can I apply hydroquinone while having IPL treatment?

Hydroquinone and IPL treatments complement each other well. Hydroquinone bleaches brown pigment. IPL targets red pigment (hemoglobin) and brown pigment (melanin) with heat and destroys the unwanted pigment without affecting the skin or other tissues. Avoid IPL while using retinols or Rx exfoliants. It’s not unusual to find hydroquinone products that contain retinol so check the label(s) prior to IPL treatment.

Hydroquinone is often used together with IPL for treating brown spots.  Sun protection is a must.

Hydroquinone can be used while getting IPL treatments.  In fact, I usually recommend this cream to my patients if we are treating brown spots.  You should not, however, use a retinoid cream (i.e. Retin A, Atralin, Tazorac, Differin, tretinoin) or retinol cream (over the counter retinol containing creams) one week prior to your IPL treatment.  These creams can potentially increase your sensitivity to the IPL treatment and may result in a higher rate of adverse outcomes.  Of course you always also need to wear sunscreen daily (SPF of at least 30).  Best of luck!

Hydroquinone can be applied while having an IPL treatment.  Make sure it is applied in the evening and use
sunscreen in the daytime.

Hydroquinone and IPL are often used in combination. HQ should be applied nightly to dark areas, and you need to be using a good sunscreen daily. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."