Hairdressers recommend waiting for 48 hours before washing permed hair to avoid loosening the curls, which results in less curly and weaker hair. Tying or brushing newly permed hair within the stated waiting time is also avoided for that same reason.
However, some disagree with this as the neutralizer applied at the post-perm stage is intended to preserve the degree of perm. If the neutralizing lotion is applied and allowed to stay on for 10 to 20 minutes, the perm should be set for good.
If loosening occurs, it is observed within the two-day waiting time, even if the newly permed hair was washed.