Sun in the 1st house (Tanu / Lagna, the house of self) brings the significations of Sun, namely soul (atma), father, authority & government, into the area of the self, body and the lens through which the whole chart is read. The 1st house governs self & personality, physical body & appearance, health & vitality, temperament.
Results of Sun in the 1st House
Sun is a malefic planet, so here it tends to bring low confidence, ego conflicts, trouble with father or bosses, and weak vitality focused on the self, body and the lens through which the whole chart is read. As an angular (kendra) house, this placement strongly shapes the overall life direction. As a trine (trikona) house of fortune, benefic influence here is especially auspicious.The exact result depends on which sign Sun occupies here and the aspects it receives.
When It Activates
These results typically surface during the Vimshottari mahadasha or antardasha of Sun, and when transiting planets trigger the 1st house. A well-placed Sun here supports good health, a strong personality, confidence and a clear life direction; when afflicted it can indicate poor health, low self-image and a life that feels directionless.