The invention relates to cell-free supernatants (conditioned media) that previously supported the growth of a dedifferentiated plant cell suspension culture, or a fraction of said cell-free supernatant, said cell-free supernatant or said fraction comprising peptides from 4 to 300 amino acids length and including peptide plant growth factors and peptide plant transcription factors, and without having cytoplasmic cell contents from the cell lysis and membranes and/or cell walls. The invention also relates to fractions of said supernatants and to cosmetic applications for promoting re-youth of skin.