Learn Hardcore Romanian: Eu sunt deja relaxat, pentru că medicamentul ajută. - I am already relaxed because the medicine helps.

Eu sunt deja relaxat – the most neutral and natural.
Eu deja sunt relaxat – more emphasis on deja (already), often in contrast:
- Eu deja sunt relaxat, voi abia începeți.
Eu sunt relaxat deja – possible, but sounds more informal / expressive; it often comes with intonation stressing deja.

All are grammatically correct, but Eu sunt deja relaxat is the safest, most standard choice.

Why is it relaxat and not something like relaxată?

Relaxat / relaxată is an adjective that agrees with the gender and number of the subject:

masculine singular: relaxat
feminine singular: relaxată
masculine/mixed plural: relaxați
feminine plural: relaxate

So:

A man: Eu sunt deja relaxat.
A woman: Eu sunt deja relaxată.
A group of men / mixed group: Noi suntem deja relaxați.
A group of women: Noi suntem deja relaxate.

In your sentence, relaxat assumes the speaker is grammatically masculine.

What is the difference between sunt relaxat and m-am relaxat?

Sunt relaxat = I am relaxed (a state, how you are now)
M-am relaxat = I relaxed / I have relaxed (an action that happened)

Your sentence:

Eu sunt deja relaxat, pentru că medicamentul ajută.
focuses on the result/state: I am (already) in a relaxed state.

If you wanted to emphasize the action of becoming relaxed, you’d say:

M-am relaxat deja, pentru că medicamentul ajută. – I’ve already relaxed…

Why is there a comma before pentru că?

In Romanian, you normally put a comma before pentru că when it introduces a reason clause (like because in English):

Eu sunt deja relaxat, pentru că medicamentul ajută.

The main clause is Eu sunt deja relaxat, and the reason clause is pentru că medicamentul ajută.
Romanian punctuation rules usually require a comma between these two clauses, just like English often does before because (though English is more flexible).

What does pentru că literally mean, and how is it different from just că?

Literally:

pentru = for
că = that

Together, pentru că functions as a unit meaning because.

Că by itself usually means that (introducing a clause):

Știu că medicamentul ajută. – I know that the medicine helps.

You generally cannot just replace pentru că with că when you mean because:

Eu sunt deja relaxat, că medicamentul ajută. – sounds wrong/odd in standard Romanian.

Other common alternatives for because:

deoarece – more formal: Sunt relaxat, deoarece medicamentul ajută.
fiindcă – quite common: Sunt relaxat, fiindcă medicamentul ajută.

Why is it medicamentul and not just medicament?

Romanian uses a definite article attached to the end of the noun:

medicament – medicine / a medicine
medicamentul – the medicine

So medicamentul is medicament + ul (= the).

In English you say the medicine helps; Romanian mirrors that with the definite form:

medicamentul ajută. – the medicine helps.

Using just medicament ajută would sound incomplete or unnatural in this context, as if you were talking about medicine in general in a very abstract way; even then, speakers would usually still use the definite form.

What does ajută correspond to in English grammar?

Ajută is the 3rd person singular, present tense of the verb a ajuta (to help).

Conjugation in the present (short version):

(eu) ajut – I help
(tu) ajuți – you help
(el/ea) ajută – he/she helps
(noi) ajutăm – we help
(voi) ajutați – you (pl.) help
(ei/ele) ajută – they help

So medicamentul ajută = the medicine helps (present simple).

Should it be medicamentul mă ajută (the medicine helps me) instead of medicamentul ajută?

Both are possible, but they don’t say exactly the same thing:

Medicamentul ajută. – The medicine helps (it is effective / it works).
- More general: you’re stating that the medicine is helpful, without saying whom it helps.
Medicamentul mă ajută. – The medicine helps me.
- Focuses specifically on you as the one who benefits.

Your sentence is:

Eu sunt deja relaxat, pentru că medicamentul ajută.
Here the meaning is clear from context: the medicine works (for me), so I am already relaxed.

Is deja always placed before the verb, like in sunt deja?

Not always, but that is a very common and neutral position.

You can put deja in a few places:

Eu sunt deja relaxat. – very natural.
Eu deja sunt relaxat. – emphasizes already a bit more.
Eu sunt relaxat deja. – also possible; more informal / expressive.

In most cases, placing deja before the adjective or directly after sunt sounds the most natural:

Sunt deja obosit. – I am already tired.
Este deja târziu. – It is already late.

Is there any difference between sunt and sînt?

They are two spellings of the same word, pronounced the same way.

sunt – the official modern spelling
sînt – an older spelling that some people still prefer for stylistic or ideological reasons

Both mean I am or they are (depending on context):

Eu sunt / sînt – I am
Ei sunt / sînt – they are

In standard contemporary writing, sunt is what you’ll usually see and what you should use as a learner.

Does pentru că require the subjunctive, or do we just use the normal (indicative) form like ajută?

After pentru că, Romanian normally uses the indicative (the “normal” verb form):

… pentru că medicamentul ajută. – indicative, present
… pentru că sunt obosit. – indicative

You would not normally use the subjunctive here.
So your sentence is correctly using ajută in the indicative.

Could I say Eu sunt deja calm instead of Eu sunt deja relaxat?

Yes, but there is a nuance difference:

relaxat – relaxed (physically/mentally at ease, as after a massage or medicine)
calm – calm (not agitated, more about emotional state / temperament)

With medicine, relaxat feels more directly connected to muscle/mental relaxation.
Calm would focus more on not being nervous or upset:

Eu sunt deja calm, pentru că medicamentul ajută. – The medicine makes me calm (not anxious).
Eu sunt deja relaxat, pentru că medicamentul ajută. – The medicine has relaxed me / put me at ease.

Both are correct; which you choose depends on the exact nuance you want.