What is Tetrahydrobiopterin (BH4) and How Can I Make More of it?

[Kia17]

Tetrahydrobiopterin (BH4, sometimes THB) is a vital cofactor for numerous enzymes in the body, including those involved in the formation of nitric oxide (NO), and the key neurotransmitters dopamine, serotonin and epinephrine.

mygenefood.com/blog/tetrahy...

[Kia17]

What Decreases BH4?

Heavy metals such as Mercury, Lead, Aluminum and Iron

High protein diet

Hydrogen peroxide

Hyperammonia

Inflammation

Methotrexate, which inhibits DHFR

Oxidative Stress/Damage

Peroxynitrite

Sun/UV

The mutations listed above

[Kia17]

What Increase BH4?

Chronic Pain (adaptive response)

Exercise

Far-Infrared

Fenofibrate

Folate/Methylfolate is a potent peroxynitrite scavenger

Losartan

Nitrites

Royal Jelly

SAM-e

Statins/HMG-CoA reductase inhibitors

Vitamin C

mybiohack.com/blog/bh4-tetr...

[Kia17]

Tests

23andMe (look at raw data)

Neopterin/Biopterin Profile (Urine)

[Kia17]

Here is a summary of the BH4-related biochemical transformations:

Phenylalanine hydroxylase (PAH) enzyme to convert Phenylalanine (PHE) to Tyrosine (TYR)

Tyrosine hydroxylase (TH) enzyme to convert Tyrosine to L-DOPA (DOPA)

Tryptophan hydroxylase (TPH) enzyme to convert Tryptophan to 5-Hydroxytryptophan (5-HTP)

Nitric oxide synthase (NOS) enzyme to convert a Arginine (ARG) to Nitric oxide (NO)

The enzyme DHFR may recycle BH2 into BH4.

This would be after exogenously administered BH4 has been oxidized into BH2.

[Kia17]

Nitric Oxide Production

BH4 is important for nitric oxide synthases and when it is missing, enzymes become "uncoupled". This uncoupling produces Reactive Oxygen Species (ROS) rather than NO.

[billPD]

is there a test to measure BH4 levels?

can supplementation increase BH4 level?

[Kia17]

Neopterin/Biopterin Profile (Urine) Test. It’s very complicated pathway and one can’t simply supplement with BH4.