It is important to understand that these are global transit energies, which must always be carefully nuanced according to your birth chart. See the article Mercury in transit for a general approach; for the interpretation of your natal Mercury, refer to Mercury in signs.
This is a fast transit (around twenty days on average, excluding retrograde periods), closely accompanying our daily life and exerting a constant influence on the mind, intuition, logic, and rational thinking.
Mercury is generally considered a “neutral” planet, although it is often associated with the Logos of the Animus within the chart; in this sense, it can indicate a projection of it.
It also frequently provides information about siblings, close relatives, the immediate environment, friends, neighbors, and clients, expressing qualities that take on the tone and coloration of the sign it occupies.
Heightened mental and intellectual activity
When Mercury transits Aries or the 1st House, thinking becomes more directly focused on projects related to personal fulfillment and self-assertion.
It is a more action-oriented period of “materialization”, testing, implementation, and self-expression.
Here, with Mercury under the direct rulership of Mars, this can also lead to reassessing one’s appearance, changing one’s look, returning to sport, starting a diet, anything that can be broadly useful to initiate change and set a new dynamic in motion.
The intellect becomes more effervescent, the mind runs at full speed: ideas and intuitions abound, along with a stronger desire to communicate, exchange, and invest socially, often in a light, eloquent, and playful way.
This can also be useful for giving advice and making oneself clearly understood, putting one’s ideas forward, asserting them, speaking publicly, and being heard.
There may also be a thirst for knowledge and learning of all kinds, greater curiosity, and sharper mental acuity than usual.
Any work requiring mental engagement will be favored, such as writing, reading, calculating, organizing, or handling concepts and theories, as well as engaging in brainstorming sessions at work or with others.
This can also be a time to reconnect “with one’s siblings”, for example, to develop relationships with neighbors, or to make contact with one’s clientele.
The key point to understand here is above all the notion of boldness: initiating things.
This is not a time to wait passively for others to propose or invite, but rather to take the lead yourself, to step forward and be the one who proposes or invites others.
On the challenging side, this mental agitation can lead to over-intellectualizing everything, increasing nervousness without necessarily finding a concrete outlet. The risk of dispersion is greater (starting several things at once and finishing none), and it can become difficult to truly relax.
In this sense, it may be helpful to consciously support and balance these forces, and to find ways to release the pressure.
In certain cases, this may also manifest as an argument or a conflict, especially if the planet is under tension, whether in the birth chart or through other transiting influences.
That said, there are clearly the means here to assert one’s arguments and be heard: this is not about suffering in silence, but about expressing what lies on one’s heart.
A retrograde Mercury in the 1st House or in Aries therefore tends to prompt a reassessment of the way one asserts oneself personally.
The planet insists by forcing us to reposition ourselves on certain issues.
This concerns both what you project outward and what you intend to do.
The retrograde motion increases the time available to carry out these changes. There may be delays or setbacks, compelling you to re-examine yourself and to draw the necessary conclusions regarding your initiatives.
Ultimately, the aim of the retrograde motion is still to increase self-confidence, to develop greater charisma, in short, to explore more deeply a “personal issue” and to help it evolve accordingly.