This will depend on the type of scheme you are applying for. For instance the maximum releases are usually available on the lifetime mortgage schemes such as the AVIVA lump sum max. For example a single male aged 65 can release a maximum amount of 30% of the property value on standard terms.
However, there are now three enhanced lifetime mortgage providers; Partnership, AVIVA & more2life. They will offer a higher release should answers from a health & lifestyle questionnaire be in your favour.
Therefore, if there are such issues with diabetes, heart attack, cancer, on medication or even a smoker, then a single male may qualify for an enhanced lifetime mortgage plan of upto 38.5%.
On a £200,000 property valuation this could mean an extra £17,000 tax free lump sum from the equity release company. So if you are looking for as much as possible the first port of call would be check medical history & see whether you qualify for the new enhanced equity release schemes.