Thiamine
For fatigue despite supplementation with other vitamins
Most of the experts we follow recommend it.
Thiamine can be helpful when fatigue persists despite other vitamin support.
Who is behind it
Voices including a nutritional sciences PhD, an endocrinology-trained performance coach and a certified naturopath.
How strong the research is
Well studied in published research, as well as in practice.
In their words
“I don't think thiamine transport is going to compete with other B vitamins. And so I don't think taking them at a different meal from the others is going to do anything about that.”
a nutritional sciences PhD
If thiamine deficiency is suspected, elevations in alanine and low thiamine levels can confirm it.
Thiamine may decrease menstrual bleeding by enhancing estrogen detoxification and glucose oxidation, supported by recent and historical studies.
Increasing DAO enzyme function can reduce histamine levels linked to migraines
Most people struggle to get enough thiamine from their diet and modern stressors deplete it synergistically.
Thiamine can be crucial for managing PCOS symptoms and increases fertility rate by supporting energy production, glucose metabolism, gut health, nervous system, and antioxidant functions.
B1/thiamine can be deeply leveraged to enable brain energy metabolism to run incredibly well.
With care
Some of the minds attach conditions. These are worth reading before you begin.
Sometimes supplementation can be leveraged due to difficulty in obtaining sufficient amounts from diet alone.
The expert finds 300mg effective for himself due to severe long-term depletion and modern stressors but advises case-by-case consideration and a food-first approach.
Thiamine may be required in higher amounts due to losses from foods high in thiaminases and increased metabolic demand, and some clients respond well to thiamine alone.
Talk it through
Entrain shows what the experts teach, so you can make better decisions with your own clinician. It does not diagnose or prescribe. If something is worrying you, start there.
How this reading was made
Every line here comes from a doctor, scientist or coach speaking publicly, and links to the moment they said it. Entrain listens for where independent experts arrive at the same place on their own, and shows where they part ways. Well studied in published research, as well as in practice.
Some statements come from sponsored segments or people speaking about their own products. They are marked where they appear and count for less. Last refreshed 23 September 2026.
The research beneath it
- Thiamine deficiency and oxidative stress induced by prolonged metronidazole therapy can explain its side effects of neurotoxicity and infertility in experimental animals: Effect of grapefruit co-therapy.Human & experimental toxicology, 2020
- Thiamine preserves mitochondrial function in a rat model of traumatic brain injury, preventing inactivation of the 2-oxoglutarate dehydrogenase complex.Biochimica et biophysica acta. Bioenergetics, 2018
- Long-Term Treatment with High-Dose Thiamine in Parkinson Disease: An Open-Label Pilot Study.Journal of alternative and complementary medicine (New York, N.Y.), 2015
- High-dose thiamine as initial treatment for Parkinson's disease.BMJ case reports, 2013
- High prevalence of low plasma thiamine concentration in diabetes linked to a marker of vascular disease.Diabetologia, 2007
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