Hello sir, if it is a non-volatile active, it can be masked with an inert odour masking agent and then used, and if its a volatile principle, additional fragrances can be added to the cream/lotion.
Thanks a lot to Mercedes, Irina and Harita. Probably I will consider 2 approaches based on your suggestions: 1. Encapsulating the component conferring bad smell, & 2. Adding another component with a good smell to neutralize unpleasant odor.
Remember that encapsulation can change the skin bioavailability of your smelling compound. Of course, in good way sometimes - decreasing irritation potential or forming a depot on the skin surface.
If your active compound has a bad smell, it means it is volatile, what would be the shelf-life of the product that has this ingredient in it? Is there any solvent (or emulsifier) that can localize your volatile ingredient in the bulk of the mix? The bottom line is you have to include this ingredient in a relatively stable cluster or micelle of some kind.
In fact you have to encapsulate that active of formulation, no other choice than this because masking the odor with perfumes may arise some other problems like skin irritation etc. In fact any perfume has thousands of constituents which may destabilize your formulation and illicit some skin sensitivity response.