Can hypothyroidism cause cellulite?
Clinical studies show that they can be used without any fear of altering thyroid hormone levels or triggering dysfunction on the gland. We discuss this with the expert
Concerns have been hovering around anti-cellulite products for a few years now about their alleged interference with thyroid functioning. The misgivings concern, in particular, anti-cellulite creams containing thyroid hormones, which are feared to alter the amounts of said hormones both in women with normal levels and in those taking hormone replacement therapy to treat hypothyroidism.
In fact, the most recent studies confirm that thyroid hormone-based anti-cellulite creams do not affect thyroid function in any way or alter physiological or orally taken amounts.
To shed light on this controversial subject, we asked Professor Enzo Berardesca, director of the Department of Inflammatory and Immunoinfectious Dermatology at the S. Maria and S. Gallicano Dermatological Institute in Rome, for clarification.
"First of all, it should be specified that anti-cellulite creams containing the thyroid hormone are to all intents and purposes drugs that should be distinguished, therefore, from cosmetics," the dermatologist explains. "It is no coincidence that they bear the label of self-medication on the packaging, as they are medical devices authorized by the Ministry of Health.
"Topical drugs (i.e., which are applied locally, ed.) treat cellulite, acting on the causes; cosmetics, on the other hand, treat skin imperfections by improving the appearance of the skin, including through the action of massage," - clarifies the expert. The difference between the two anti-cellulite products lies in the fact that drugs block the mechanism that establishes the formation of cellulite, namely primarily the accumulation of interstitial fluid in the dermis due to a slowdown in microcirculation. "This results in an inflammatory state that induces adipocytes (the fat cells of the subcutaneous fat) to increase in volume and number," - Berardesca continues.
Thus the skin begins to deform into the typical orange peel appearance. "In addition, in more advanced states of cellulite inflammation, collagen is produced in greater quantities to the point of creating nodules and fibrous tissue." We are in the case of so-called mattress skin. Here the anti-cellulite drug must prevent this, in particular dissolve fats, inhibit the excessive production of collagen, which is responsible (only for cellulite) for fibrous states, and reduce the formation of hyaluronic acid (in the treated areas), which instead contributes to fluid stagnation.
For the moment, the main pharmacological active ingredient capable of acting on the causes of cellulite is levothyroxine (not to be confused with tyrosine, which is an enzyme instead). For fairness of information, we specify that this is the same thyroid hormone that is taken orally, with the difference that in anti-cellulite creams it is included in the form of a sodium salt.
Are thyroid hormone-containing creams safe?
"Yes, because topically used levothyroxine acts only locally, not 'making time' to enter the capillaries in the active form. In other words, research from the University of Pisa* published in The Journal of Clinical Endocrinology & Metabolism found that the skin has its own metabolism that transforms thyroid hormone into an inactive molecule (i.e., one that does not interfere with thyroid mechanisms) once it has performed its function against the causes of cellulite. Thus, it is as if the skin acts as a "filter" against the body's absorption of thyroid hormone: meanwhile, however, it has acted in the dermis where it is needed."
And how do we eliminate this inactive hormone? "Through urine, where no traces of active thyroid hormone have been detected."
Further evidence for the safety of the thyroid hormone contained in anti-cellulite creams? "Scientific studies were conducted at the Universities of Milan** comparing the results on women who had been given placebo creams and other anti-cellulite drugs. Well, the evidence not only found the efficacy of topical cellulite drugs, but documented no alteration of FT3 and FT4 hormone levels in the blood, i.e., those indicating thyroid malfunction. Nor is the value of TSH, that is, the hormone produced by the pituitary gland related to thyroid hormone secretion, affected."
The conclusion is that local applications of levothyroxine creams do not interfere with the eventual therapy for hypothyroidism, which instead is absorbed to via completely different mechanisms, i.e., systemic.
*Santini F. et al Role for inner ring deiodination prevented transcutaneous passage of Thyroxine. The Journal of Clinical Endocrinology & Metabolism.
**Galbiati G. et al - Clinical, double-blind study of a topical preparation versus placebo in women with edematofibrous panniculopathy localized to the thighs, Italian Journal of Dermatology and Venereology
