sally-ann tarver , a former president of the trichological society now based at the cotswold trichology centre , recommends florisene pills -lrb- £ 15.95 , lambertshealthcare.co.uk -rrb- , which contain iron , because these do n't seem to cause the digestive irritation linked to standard pills .
after six months , the hairs in those taking the supplement had increased in width by an average of 7 per cent compared with the placebo group .
however , a clinical trial looked into the efficacy of the supplement viviscal -lrb- £ 29.99 , boots -rrb- .