
the permeability barrier. Treatment with moisturizers may well
influence the barrier properties of normal skin. Treatments usually increase skin hydration, but no increase in TEWL [trans-epidermal water loss] tends
to follow. However, changes in skin reactivity have been
noted. A lipid-rich cream without any humectant had no
influence on TEWL, but skin susceptibility to SLS [sodium lauryl sulphate] irritation was
increased compared to untreated skin. Increased skin
reactivity was also found in a long-term study using benzyl
nicotinate as a marker for permeability, where the time to
maximum response was shorter for the cream-treated area
compared to the untreated. In addition, the time to induce
vasodilatation was shorter for the lipid-rich cream than for
a moisturizer containing 5% urea. Increased sensitivity to
nickel was also found when nickel-sensitive humans treated
their skin with moisturizers without humectant, compared to
treatment with moisturizer with humectant.
On the other hand, areas treated with the glycerol-containing
cream showed less reactivity to nickel than those treated with a
cream without any humectant. Furthermore, repeated applications
of urea-containing moisturizers have been found to
reduce TEWL and make skin less susceptible to SLS-induced
irritation. An increased resistance to SLS-induced
irritation and xerosis has also been found after treatment with
AHA. [...] Moreover, another humectant,
dexpanthenol, has been reported to decrease TEWL after 7 days
treatment.
Thus, long-term side effects range from non-existent to altered sensitivity to certain chemical compounds, which is not necessarily a negative effect.
As for adverse effects, the author has this to say:
Compared to traditional drugs used by dermatologists,
moisturizers are rarely associated with health hazards, although
they may be used on large body areas over a large part of the
human life span [...] However, intoxication has occurred. For example, topical
treatment with salicylic acid in children with lamellar ichthyosis
and treatment with high concentrations of propylene glycol in
burn patients have resulted in poisoning. Moreover, some
products, particularly Chinese herbal creams have been shown
repeatedly to be adulterated with corticosteroids, which may
cause serious side effects.
The article concludes with:
Clear evidence exists that moisturizers are important in the treatment of different dry skin conditions. Furthermore, moisturizers prevent the appearance of dryness, and some formulations may also improve skin barrier function and make skin less prone to eczema. The key to future moisturizer therapy will be to tailor the treatment to the distinct abnormalities that manifest themselves with the generally recognized symptoms of dryness. Ranking the efficacy will be facilitated by an increased knowledge of their interaction with the skin. So far, the links between the abnormality and the composition of the moisturizer remain largely unexplored. Therefore, it may be a matter of trial and error to find the most suitable formulation for an individual.
All said, the article claims that the long-term effects are largely dependent on the actual skin condition and the chemical content of the applied product. Short-term effects are evident and undeniable. Prolonged use is not commonly associated with adverse effects. Consultations with specialist dermatologists are recommended to determine which products have the most beneficial effect on the patients, as well as dosage and application.
Source (and references therein):
Lodén, M. (2005) The clinical benefit of moisturizers, Journal of the European Academy of Dermatology and Venereology, 19-6, p. 672–-688. doi: 10.1111/j.1468-3083.2005.01326.x
