J. Soc. Cosmetic Chemists 18 439-453 (1967) ¸ 1967 Society of Cosmetic Chemists of Great Britain The clinical evaluation antidandruff shampoos of N.J. VAN ABBE and PATRICIA M. DEAN* Presented at the Symposium on "Product Testing", organised by the Society of Cosmetic ehdmists of Great Britain in Eastbourne, Sussex, on 15th November, 1966 $yn0p$is•Assessment of the efficacy of a treatment for dandruff demands a rigidly controlled methodology, comparable to that employed in other types of clinical testing. Experimental techniques are illustrated and discussed, with emphasis on the need for careful training of observers, who may then be able to derive meaningful results from a study of human volun- teers using an antidandruff shampoo. In a previous communication (1), the study of dandruff on volunteer human subjects was described in detail, with emphasis on methods of studying the disorder itself rather than its treatment. Shampoos con- taining various active constituents represent the accepted means of providing •nedication for dandruff and several papers (2-4) report clinical investigations of these and other means of applying the active ingredient. In recognition of the need to devise techniques of scientific validity for evaluating potential therapeutic measures, this paper is intended to review some of our own experiences critically. As before, attention will be confined principally to the manifestation of dandruff as visible scaling, i.e. desquamation in excess of and in fragments larger than that due to a simple shedding of the horny layer of the epidermis. We are not, in the present context, interested in the causation of dandruff, although this must obviously have a bearing on the clinical aspects our *Beecham Toiletry Division, Brentford, London. 439

440 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS concern is to assess the feasibility and reliability of various ways of eval- uating potential treatments. PRINCIPLES OF CLINICAL TESTING Dandruff is a chronic abnormality of the scalp and, as in the case of chronic diseases generally, the prognosis for any individual sufferer at a given point in time is uncertain. In other words, when a treatment is administered to a subject, it is difficult to decide whether future progress (favourable or adverse) is due to the treatment or to spontaneous changes. The pre-treatment phase shown in Fig. I shows how dandruff fluctuates spontaneously if a course of treatment was initiated at a time when the 35' (PLACEBO) Figure 1 Results of 17 weeks' treatment with placebo shampoo on a case of moderate dandruff (Detailed method of inspection). level was high, there would obviously be a distinct hazard that subsequent inspection would register a reduction in dandruff although this might be wholly independent of the treatment given. Fluctuation of this nature can be taken care of to some extent by using sizeable panels of subjects, so that the purely random effects tend to cancel out. However, if progress under treatment is compared only with pre-treatment levels, there is an indeter- rainable risk that extraneous factors may be operative during treatment, possibly having a greater influence on the dandruff levels than the treat- ment itself. Such an irrelevant feature could well be climatic, for an effect of this nature during dandruff treatment has been noticed previously (1).