Hair and Makeup is primarily a female aspect to headshots.  But men, always bring translucent powder, shine blotting paper and cherry Chapstick. The cherry Chapstick is brand specific.  It has a slight amount of color and no shine so you don't look like you are wearing lipgloss or lip stick but handles the ashiness or colorless thing that often happens for mens photoshoots.  This is such an important tool for men that I tell every male client I have to always use that before a photoshoot and before an audition.  When you go into an audition casting usually records your audition.  Its one small thing to help you for camera gentlemen.  For men with skin issues, you should look into hiring a makeup artist for your shoot.

For women make up and hair is a part of headshots decisions you need to make and weight out with your budget.  It can dramatically increase your cost, but it can be worth it.  Most women know the range of makeup needed for their headshots.  You aren't doing crazy makeup.  You start off fresh clean and simple and work your way to more dramatic, if that is a part of your casting.   But it takes energy and rushes you personally in the photoshoot.  About half my clients come with their clean fresh faced light makeup and they personally build up through their casting.  The other half hire professional makeup artist.  When you are doing that you should arrive fresh faced giving your makeup artist a clean slate.

Most people who are hiring a makeup artist will strive to find someone that does both hair and makeup and can extend the length of time of your shoot.  Even if you are hiring a hair stylist or a makeup artist that can do hair, you need to arrive with your hair ready for the first look. This saves massive time.  But if you can afford both hair and makeup, I do recommend doing both because it saves you time and allows for more shots to be taken.  

If you are not hiring a hairstylist, and even if you do, you need to bring a brush, comb, hair products, hair ties and clips, bobbie pins and hair products that handle fly aways.

African American women face a completely different challenge on hair as they are trying to cover their casting. I have had women show up with wigs to help with accomplishing different looks, but only one ever came with high quality wigs.  The rest always looked better with their natural hair. I started working out a package for African American women, and women with naturally tight ringlet curls.  It takes time even to manage the natural curls, much less straightening your hair.  So ask your photographer if they are willing to do a split session with you.  I worked it out so I did half the shoot one day and the other half within 3 days from the first shoot.  Do one with natural curl and the other straightened out.  I charge 20% more for this because you are getting two photoshoots to cover your casting.  But all women I have done this with also did their own makeup because makeup artists can't do two separate days and pay their bills and paying twice as much for makeup is hard on the budget for most actors.  But if you don't have great quality wigs this is a better option than wigs that just don't look right.  Also, if you are not particularly good at managing your natural curl set up your photoshoot allowing you time to go to a proper salon that specializes in curl.  You want your hair to be wonderful.