Hi,
A logical question, but the answer may not be so straight forward. Skin lightening creams work by reducing the amount of melanin in the skin.
A lightening cream may have several mechanisms of action resulting in a decrease in melanin production and/or deposition in the skin cells. The different mechanisms of action include:
1) Inhibiting the activity of tyrosinase e.g. hydroquinone (a major ingredient of Tri-Luma), cysteamine, arbutin, koljic acid, azelaic acid.
2) Preventing tyrosinase from being activated to its functional form e.g. tretinoin (a major component of Tri-Luma), cysteamine.
3) Removing the intermediate products of melanin synthesis.
4) Preventing the transfer of melanin to the surrounding skin cells e.g. niacinamide
5) Removing existing melanin e.g. tretinoin (a major component of Tri-Luma), exfoliating agents
6) Regulation of melanocytes environment e.g. corticosteroid (a major component of Tri-Luma)
7) Antioxidants e.g. vitamin C
Combining different lightening components may give a better effect if they target different parts of the pigment forming and deposition process e.g. the three major ingredients of Tri-Luma, hence augmenting the lightening capability of individual components.
On the other hand, if already one cream is very effective, adding another and/or several more may not give additional significant benefits and will certainly increase costs and may even increase skin irritation. Here, the expertise of your doctor will be useful to guide you in selecting the appropriate combination of lightening creams based on the severity of your pigmentation and skin type in order to strike a balance between added benefits, unwanted side-effects, and value.
Hope this helps!
