Soy isoflavones, androgens and hair growth

[JLL]

Since the case for soy as a treatment for hair loss seems unclear, I'm going to do blog posts of all the published papers related to soy and hair growth and post them here. I know this has been discussed before, but most people probably don't have access to the full papers, so I hope you find the posts useful. The first one is already up.

Soy Isoflavones Reduce DHT, Increase Testosterone

In the first experiment, rats in the treatment group were given soy flour with their normal chow. In the second experiment, rats in the treatment groups were given either a soy methanol extract or semipurified soy isoflavones.

Rats on the soy flour diet had significantly lower DHT levels than rats on the control diet. Similarly, the DHT levels of the rats on the soy isoflavone diet were about 60% lower DHT than in the control group. --

Rats on the soy flour diet had similar levels of testosterone + dihydrotestosterone (T+DHT) as the control group. Since their DHT levels were lower, however, this means that there was an increase in testosterone from eating the soy flour diet. In the soy isoflavone diet, this effect was even clearer; not only was the reduction in DHT balanced by an increase in testosterone, but the total T+DHT levels were much higher than they were before the diet.

See the link for more info.

 

[elvis123]

There are way too many studies about soy isoflavones with conflicting results...Some say it's good, some say it's bad.....

 

[JLL]

The second post in the series is up.

Soy protein isolate reduces DHT in healthy young men.

Serum DHT was significantly reduced following the consumption of both a low-isoflavone and high-isoflavone soy protein isolate compared to a milk protein isolate. The reductions were 9.4% and 15%, respectively. The DHT/testosterone ratio was also decreased by 9.0% and 14%, respectively.

The reduction in the DHT/testosterone ratio suggests an inhibition of 5-alpha-reductase. However, 3-alpha-AG, a marker of 5-alpha-reductase activity, was not significantly affected. Levels of sex hormone-binding globulin (SHBG) were also not significantly different between the diets.

 

[SuperMeh]

What are the negatives of Soy then? I remember reading into this a lot quite awhile ago, and decided against it, I read about hypothyroid disorders occurring in some people with iodine deficiencies, but I'm sure must've been something more than that to put me off.

I don't see it mentioned much so it can't be that widely used. Confusing! Seems good =]

 

[elvis123]

yea is it good or bad??

 

[hairrific]

At the end of the study, serum estradiol and estrone were increased by the low-isoflavone diet compared with the milk protein diet.

And is that good or bad? How much of an increase, they did not specify!

 

[JLL]

Estradiol levels

Milk protein: 77.9
Low-isoflavone soy: 85.1
High-isoflavone soy: 82.0

Estrone levels

Milk protein: 155.7
Low-isoflavone soy: 172.4
High-isoflavone soy: 164.1

Whether it's good or bad is hard to say. I guess it depends. Is lower DHT good or bad? Well, it may be good for hair loss and bad for something else. Same with most things.