Dihexa and autism: separating peptide hype from thin evidence

What did @drkendalstewart actually say?

The core claim here is striking: "We have seen more children become nonverbal from nonverbal" — which, in context, means children moving from nonverbal to verbal — "in the last two to three years using Dijhekse than we saw in the decade before that." That's a direct assertion that Dihexa, a synthetic peptide, is driving a measurable shift in communication outcomes for autistic children in this clinic's patient population. The creator also frames this as part of a broader peptide therapy approach, saying they're "using a ton of peptides to answer some of these genetic weaknesses." That phrase alone deserves scrutiny. There's no established genetic mechanism that Dihexa is known to correct, and the framing of autism as a set of "genetic weaknesses" to be patched with peptides is not a position supported by current neurodevelopmental science. What we have here is a clinician making bold outcome claims for an off-label compound based entirely on anecdotal clinical observation.

Does the science back this up?

No. Not even close. Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a peptidomimetic compound developed at Washington State University. The foundational research, primarily from McCoy et al. (2013, Journal of Pharmacology and Experimental Therapeutics), showed it potentiated HGF/MET signaling and improved spatial memory in aged rats. That's it. Rodents. Cognitive aging models. There are no published randomized controlled trials of Dihexa in humans, let alone in autistic children. There are no peer-reviewed case series. There are no FDA-cleared indications. The leap from "improved memory in aging rats" to "children becoming verbal" is not a small interpretive stretch. It is an evidence gap so large you could lose a clinical trial in it. The claim that more children became verbal in two to three years of Dihexa use than in a decade prior cannot be evaluated because there is no control group, no baseline data, no published methodology, and no independent verification of any kind.

What did they get wrong (or right)?

Wrong: The outcome claim is unverifiable and irresponsible as stated. Saying a peptide produced more verbal children in two years than were seen in a decade is a comparative effectiveness claim. Making that claim without published data, a control arm, or even a defined patient population is not how medicine works. It's how hype works. Also wrong: framing this as evidence of peptide therapy's promise in autism when the human evidence base is effectively nonexistent for Dihexa specifically.

Partially right, grudgingly: Peptide research in neurodevelopment is a legitimate area of scientific inquiry. Compounds like Semax have been studied in Russian clinical contexts for cognitive and neurological applications. The general interest in neuropeptides is not fringe. But interest and evidence are different things, and conflating them is the core problem with this video.

• No human clinical trials of Dihexa exist in the published literature as of 2024.
• Autism communication gains in children do occur, frequently, with established interventions like ABA, speech therapy, and AAC. Attributing gains to a concurrent compound without controls is a classic confounding error.
• McCoy et al. (2013) explicitly focused on aged animal models, not pediatric neurodevelopment.

What should you actually know?

If you're a parent of an autistic child and this video caught your attention, here's the honest picture. Children who are nonverbal at age three do sometimes develop spoken language, with or without any specific intervention. This is documented in the literature. Wodka et al. (2013, Pediatrics) found that roughly 70% of minimally verbal autistic children gained meaningful speech by early adolescence. Any treatment given during a developmental window where spontaneous gains are possible will appear to work if you're not measuring carefully. This is not cynicism. It's basic epidemiology.

Dihexa is not approved by the FDA for any indication. It is not approved for pediatric use. It is not approved for autism. Compounded versions circulate in the peptide therapy space, but compounded drugs are not equivalent to drugs that have completed clinical trials. Parents considering any off-label compound for their child should demand published human safety data, not clinic anecdotes delivered to camera.

The broader peptide therapy space has legitimate applications under investigation, but those applications need to be evaluated compound by compound, population by population. Enthusiasm is not data.

Bottom line

This video makes a specific, comparative outcome claim about an experimental compound in a vulnerable pediatric population with zero published evidence to support it. The creator may believe what they're saying. That does not make it accurate. Until Dihexa is studied in autistic children in a controlled setting, any claim about its effects on verbal communication is speculation dressed up as clinical experience.