What did @wholebodyhealingwithjen actually say?
The creator made a sweeping case for thiamine (B1) as a near-universal fix for a long list of serious conditions. She said B1 is "a primary cofactor in the metabolic reactions that allow us to make energy on a cellular level" and connected deficiency to insulin resistance, brain fog, dementia, low vagal tone, POTS, dysautonomia, multiple sclerosis, ALS, gastroparesis, SIBO, and peripheral neuropathy. She recommended fat-soluble forms like benfotiamine or allithiamine over standard thiamine HCl, told viewers to "experiment on yourself" with dosing, and said she has "almost all" her clients supplementing B1. She also claimed a client saw "a major reduction in negative self-talk" after starting B1.
That is a significant list of claims, spanning metabolic disease, neurological conditions, and mental health. Some of it is grounded in real biochemistry. Some of it stretches the evidence well past its breaking point.
Does the science back this up?
The core biochemistry is solid. The extrapolations to MS and ALS are not. Thiamine is a genuine cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, enzymes that are non-negotiable for ATP production. That part checks out. Lonsdale and Marrs (2012, Nutrients) documented thiamine's role in autonomic nervous system function, and there is real evidence linking deficiency to peripheral neuropathy and Wernicke's encephalopathy.
The claim that B1 deficiency causes or contributes to multiple sclerosis and ALS, however, is not supported by clinical evidence. There are isolated case reports and hypotheses in the literature, notably from Costantini et al. (2013, BMJ Case Reports) on high-dose thiamine in MS fatigue, but these are preliminary findings, not established links. Extrapolating from "nerves need thiamine" to "thiamine deficiency causes ALS" is a logic leap the evidence does not support. The SIBO claim has slightly more mechanistic plausibility, since gut motility does depend on enteric nervous system function, but direct clinical trials connecting thiamine repletion to SIBO resolution are thin.
What did they get wrong (or right)?
Credit where it is due: the claim that standard thiamine HCl has lower bioavailability than benfotiamine is accurate. Combs and McClung (2017, The Vitamins) confirm benfotiamine has superior lipophilicity and tissue uptake. The recommendation to prioritize liver, pork, and organ meats as food sources is also correct and consistent with USDA nutrient data.
What she got wrong, or at least seriously oversimplified, is the implied causal chain. Saying B1 deficiency is implicated in MS and ALS based on mechanistic logic is not the same as saying supplementing B1 treats or prevents those diseases. These are diagnosed neurological conditions with complex, multifactorial pathology. Presenting them in the same breath as correctable B1 deficiency symptoms is misleading to a general audience. The "negative self-talk" anecdote is unverifiable and has no clinical backing whatsoever. Telling viewers to "experiment on yourself" with high doses of a supplement is also irresponsible, even if thiamine has a wide safety margin.
What should you actually know?
Thiamine deficiency is real and underdiagnosed, particularly in people with alcohol use disorder, bariatric surgery histories, or diets high in refined carbohydrates. The Nurses Health Study and other large cohort data show suboptimal intake is more common than clinicians expect. If you have persistent fatigue, neuropathy symptoms, or unexplained anxiety, asking your doctor to check thiamine levels is reasonable.
But "B1 is involved in nerve function" does not mean B1 supplementation treats ALS, MS, or dysautonomia. If you have any of those diagnoses, managing them requires a neurologist, not a TikTok supplement protocol. Benfotiamine and allithiamine are legitimate forms with better absorption, and supplementation at reasonable doses is low-risk for most people, but the framing here dramatically overstates what the evidence actually shows. Work with a clinician before assuming chronic symptoms are a nutrient deficiency.