I am a Doctor planning to open a clinic with the following services. Each service Halal or not:
1) Hair transplant for bald people.
2) Hair removal for men and women.
3) Wrinkles removed from faces by injections?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

1) According to the Islamic Law, hair transplantation is permissible.  This is not considered the same as joining the hair that is forbidden in a Prophetic narration.  The Prophet, sallallaahu ‘alayhi wa sallam, said: ''Allaah has cursed the woman who joins the hair and the woman to whom the hair is joined…" [Al-Bukhari and Muslim]

This is not considered as changing Allaah's Creation because it is bringing back what Allaah has created. It is regarded as permissible treatment because it is transplanting the hair in its right place.  The evidence for this is the narration of 'Arfajah ibn Sa’d   who said: ''My nose was cut off on the day of Al-Kulaab, and I transplanted a silver nose, but it developed a stench, then the Prophet, sallallaahu ‘alayhi wa sallam,  ordered me to transplant a golden nose." [Abu Daawood].

2) The hair on a human’s body is of three types:

The first type:  The hair which Allaah forbade us from removing, like men shaving the beard and like plucking the eyebrows (and this applies to both men and women).  The evidence for the prohibition of shaving the beard is that the Prophet, sallallaahu ‘alayhi wa sallam, forbade us from doing so, as Ibn ‘Umar narrated that the the Prophet said: ''Trim your moustache and let your beards grow freely.''  [Muslim]

As regards the evidence for the prohibition of removing the hair of the eyebrows, Ibn Mas'ood said: ''The Prophet, sallallaahu ‘alayhi wa sallam, cursed those ladies who practice tattooing and those who get themselves tattooed, and those ladies who remove the hair from their eyebrows and those who make artificial spaces between their teeth in order to look more beautiful whereby they change Allaah's Creation". His (Ibn Mas’ood’s) saying reached a lady who came to him and said: ''I have come to know that you have cursed such-and-such (ladies)?" He replied: "Why should I not curse those whom the Prophet, sallallaahu ‘alayhi wa sallam, cursed and who are (cursed) in Allaah's Book! "Allaah Says (what means): {…And whatever the Messenger has given you, take it, and what he has forbidden you, abstain from …} [Quran 59:7]. [Al-Bukhari and Muslim]

The evidence from the narration is the Arabic word "Al-Mutanammisah" which is interpreted by the scholars to mean "removing the hair of the eyebrows in order to make them thin.''

The second type:  The hair which Allaah instructed us to remove, like the hair of the armpit and the pubic hair, and the trimming of the moustache.  The evidence for this is that Abu Hurayrah  narrated that the Prophet said: "Five are among the Fitrah acts (i.e. natural disposition upon which Allaah created mankind): Circumcision, shaving the pubic hair, plucking out the armpit hair, clipping one's nails and trimming one's moustache." [Al-Bukhari and Muslim].

The third type:  The hair about which no text has been reported regarding removing it or leaving it, like the hair of the chest, the hair at the back of the body and the hair of the thighs and legs.  There is no text which orders us to remove or to leave such type of hair.  So it is up to the person’s choice whether to leave it or to remove it.

Therefore, it is permissible for men and women to remove the hair which is desirable to remove on the condition that one should not show what is not permissible  to reveal (his ‘Awrah’ i.e. parts of the body that must be covered in Islam).

3) It is permissible to use collagen and Botox injections to remove the wrinkles on the face, as long as that does not cause any harm either in the short run or the long run, as the Prophet, sallallaahu ‘alayhi wa sallam, said: “There should be no harm and no reciprocal harm.” [Abu Daawood]

Allaah Knows best.