Short answer. No. The Revised Penal Code is explicit: no penalty shall be executed except by virtue of a final judgment. Until the judgment against you has become final, the sentence cannot be enforced against you, and it can only be carried out in the form the law prescribes.
What the law says
No penalty shall be executed except by virtue of a final judgment. A penalty shall not be executed in any other form than that prescribed by law, nor with any other circumstances or incidents than those expressly authorized thereby.
Revised Penal Code, Article 78 — How A Penalty Is Executed. Read the full provision →
Finality first, punishment after
Article 78 opens with a flat guarantee: no penalty shall be executed except by virtue of a final judgment. A conviction that is still open to appeal, or whose period to appeal has not yet run out, is not a final judgment. Until that point is reached, the State cannot carry the sentence into effect. This is why a person can be convicted by a trial court yet not begin serving the penalty imposed while the case is still moving through the appellate stage. The rule reflects the presumption that a judgment is not truly settled until the courts are done with it.
Detention is not the same as executing a penalty
It is important not to confuse two different things. Being held in jail while a case is pending — because bail was denied or not posted — is detention connected to the prosecution, not the execution of a penalty. Executing the penalty means enforcing the specific punishment the judgment imposes, and that is what Article 78 forbids before finality. So a person may lawfully be detained during trial and appeal without that detention being the sentence itself. The distinction matters, because time spent in that kind of confinement is treated differently from serving the penalty after judgment.
The penalty must follow the prescribed form
Finality is only the first limit. The article adds that a penalty shall not be executed in any other form than that prescribed by law, nor with any other circumstances or incidents than those expressly authorized thereby. The authorities cannot invent a harsher or different mode of carrying out a sentence than the law allows. The provision then points to the special regulations governing the institutions where penalties are served — covering the work required, the separation of the sexes, relief, diet, and the correction and reform of convicts. Punishment is confined to what the law and those regulations authorize, nothing added on.
If a sentence is being enforced early
If you believe a penalty is being carried out against you before the judgment is final, the decisive questions are whether the judgment has in fact become final and whether what is happening is execution of the penalty or lawful detention during the case. The dates — when the decision was promulgated, whether an appeal was taken, and when any period to appeal lapsed — are what settle it. These are technical points that turn on the record of your specific case, so the exact procedural history should be reviewed carefully rather than assumed.