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Retin A - Not good according to this study = CATAGEN



1Tanja Spexard, 1Ralf Paus, 2Ursula Halsner, 2Sibylle Eberle, 1Karoline Krause, 1Ingrid Moll und 1Kerstin Foitzik. 1Department of Dermatology, Univ. Hosp. Eppendorf, Hamburg, Germany, 2ArteMedicMeditra GmbH, Gräfelfing, Germany

Retinoic acid can have adverse effects on human hair follicles. While systemic intake of retinoic acid is able to induce telogen effluvium, topical treatment of human scalp hair follicles with tretinoin may also result in a prolonged anagen phase. Therefore, we have investigated the influence of all-trans retinoic acid (RA) on the growth of human hair follicles in culture.

Human anagen hair follicles were dissected, and organ-cultured in supplemented Williams E Medium for 2, 4 or 6 days with retinoic acid (10-8, 10-11 M), and length of the hair shaft was measured every second day, before follicles were embedded for cryosectioning. Hair shaft length decreased already significantly after two days in the RA-treated group, compared to control. Staging of the hair follicles showed that approx. 80% of the RA-treated hair follicles at day 6 had entered catagen, compared to 30% of catagen follicles in the control group. This corresponded to a relative upregulation of TUNEL+ cells and a downregulation of Ki67+ cells in the RA-treated follicles. Since TGF-ß2 has recently been implicated as an inducer of catagen in human hair follicles, we next studied whether RA treatment had any affect on follicular TGF-ß2 expression. TGF-ß2 immunoreactivity was detected in the outer root sheath (ORS) of normal, untreated anagen VI scalp hair follicles. The lower portion of the hair bulb and the dermal papilla were negative for TGF-ß2. In catagen follicles, TGF-ß2 was also expressed in the regressing epithelial strand. After 4 days of RA treatment, TGF-ß2 was significantly upregulated in anagen hair follicles in the dermal papilla and the dermal sheath. In addition, the intensity of TGF-ß1 and TGF-ß receptor type II (TGFRII) immunoreactivity was increased in the ORS of RA-treated hair follicles, compared to control. We demonstrated that RA is indeed capable of inducing catagen in human hair follicles in vitro and that RA upregulates TGF-ß2 in the dermal papilla and TGFRII expression in the ORS. This shows that RA can induce catagen, possibly via induction of TGF-ß2 and upregulation of its receptor.


I wonder if that has anything to do with the fact that the study was done in vitro? Things might have been different when put in an artificial environment outside the living organism.


I have been saying this for years - thanks for posting it. There are products advertised on this website that have Retin-A as the basis of their so-called increased growth when used in conjunction with minox. Although these products are very easy to apply and offer a non-greasy alternative to regular minox, they led to a beet-red, inflamed scalp and rapid hair loss for me - this study would explain the inflammation via upregulation of TGF-beta. THANK YOU for posting this!



A contradicting study,


Topical tretinoin for hair growth promotion.
Bazzano GS, Terezakis N, Galen W.

Topical all-trans-retinoic acid (tretinoin) alone and in combination with 0.5% minoxidil has been tested for the promotion of hair growth in 56 subjects with androgenetic alopecia. After 1 year, the combination of topical tretinoin with 0.5% minoxidil resulted in terminal hair regrowth in 66% of the subjects studied. Tretinoin was shown to stimulate some hair regrowth in approximately 58% of the subjects studied. One female subject with pronounced alopecia for more than 20 years had regrowth of hair using only tretinoin for a period of 18 months. Tretinoin has been shown to promote and regulate cell proliferation and differentiation in the epithelium and may promote vascular proliferation. These factors are important for hair growth promotion.

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It’s been known for years that oral retinoids (ie, Accutane) can cause hair loss, sometimes extreme. I have always been a little reluctant about topical retinoids for this reason.


» It’s been known for years that oral retinoids (ie, Accutane) can cause hair
» loss, sometimes extreme. I have always been a little reluctant about
» topical retinoids for this reason.