Starting a sculpt with the goal of hyper realism is quite challenging. It's much more recommended to start with a base mesh. This eliminates the need to find the right proportions, shapes and topology. It's a widely used workflow that saves a lot of time, especially when working on multiple characters.

Free Male Base Mesh

From the Project Heist production we already created a complete male base mesh. You are free to use this for your own projects. You can find it under the CC-By licence here:

Blender File - 14.9 MB - CC-BYrealistic_human_base.blend

This base mesh will be iterated on further and once it's fully done we will make it share it on blender.org more publicly.

Base Mesh Requirements

There are many factors that go into a good base mesh meant as a starting point for any realistic character.

An even quad-only topology.
The topology needs to be optimised for subdivision sculpting via the Multiresolution modifier. This ensures that the level of detail and smoothing strength is predictable and consistent across the model with no/few pinches or stretching while sculpting.

The way we accomplish this is with a relatively even, quad-only topology with as few poles as possible (vertices with more or less and 4 connected edges). This topology does not need to be optimised for rigging & animation, even if it can be used for that.

The topology should also not be too high resolution in the base topology to make it easier to add many subdivisions. Not making the base density too low will also make it easier to reshape the base mesh into many different shapes and proportions (Based on what the character needs to look like).

Add Face Sets.
These help a lot to already set up early on for sculpting. Face Sets are very useful for quickly hiding and masking areas of the object. It can also have a drastic performance boost when less geometry is visible.

Add UV maps.
In the case of early texturing or shading tests during the design process, it's also good to add some simple UV maps, just in case you need them. UDIMs are also great to use to give the head, body and hands their own set of textures.

Strictly use an A- Pose.
This means that the limbs and posture of the body is relaxed, with almost no muscles or surfaces being stretched or compressed. Specifically for realistic characters this is most useful as the resting pose since you can easily add any deformations from there.

Pay attention to the scale.
Giving the base meshes a proper real world scale will save you the hassle of rescaling them later on.