Should I take vitamin B6 to promote hair growth?
Should I avoid vitamin B6 since it might inhibit 5-alpha reductase (5AR) and lower DHT?
This is a common question based on only available 2 studies. In short, the answer is no, vitamin B6 doesn’t lower DHT, but read on for the nuance.
But first, let’s look at what vitamin B6 is.
Vitamin B6 is a water-soluble vitamin that occurs in 6 different forms.
Plant foods are high in pyridoxine whereas animal foods are rich in pyridoxal and pyridoxamine.
These forms can interconvert in the body. The active form in the body is pyridoxal-5-phosphate (P5P), which is involved in over 150 enzymatic reactions. This doesn’t mean that the other forms are useless. They also have benefits of their own.
Vitamin B6, 5-alpha reductase and DHT
Only 2 in vitro studies show that B6 might inhibit 5AR.
#1 The first in vitro study showed that a specific form of B6 can inhibit 5AR.
“Pyridoxine hydrochloride significantly increased the activity of 5 alpha-R, 3 alpha- and 17 beta-HSD, but pyridoxal hydrochloride had an inhibitory influence on 5 alpha-R and showed no effect on 3 alpha-HSD activity at the prostate level. Male rat anterior pituitary, basal hypothalamus or amygdala incubated with pyridoxal phosphate and pyridoxal hydrochloride showed modified enzymatic activities. Pyridoxal hydrochloride showed an inhibitory effect on 5 alpha-R in the rat pituitary and basal hypothalamus as well as in the rat prostate.” (R)
The only form that inhibited 5AR is pyridoxal hydrochloride, not pyridoxine or pyridoxal phosphate (P5P).
#2 The next in vitro study (in skin cells) looked at the effect of vitamin B6 (specifically pyridoxine) on 5AR. As a side note, the skin has a lot of 5AR compared to other tissue.
“vitamin B6 (pyridoxine) had no effect on 5a-reductase activity when added alone or together with azelaic acid.” (R)
As you can see, conflicting results. In the first study, pyridoxine promoted 5AR, whereas, in the 2nd study, it has no effect. It could be because, in the 1st study, they used pituitary, hypothalamic, amygdala and prostate cells whereas, in the 2nd study, they used skin cells.
Summary
1) Pyridoxal hydrochloride inhibited 5AR in the pituitary, hypothalamus, amygdala and prostate, whereas 2) pyridoxine boosted 5AR and 3) pyridoxal phosphate had no major effect.
The 2 main forms that you can buy are pyridoxine hydrochloride and pyridoxal phosphate, so even if pyridoxal hydrochloride inhibited 5AR, you can’t buy it anyway.
Don’t be fooled that DHT is bad for you, I’ve done many articles showing that DHT is actually good for you:
- Testosterone (and DHT) on prostate cancer: we’ve been LIED to!
- Why DHT doesn’t cause hair loss
- Toxic DHT: can DHT ever be too high
- The truth on DHT: what the research shows
4 mechanisms on how vitamin B6 can increase DHT
1) Vitamin B6 promotes thyroid function
B6 (pyridoxine HCL) treatment in rats restored B6 deficient hypothyroid (R). Of the many nutrients required for proper thyroid function, B6 is one of them.
Related article:
2) Vitamin B6 lowers inflammation
Plasma PLP concentrations are inversely related to markers of inflammation such as C-reactive protein (TNFα, IL-6, IFN-γ, COX-2 and iNOS expression).
Elevated inflammatory markers, such as IL-6 and CRP, have significant inhibitory effects on the synthesis of DHT by inhibiting 5-AR (R). Oxidative stress also has similar inhibitor actions (R, R).
3) Vitamin B6 lowers prolactin
Vitamin B6 is involved in the synthesis of dopamine. And dopamine is the main antagonist to prolactin.
According to this study, pyridoxine HCL lowered prolactin by 42% in short-stature children, without affecting growth hormone (R). This could also be due to the TSH-lowering effect (by improving thyroid function), since TRH, which promotes the release of TSH, also promotes the release of prolactin.
Prolactin inhibits 5-AR in normal men (R). Luckily, it can quickly be reversed as 5-AR is reactivated within 48-72 hrs after normalization of prolactin levels. You can read more here on lowering prolactin here…
Related articles:
- 8 uncommon herbs that lower prolactin and restore dopaminergic neurotransmission
- Lower prolactin: a guide 10 step guide
4) Vitamin B6 increases 5AR cofactor
Vitamin B6 is a cofactor for glucose-6-phosphate dehydrogenase (G6PD), which is the rate-limiting enzyme of the pentose phosphate pathway, which is a major source of NADPH (R).
NADPH is used as a cofactor by 5AR to synthesize DHT.
Vitamin B6-deficiency caused marked diminution in the G6PD activity (R)
Related article:
Vitamin B6 on hair growth
Many people think that high levels of DHT play an important role in hair loss and that low DHT is required for healthy hair growth. That’s why people use DHT blockers to lower DHT levels, such as saw palmetto extract, green tea extract, pumpkin seeds, pumpkin seed oil, nettle root extract, pygeum bark, essential fatty acids (linoleic and alpha-linolenic acid), etc.
Pharma drugs that block DHT include finasteride and dutasteride, but they have a lot of side effects, such as depression and anxiety, sexual dysfunction, etc. For that reason, they created a topical finasteride product to prevent it from entering the blood stream, but even topical use of finasteride can significantly lower serum DHT and still cause side effects.
As you’ve seen in the study on skin cells above, vitamin B6 doesn’t inhibit 5AR on its own.
Similar to other oral supplements used for androgenetic alopecia, such as vitamins (vitamin A, vitamin C, vitamin E, biotin, pantothenic acid, folic acid), zinc, etc, vitamin B6 promotes the growth of hair follicles without affecting DHT. Rather it affects pathways that participate in hair follicle development and cell growth, prolonging hair follicle growth and delaying the onset of telogen (R). This will help with thicker hair and better hair strength and density.
In many of the same ways vitamin B6 increases DHT, it will also help with natural hair growth; namely by lowering prolactin, lowering inflammation and increasing glutathione. High prolactin and inflammation, poor blood flow and blood circulation, B vitamin deficiency, vitamin D deficiency, etc, leads to male pattern baldness.
Summary
I personally would not supplement vitamin B6 in general unless I had a big deficiency (or significantly elevated prolactin) that needs correcting right away. I would try to get all the important nutrients from a healthy diet consisting of specific food sources, such as dairy products (as long as you’re not sensitive to it), eggs, meat, organ meat, honey and fruits and starches that you tolerate well. Eating a low inflammatory, nutrient dense diet is going to give you the best results.
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