Effectiveness and Safety of Hair Growth Formulation Containing Tectona grandis L.f (Teak) Leaf Extract: A Randomized, Double-Blind, Placebo-Controlled Study on Males with Androgenic Alopecia

Background Androgenic alopecia (AGA) is commonly known as male patterned baldness. A high level of dihydrotestosterone (DHT) plays a significant role in AGA development. Inhibition of the enzyme steroid 5-alpha reductase (S5AR), responsible for converting testosterone into DHT, has been shown to delay the progression of AGA. Teak (Tectona grandis L.f) leaf extract exhibited a potent S5AR inhibitory activity. To prove the effectiveness and safety of teak leaf extract as a hair growth promotor, a double-blind, randomized placebo-controlled trial was conducted.Methods Eighty-one AGA subjects were randomly assigned to receive either a hair tonic containing 1% teak leaf extract (HT-teak), 5%minoxidil (positive control), or a placebo administered twice daily, for 24 weeks. Efficacy was assessed through target area hair count (TAHC), anagen-to-telogen ratio (A/T), hair shedding every 4 weeks, and patients' subjective assessments of hair regrowth were assessed at the end of the experiment. Data was analyzed using repeated measure ANOVA.Results Both the HT-teak and minoxidil groups exhibited a significant increase in TAHC and A/T, along with a decrease in hair shedding compared to baseline values. Conversely, the placebo group showed no observable signs of hair regrowth. Furthermore, the HT-teak group reported the highest satisfaction scores, and there were no indications of skin irritation or systemic effects on sexual dysfunction and palpitation after 24 weeks of HT-teak application.Conclusion Teak leaf extract, as incorporated in HT-teak, demonstrates potential as an alternative mild hair growth promoter for individuals with AGA, offering both efficacy and safety.Trial registration This study was retrospectively registered on International Standard Randomised Controlled Trial Number (ISRCTN.com); ISRCTN24541842 (registered on January 8, 2024).