After photodynamic therapy, how long does the skin's purging process last?

Doctor Answers 3

After Photodynamic Therapy (PDT) How Long Til Results? - Wait 4 to 8 Weeks

PhotoDynamic Therapy (PDT) uses four different wavelengths of lasers (PDL, IPL, red light and blue light) to target lesions and irregularities on the skin. It can be used to improve or resolve issues such as:

  • Aged or irregular skin
  • Acne
  • Actinic keratosis (precancerous lesions)
  • Hyperactive oil glands
  • Hyper- and hypo-pigmentation

Depending on your metabolism, it will take approximately 4 to 8 weeks before the old skin is completely eliminated and the new layers of improved skin can be seen. Please wait about two months before deciding if you need another treatment. Finding a board-certified dermatologist who is expert at resurfacing the skin with PDT will help answer any questions you have and determine if you are a candidate for PDT.

San Diego Dermatologist
4.8 out of 5 stars 46 reviews


Good question .It takes up to 4 weeks to see a result after a first treatment with PDT. A second treatment may be necessary in order to achieve the best results.

Joseph Doumit, MD
Montreal Dermatologist
5.0 out of 5 stars 4 reviews


It takes the skin 28 days on average to go through a full skin cycle.  It usually takes 2 full skin cycles to see great changes in the skin.  It is for this reason that most people wait 8 weeks to see the full benefit from a treatment of PDT.  We often will treat people with 2 treatments of PDT spaced 8 weeks apart.  We see great results with this treatment.  Stay skintastic.  

Sandra M. Johnson, MD
Fort Smith Dermatologist
5.0 out of 5 stars 5 reviews

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.