Cuando voy al gimnasio, llevo el gel para ducharme después de entrenar.

Because this sentence describes a habitual action: Whenever I go to the gym, I take the shower gel...

In Spanish, the present tense is very often used for routines and repeated actions:

• Cuando voy al gimnasio, llevo... = When/Whenever I go to the gym, I take...

Using iré would refer to the future (I will go), which does not fit this general, repeated meaning.

Cuando without an accent is used in statements, connectors, and subordinate clauses:

• Cuando voy al gimnasio... = When/Whenever I go to the gym...

Cuándo with an accent is used in direct or indirect questions:

• ¿Cuándo vas al gimnasio? = When do you go to the gym?
• No sé cuándo va al gimnasio. = I don’t know when he/she goes to the gym.

So here, because it means when/whenever in a normal statement, it is cuando.

Because a + el contracts to al in Spanish.

So:

• voy a el gimnasio ❌
• voy al gimnasio ✅

This contraction is required almost all the time.

A similar contraction happens with de + el = del:

• vengo del gimnasio = I come from the gym

Here llevo means I take / I bring with me / I carry.

The verb llevar often means to carry or take along something from one place to another.

So in this sentence:

• llevo el gel = I take the shower gel with me

A learner may confuse llevar and traer:

• llevar = to take, to carry away / along
• traer = to bring (toward the speaker or destination)

In this context, llevar is the natural choice because you are taking the gel with you to the gym.

In Spain, gel often means shower gel / body wash, especially in everyday speech.

So:

• el gel can mean shower gel
• Sometimes people say gel de ducha more explicitly

In this sentence, el gel para ducharme clearly means the gel used for showering.

The article el is used because it refers to a specific item or type of product the speaker normally takes.

Because with an infinitive, object and reflexive pronouns are usually attached to the end.

So:

• ducharme = to shower myself / to have a shower
• para ducharme = in order to shower

Para me duchar is not correct standard Spanish.

This pattern is very common:

• quiero ducharme = I want to shower
• voy a ducharme = I’m going to shower
• necesito cambiarme = I need to get changed

In Spanish, ducharse is commonly used as a reflexive verb to mean to have a shower / to shower oneself.

So:

• duchar = to shower someone/something
• ducharse = to shower oneself

Examples:

• Voy a duchar al niño. = I’m going to shower the child.
• Voy a ducharme. = I’m going to shower.

In your sentence, ducharme means to shower myself / to have a shower after training.

Because entrenar here is being used in a non-reflexive way: to train / to work out.

So:

• después de entrenar = after training / after working out

In many contexts, entrenar is perfectly natural without a reflexive pronoun.

You may also hear entrenarse, but in this sentence entrenar is the simpler and more natural option.

Also remember the structure:

• después de + infinitive

Examples:

• después de comer = after eating
• después de trabajar = after working
• después de entrenar = after training

Because in Spanish, when después is followed by an infinitive or a noun, it normally takes de:

• después de entrenar = after training
• después de la clase = after class

So después entrenar would be incorrect.

This is just a fixed structure you need to learn:

• antes de... = before...
• después de... = after...

Usually, llevo is better here.

Why?

Because from the speaker’s point of view, they are taking the gel with them to the gym. That idea is expressed by llevar.

• llevar = to take along
• traer = to bring here / toward a place seen as the destination

In many everyday situations, English speakers overuse bring and try to map it directly onto Spanish. In this sentence, standard Spanish prefers llevo.

In this sentence, it often feels closer to whenever in English, because it describes a repeated habit:

• Cuando voy al gimnasio, llevo el gel...
• Whenever I go to the gym, I take the shower gel...

But when I go to the gym is also a natural translation in English, depending on context.

So the Spanish can cover both ideas:

• a routine
• a repeated situation

Yes, you could, but the meaning changes slightly.

• llevo el gel suggests the shower gel / my shower gel / the specific gel I use
• llevo gel sounds more general: I take shower gel

Both are possible, but el gel sounds very natural if you are talking about the usual item you take with you.

Para here means for or in order to. It introduces the purpose of taking the gel.

So:

• llevo el gel para ducharme = I take the shower gel to shower / in order to shower

This is a very common structure:

• Estudio para aprender. = I study in order to learn.
• Llevo agua para beber. = I take water to drink.
• Traigo ropa para cambiarme. = I bring clothes to get changed.

Yes, Spanish has some flexibility, although the original sentence is very natural.

For example, you could also say:

• Cuando voy al gimnasio, llevo el gel para ducharme después de entrenar.
• Llevo el gel para ducharme después de entrenar cuando voy al gimnasio.

The first version is better because it presents the context first (when I go to the gym) and then the main action.

Spanish word order is often flexible, but the most natural order is usually the one that sounds clearest and most balanced.

It works in both Spain and Latin America, but gel meaning shower gel/body wash is especially common in Spain.

In other Spanish-speaking countries, people might also say things like:

• jabón
• gel de baño
• gel de ducha

But the grammar of the sentence is completely standard across Spanish.