Isotope analysis
A recent development in forensic science is the isotopic analysis of hair strands. Hair has a recognisable growth rate of 9-11mm per month or 15 cm per year. Human hair growth is primarily a function of diet, especially drinking water intake. The stable isotopic ratios of drinking water are a function of location, and the geology that the water percolates through. Sr, Sr and oxygen isotope variations are different all over the world. These differences in isotopic ratio are then biologically 'set' in our hair as it grows and it has therefore become possible to identify recent geographic histories by the analysis of hair strands. For example, it could be possible to identify whether a terrorist suspect had recently been to a particular location from hair analysis. This hair analysis is a non-invasive method which is becoming very popular in cases that DNA or other traditional means are bringing no answers.
Prostaglandin D2
A 2012 research paper indicates a causal link between elevated levels of localized PGD and hair growth inhibition. Applied topically, the researchers found PGD prevents hair growth, and mice that were genetically inclined to produce higher levels of PGD had inhibited hair growth. The researchers also found PGD levels were much higher in balding scalp tissue than nonbalding scalp tissue, through increased levels of prostaglandin D2 synthase. The paper suggested that inhibition of hair growth involved binding of PGD to a receptor called GPR44, and that GPR44 therefore would be a therapeutic target for androgenic alopecia in both men and women with hair loss and thinning. Because PGD's relation to asthma has been known for several years, several drugs that seek to reduce the effect of PGD through blocking the GPR44 are already in clinical trials.