Low levels of Oxytocin has been associated with autism. The impact of administration of Oxytocin is fuzzy.
Animal model research has documented that the administration of OXT and AVP was able to rescue autistic traits and increase social skills [119,120,121]. In humans, there is some evidence that the administration of oxytocin reduces some dysfunctional behaviors associated with autism, especially social skills, repetitive behaviors, anxiety, irritability, and self-injurious behaviors [122,123,124]. However, a recent meta-analysis that reviewed randomized controlled trials on ASD symptomatology did reveal that there was no benefit of oxytocin over placebo and provided further proof to support existing evidence .The Neurochemistry of Autism , 2020
I know from other readings that extracts or refine products often are not as effective as the same chemical “au-natural”. The reason is that the au-natural version have additional chemicals that may work as a catalyst to improve the impact.
In keeping with this approach, I looked for ways of increasing it via the microbiome. This is what I found:
- “Oxytocin (OXT), as a neuropeptide, plays a role in emotional and social behaviors. Lactobacillus reuteri (L. reuteri) supplementation led to an OXT-dependent behavioral improvement in ASD mouse models 
It was previously shown that feeding of a human commensal microbe Lactobacillus reuteri (L. reuteri) is sufficient to up-regulate endogenous oxytocin levels and improve wound healing capacity in mice. Here we show that oral L. reuteri-induced skin wound repair benefits extend to human subjects. Further, dietary supplementation with a sterile lysate of this microbe alone is sufficient to boost systemic oxytocin levels and improve wound repair capacity. Oxytocin-producing cells were found to be increased in the caudal paraventricular nucleus [PVN] of the hypothalamus after feeding of a sterile lysed preparation of L. reuteri, coincident with lowered blood levels of stress hormone corticosterone and more rapid epidermal closure, in mouse models.Microbial Lysate Upregulates Host Oxytocin, 2016
I could not find studies for any other probiotics increasing oxytocin.
I checked Novel and Emerging Treatments for Autism Spectrum Disorders: A Systematic Review (2009) and found L. Reuteri was not listed, so this would be a newer suggestion.
- Grade A treatments for ASD include melatonin, acetylcholinesterase inhibitors, naltrexone, and music therapy.
- Grade B treatments include carnitine, tetrahydrobiopterin, vitamin C, alpha-2 adrenergic agonists, hyperbaric oxygen treatment, immunomodulation and anti-inflammatory treatments, oxytocin, and vision therapy.
- Grade C treatments for ASD include carnosine, multivitamin/mineral complex, piracetam, polyunsaturated fatty acids, vitamin B6/magnesium, elimination diets, chelation, cyproheptadine, famotidine, glutamate antagonists, acupuncture, auditory integration training, massage, and neurofeedback.
It would be nice if someone did an update of these based on the last 11 years of research.