Learn Hardcore Portuguese (Portugal): A médica disse que esta vitamina pode ajudar quando estou muito cansado. - The doctor said that this vitamin can help when I am very tired.

A médica = the doctor (female) → we assume the speaker and listener know which doctor they’re talking about (e.g. my doctor, the doctor from the clinic, etc.).
Uma médica = a (female) doctor → introduces a doctor not yet identified/specified.
Bare “médica disse…” (without an article) is not natural here in European Portuguese.

So “A médica disse…” implies a specific, known doctor, which is usually what you mean in this kind of sentence.

Why is it “médica” (feminine) and “cansado” (masculine) in the same sentence? Shouldn’t they match?

They agree with different nouns:

médica agrees with the implied noun a mulher / a senhora (the woman / the lady) → a médica = female doctor.
cansado agrees with the subject eu (I).

So if I am male:

estou muito cansado → I (male) am very tired.

If the speaker is female, it should be:

A médica disse que esta vitamina pode ajudar quando estou muito cansada.

The adjective cansado/cansada always agrees with the person who is tired, not with médica.

Why is the verb “disse” used here, and what tense is it?

Disse is the pretérito perfeito (simple past) of dizer (to say):

eu disse – I said
tu disseste – you said
ele/ela disse – he/she said

Here, A médica disse… = The (female) doctor said…, a completed action in the past. That’s exactly what the English past tense “said” does.

Could I say “falou que esta vitamina pode ajudar” instead of “disse que…”?

In European Portuguese, dizer is the default verb for reported speech (“say that…”):

A médica disse que… is perfectly standard and the most natural option.

You can hear falar used like this in some contexts, but:

In Portugal, falar is more “to speak / to talk (about something)”:
- A médica falou sobre vitaminas. – The doctor talked about vitamins.
In Brazil, falar que as “say that” is much more common and informal.

So for European Portuguese learners, it’s safest and most natural to stick with “A médica disse que…” for “The doctor said that…”.

Why do we need “que” after “disse”? Can I just say “A médica disse esta vitamina pode ajudar”?

No, in standard Portuguese you need que to introduce the subordinate clause:

A médica disse que esta vitamina pode ajudar…
= The doctor said *that this vitamin can help…*

Que here is a conjunction “that”, just like English “that” in “She said that…”.
Dropping que in this sentence is ungrammatical in careful speech and writing.

Why is it “pode ajudar” and not something like “pode a ajudar” or “pode te ajudar”?

The structure here is:

pode – present tense of poder (can / may).
ajudar – infinitive to help.

Together: pode ajudar = can help.

A few notes:

No preposition is needed before the infinitive here:
- pode ajudar (can help)
- But if you add another verb, you might get ajudar a + infinitive:
  - pode ajudar a recuperar energia – can help to recover energy.
There is no explicit object:
- It means “can help (me / you / in general)” from context.
- If you make it explicit:
  - pode ajudar-me (EP formal/neutral)
  - pode ajudar-me quando estou muito cansado – can help me when I am very tired.

Why is it “esta vitamina” and not “essa vitamina” or just “a vitamina”?

Portuguese has three main demonstratives:

esta – this (close to the speaker)
essa – that (close to the listener, or already mentioned)
aquela – that (over there) / more distant

In practice, especially in European Portuguese:

esta vitamina suggests “this vitamin (here)” or “this one we’re talking about right now”.
essa vitamina is usually “that vitamin (you mentioned / near you)”.
a vitamina is just “the vitamin”, with no focus on distance; it could also work if the specific vitamin is already known.

All three might be possible depending on context, but esta is used if the speaker is highlighting this particular vitamin as the one being referred to now.

Why is it “quando estou muito cansado” and not “quando eu estou muito cansado”?

Portuguese is a pro-drop language: you often omit the subject pronoun because the verb ending already shows the subject.

estou can only be eu (I), so eu is not needed:
- (Eu) estou muito cansado.

You can say “quando eu estou muito cansado” if you want to emphasize I in contrast to others:

Quando eu estou muito cansado, não saio de casa.
(Me, when I’m very tired, I don’t go out.)

But the neutral, everyday version is with no pronoun:
quando estou muito cansado.

Why is it indicative (“quando estou”) and not subjunctive, like “quando estiver”?

With quando, Portuguese normally uses:

Indicative (e.g. estou) for habitual, factual, or repeated situations:
- quando estou muito cansado – whenever I am very tired (a regular pattern).
Future subjunctive (e.g. estiver) for future, not-yet-realised situations:
- Quando estiver muito cansado, vou descansar. – When I am tired (in the future), I’ll rest.

In your sentence, the doctor is talking about a general, repeated situation:
“when I’m (ever) very tired, this can help”.
So indicative (estou) is correct and natural.

Why is it “estou muito cansado” and not “sou muito cansado”?

Portuguese distinguishes ser and estar:

estar = temporary state or condition:
- estou cansado – I’m tired (right now / at that time).
ser = more permanent, inherent characteristic:
- sou cansativo – I am tiring / I’m a tiring person (a personality trait).
- sou preguiçoso – I’m lazy (as a characteristic).

Feeling tired is a temporary condition, so you use estar:
estou muito cansado.

Why is it “muito cansado” and not “cansado muito”?

In Portuguese, intensifying adverbs like muito (very) usually come before the adjective they modify:

muito cansado – very tired
muito feliz – very happy
muito importante – very important

“cansado muito” is not natural here. Word-for-word English order doesn’t work; keep muito before the adjective.

How would I show clearly that the vitamin helps me, personally?

You can add a clitic pronoun for the object me:

A médica disse que esta vitamina me pode ajudar quando estou muito cansado.
A médica disse que esta vitamina pode ajudar-me quando estou muito cansado.

Both are correct in European Portuguese:

me pode ajudar – pronoun before the verb (more common in speech).
pode ajudar-me – pronoun after the infinitive, with hyphen (very standard, often preferred in writing).

In everyday speech in Portugal, people might more naturally say:

A médica disse que esta vitamina me pode ajudar quando estou muito cansado.

How is this sentence pronounced in European Portuguese?

Approximate IPA (European Portuguese):

A médica disse que esta vitamina pode ajudar quando estou muito cansado.
/ɐ ˈmɛdʲikɐ ˈdisɨ kɨ ˈɛʃtɐ vitɐˈminɐ ˈpɔðɨ ɐʒuˈðaɾ ˈkwɐ̃du ɨʃˈto muˈitu kɐ̃ˈsadu/

Some key points:

A → [ɐ], a very short, unstressed “uh”.
médica → mé stressed: MÉ-di-cɐ.
disse → DI-sse, final e is reduced: [ˈdisɨ].
que → often [kɨ], very short.
esta → [ˈɛʃtɐ], s before t sounds like sh.
vitamina → vi-tɐ-MI-nɐ (stress on mi).
pode → [ˈpɔðɨ], d sounds soft between vowels.
ajudar → [ɐʒuˈðaɾ], j like French/English “measure”.
quando → [ˈkwɐ̃du].
estou → [ɨʃˈto], with that typical European sh sound before t.
cansado → [kɐ̃ˈsadu], final o often sounds like u.

You don’t need to master the IPA, but knowing that many unstressed vowels reduce to a short “uh” [ɐ]/[ɨ] and that s before consonants often sounds like sh [ʃ] is very helpful for sounding more European Portuguese.