Hi @Reyes, welcome to the forum!
Yes, doubt is fine. If you’re concerned about experiencing slower results, Subconscious Limits Removal is often helpful to play daily, particularly recommended if you are new to morphic fields. Many people play this audio daily as it can help speed up results and dissolve limiting subconscious beliefs which might slow your results.
Here is another morphic field which might be of interest to you, meant to allow most people to experience the effects of a morphic field quickly:
Yes, the Sun Free Tanning audio promotes actual biochemical signals for melanin production and melanocyte-stimulating hormone.
No, the audios do not rely upon your belief to work and do not require belief as a placebo would. Morphic fields which create physical changes will directly alter biochemical factors regardless of your belief.
Believing in changes can increase your receptivity to the morphic fields and aid changes, but it is not required for the changes to occur. One way in which belief might also aid any changes: The nervous system can alter many biochemical signals, depending upon what is prioritised and focused upon. This occurs in each moment of our lives.
So belief can help speed the process of any biochemical changes you wish to make, but it is not necessary and doubt may not necessarily hinder you very much. Doubt and interest in experimenting with the field may actually help you in some ways as you may be more engaged with the process and results.