The Adjuvants part is the part in which the potion-maker can become playful, to some extent, something not really recommended for beginner to try. There are certain rules when it comes to the Adjuvants game as well:
1. If the person we are making the potion for is allergic to the active substance, we need to look for another potion with a different active substance but a similar effect. However, if the person is allergic to the base, it is totally okay to switch to a different base, as long as the replacement belongs in the same category. Therefore, oils can be changed for other oils, watery-bases with other watery-bases, fatty bases with other fatty basses (for example, there are people who are allergic to butter, so it is totally fine to switch to cocoa butter for an ointment). When it comes to Adjuvants, they do not have to be replaced. If someone is allergic to an adjuvant, all you have to do is not put it in the potion, and no harm is to happen. For example, many drinkable potions have as adjuvants sugar or honey. If the potion is addressed to a diabetic person, they are either to be replaced with something appropriate or completely left on the side.
2. All research must be done in order to make sure that none of the adjuvants are reactogenic to one another or to the active ingredient or the base. Most common thing that happens when a potion maker fails to do so is to create a very acidic environment in the potion intaker's stomach. The pain lasts for a few hours, then goes away without causing very serious damage. However, we must make sure that, especially drinkable potions are very safe, and that the substances used are not going to cause more harm.
3. Active substances tend to be acids, and base substances tend to be bases. They are calculated in a potion so that they neutralise each other to some extent, to not be very violent. However, after people place 10 acidic adjuvants on top of the mixture, the whole potion can become very acidic, or the other way round, therefore I advise people to always be balanced when placing things of the same nature to work towards the same objective.
4.The main purpose of an adjuvant is to enhance. This is why it is important to be moderate when using them and make sure that not too much is added, as this may completely alter the potions. Too little is better than too much, as if we put too little, we will just not get the enhancement we wanted, but the potion is still good. Whereas if we add too much, may completely destroy it. There are certain exceptions, potions which have more adjuvants than active ingredients/ bases, but that probably happens when the latter 2 are very strong. So it is not always about the quantity, but about how strong a certain substance is. Common sense never fails when it comes to realize which is which and why certain quantities must be respected.
To sum it all up, be very grounded, mature and do your research and think about absolute everything you put in a potion. This way you simply cannot fail. :)