I agree Anna. There is this research article that studies 4% hydroquinone and 5% l-ascorbic acid for melasma. I have pasted the abstract below:
"
BACKGROUND: Melasma is an acquired treatment-resistant hyperpigmentation of the skin.
METHODS: Sixteen women with idiopathic melasma were included in our trial. After randomization by another clinician, they were instructed to use, at night, 5% ascorbic acid cream on one side of the face and 4% hydroquinone cream on the other side, for 16 weeks. Sunscreen was applied daily throughout the period of observation. They were evaluated every month by colorimetry, digital photography, and regular color slides. Subjective evaluation by each patient was also taken into account.
RESULTS: The best subjective improvement was observed on the hydroquinone side with 93% good and excellent results, compared with 62.5% on the ascorbic acid side (P < 0.05); however, colorimetric measures showed no statistical differences. Side-effects were present in 68.7% (11/16) with hydroquinone vs. 6.2% (1/16) with ascorbic acid.
CONCLUSION: Although hydroquinone showed a better response, ascorbic acid may play a role in the therapy of melasma as it is almost devoid of side-effects; it could be used alone or in combination therapy." (
LINK)
This is a well done study because it is randomized and double blinded. The abstract says nothing about placebo, but that's just one factor (but it would have been nice to add that component in). I wish there were more volunteers. I'd like to note that it was
JUST 5% l-ascorbic acid verse
PERSCRIPTIONS STRENGTH hydroquinone. What if it was 10% L-ascorbic acid? 15%? 20% (supposedly the max you can go)? How about vs 2% or 1% hydroquinone, which is over the counter? Well, at least Vitamin C does help eve in low strength, we can infer that it
MAY help with higher concentration.
[Update: Oh wait, one more thing, on the Obagi website, the doc post up before and after for one of this product systems which contain 4% hydroquinone and vitamin C (10%) -
LINK TO PICTURE. You have to click on the "Before & After" tab on the right. Yes I am aware there might be a conflict of interest on Dr. Obagi's part, but I am willing to say he is not lying about this, the research is clear.]