Tuesday, April 12, 2011

Soy Isoflavones and Chili Pepper for Hair Growth – Experiment Update

Spicy peppers contain capsaicin, which should promote hair growth.
Spicy peppers contain capsaicin, which should promote hair growth. (Photo by Jonathon W)

Several readers have been asking for an update on my hair growth experiment with soy isoflavones and capsaicin. I admit it's long overdue, so here goes!

First some background on the experiment. Why soy isoflavones? I know there are a lot of people who think soy is the ultimate poison, and while I'm not a big fan of soy as a food, the science behind isoflavones and hair growth is strong enough for me to give it a go. Soy isoflavones have been shown to increase IGF-1 in the skin, which in turn promotes hair growth. Although soy also reduces DHT in rats and in humans, the effects on IGF-1 seem to be the primary way through which isoflavones grow hair.

Capsaicin seems to have a similar effect on IGF-1, and in both mice and humans, the combination of soy isoflavones and capsaicin appears to be more effective than capsaicin alone. I have not seen a direct comparison of soy isoflavones and soy isoflavones + capsaicin, however, so it's unclear how important capsaicin really is. Nevertheless, I chose to take both for the experiment.

The participants in the study were given a capsaicin supplement, but I decided to take the natural route and just add cayenne pepper or chili powder into my food instead. It's difficult to determine just how much capsaicin I've been ingesting this way, since the capsaicin content depends on a lot of variables. As I wrote when the experiment began:

The only problem is that it's pretty difficult to estimate the amount of capsaicin; a tablespoon of ground chili will contain anywhere between 0.8 mg and 480 mg of capsaicin. In the study, 7 mg per day was consumed, so if I manage to eat a tablespoon, I should have decent odds of ingesting at least as much capsaicin.

The amount of isoflavones I've been eating, on the other hand, has been easy to measure. One capsule contains 60 mg of isoflavones, which is 15 mg less than in the study.

And what about the results? I've not taken any pictures, since unlike in the retinol experiment, there's not much visible going on. I haven't cut my hair in years, and the length of my hair is still the same as it was before (the maximum length of your hair is genetically determined), so it's safe to say that isoflavones and capsaicin haven't done anything in that department.

I also haven't seen any increase in the rate of hair growth, which is perhaps a bit surprising, since you might expect an increase in IGF-1 to increase the speed at which hairs grow. But then again, I have no reliable way of measuring my IGF-1 levels either. I've simply been looking at a few hairs and measuring how much they grow each month.

The one thing I noticed during this experiment is something of a shed in the beginning. There's no way to be sure it's the isoflavones and capsaicin working, but I haven't noticed anything similar with the other experiments. After a few months, I seemed to not only shed more hairs in general, but especially from the front of the scalp. Moreover, many of these hairs had not grown to their full length yet.

As most of you probably know, that can be a good or a bad sign. A lot hair growth drugs, including finasteride, cause an initial shed, after which the hairs grow back stronger and healthier. Then again, inflammation also causes hairs to shed earlier than they should, only they grow back weaker every time.

At this point, it's still too early to tell, since the new hairs are still growing. At least on the surface they look fine. What's funny is that there are some spots where several hairs are pretty much the exact same length. The two possible reasons is that those hairs were shed at the same time and now regrowing, or that the isoflavones and capsaicin increased the number of hair follicles. I suspect the former, but I can't be sure.

So what's the next step? I've already ordered a second bottle of isoflavone capsules, and since I like to use chili in my food anyway, I'll pretty much keep doing what I've been doing so far. If I see any dramatic changes, I will post about them, but if not, I will just consider the isoflavones and capsaicin thing a preventative measure and move on to more interesting experiments.

That's it for today. I hope you found this update useful, and if you have further questions or you've done a similar experiment of your own, please let us know in the comment section.

For more information on hair growth, see these posts:

Topical Retinoids Increase Hair Growth in Most People
BioSil, JarroSil & Beer – Silicon Experiment Conclusion
Zinc Pyrithione Reduces Shedding and Moderately Promotes Hair Growth
Eclipta Alba Extract Grows Hair Quicker than Minoxidil

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10 kommenttia:

Anonymous April 12, 2011 at 9:22 PM  

Yeah JLL,

Just came across your blog today. I may be one of your youngest readers, at 18 year old, but I want to say I'm really enjoying all your articles, keep it up.

clare April 12, 2011 at 11:12 PM  

What effect if any do you think the experiment is having on your body hair?

JLL April 13, 2011 at 10:01 AM  


Good question. I think it's business as usual, it hasn't slowed down, but I also haven't noticed any new hairs.


Sandy April 13, 2011 at 10:27 PM  

Any thoughts on saw palmetto?

I'm taking dutasteride, but not for much longer. It works but I'm too concerned about long term effects.

Can't say I'd be too keen on taking isoflavones. Too much scary stuff out there on soy.

JLL May 26, 2011 at 10:06 AM  


I think saw palmetto is at best a less effective version of finasteride. The more effective, probably the more side effects too. But the good part is that you don't need a prescription for it.

As for soy, I think there's a lot of misinformation out there. I'm by no means a fan of replacing meat with soy, but just because something has "phytoestrogens" in it doesn't make it a bad thing.


michael October 10, 2011 at 7:24 PM  

hi jll,

any updates?


Karl November 4, 2011 at 2:41 PM  

Hey JLL, have you heard of the Japanese fermented soya beans called natto? (http://en.wikipedia.org/wiki/Natt%C5%8D) I'm guessing it contains a fair amount of isoflavones, so since seeing your article last night I've decided to start eating 45g of the stuff on top of about 150g of cold tofu with some korean kimchi on top for flavour (and added capsicum). It's really easy to buy here as I'm in Japan, I can get 3 pots at 45g each for 100 yen! I'm going to give it go for 6 months, to see if I get any thickening on my crown/hairline...fingers crossed!

this website October 13, 2012 at 9:05 AM  

Why soy isoflavones? I know there are a lot of people who think soy is the ultimate poison, and while I'm not a big fan of soy as a food

TMoney February 12, 2013 at 4:24 AM  

I'm closing in on my 5th month taking 1-2 mg of capsaicin, 135 mg of soy isoflavones and 725 mg of green tea extract. I thought your post was interesting because I've experienced shedding and noticeable thinning in the front as well. This is odd considering my most visible hairloss has been on my crown. I'm also running under the assumption that "things that work" have shedding first. I've let my hair grow in general and plan on cutting it again (one length short all over) to compair it to earlier photos. I'd like to think this is a good sign but who knows?

I'd love to see an update from you. Peace - T.

spearIT November 20, 2014 at 2:46 AM  

Any updates JLL?

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