Short answer: there is no established evidence that combining psilocybin with ketamine is safe or effective for PTSD. I cannot verify safety or benefits for this mix.
Mixing psychoactive substances can be unpredictable. Reported risks include intense disorientation, dissociation, nausea, loss of coordination, and a higher chance of accidents. Legality, purity, and dose consistency can also vary, especially with analogs.
If someone is considering this, avoid doing it alone, keep the setting calm and free of hazards, do not mix with alcohol or other drugs, and have a trusted sober sitter. Discuss personal risks and medication interactions with a licensed clinician, particularly if you have PTSD or other mental health conditions.
For community perspectives on this combination, see this discussion: Funky flip or Chonk. Do not treat community reports as medical advice.
Stay safe and take care.