How to help an adult that has grown up, but was unloved by their parents? Is there anything that can be done to support a person that was raised without any love from their parents? Does it help to make them feel loved, or does rather that core hurt need to be tackled? In other words, can love from friends and relatives reduce the hurt, or does the issue need to be confronted directly?
Past issues are hard to tackle.  They become wired in the brain and can manifest into feelings of helplessness, depression, fear, anger etc.  Feeling unloved as a child can also lead to a self-fulfilling prophecy where you believe that being 'unloved' is part of your identity.  And because you have to be consistent with this identity, you may never really accept love or praise from someone who is genuine.

But no amount of love from someone else is going to resolve this issue!  The solution is to love yourself and to be a parent to yourself.  Get in touch with that inner child and tell it you love him/her.  Make praising yourself and loving yourself familiar.  

The most important relationship you should have is with yourself.  When you start to love yourself you become open to feeling loved.

So to solve this issue, I would do two things.  Firstly, I would get in touch with that feeling of feeling unloved and rejected, however painful it might be, and I would apply the Havening technique repeatedly until the pain has eased significantly.

Secondly, according to Marisa Peer, understand that feeling unloved or rejected as a child develops a belief, and therefore feeling of not being good enough.  So the next thing to do is to persevere with this:

repeat every day before you go to sleep, in the shower, brushing your teeth, before you wake up, put it on your phone alerts, phone screen saver, and even write it on your mirrors at home:

"I am enough.  I have always been enough, and I will always be enough."
"I like myself, I matter, I love myself."

Repeat these statements until you have deeply accepted them at a subconscious level.  

You see you can't hold a feeling of being unloved and rejected and a feeling of being enough at the same time!  But by communicating with yourself in a different way, it will change the way you feel about yourself.

It will take time, but it will work.  You can't change the memories of the past but we can change how we feel.  In your case, we can use the past as a catalyst for change and learn to become your own parent and friend and learn to make praising yourself a habit.

Peace