Kligman’s formula
Kligman and Willis used a combination regimen of 5% HQ, 0.1% tretinoin, and 0.1% dexamethasone in a hydrophilic ointment and demonstrated an efficacy in the treatment of melasma, ephelides, and postinflammatory hyperpigmentation.[29] In this formula, tretinoin functions as an irritant to facilitate epidermal penetration of HQ, and it also plays an antioxidative role to prevent oxidation of HQ. Dexamethasone, on the other hand, is used to decrease the irritation caused by HQ or tretinoin and to inhibit melanin synthesis by decreasing cellular metabolic activity. Depigmentation occurs rapidly beginning within 3 weeks after twice-daily application of the formula and maximizing in 5 to 7 weeks.
Pathak’s formula
Pathak and colleagues conducted a clinical trial of this formula on 300 Hispanic women with melasma and showed superior results with creams or lotions that contained 2% HQ and 0.05–0.1% tretinoin.[5] The authors suggested that topical steroids are not necessary to achieve rapid clearance and that they should be preserved for patients who suffer irritation from tretinoin or HQ.
Westerhof’s formula
The combination of 4.7% N-acetylcystein (NAC), 2% HQ, and 0.1% triamcinolone acetonide improved melasma after 4 to 8 weeks of application in a left–right, placebo-controlled clinical study of 12 female patients.[40] The bleaching effect of NAC probably relates to the increase of intracellular glutathion that stimulates pheomelanin rather than eumelanin synthesis after binding with dopaquinone, clinically producing a lighter pigment. As sulfur-containing moeties, NAC and glutathion exert an inhibitory effect on tyrosinase, which may also account for their bleaching properties.
From:
ScienceDirect - Clinics in Dermatology : Depigmenting and bleaching agents: coping with hyperpigmentation
I would suggest combining some of these things in your mixture, or at the very least taking them orally. Don't just try one product try several (soap, cream, lotion, gel, pills, exfoliate, etc) and research. I have been tracking the effects of NAC, MSM, and pycnogenol taken orally. Also, be realistic and don't expect to get results overnight.