Product descriptions need to be comprehensive but that doesn’t mean they should be overly long. Few buyers will actually read it in its entirety. The solution is to split the description into two:

A summarized product description close to the product title
A comprehensive product description lower on the product page

The summarized description

It should be relatively short and easy to scan. The text should be organized in short bulleted points or a paragraph of four or five lines.

The summarized description should give a short overview of the product and list its key features. You can then add a “Read More” button or text link that opens the detailed product description.

The detailed product description

This one should be an in-depth look at the product covering all its features, benefits, manufacturing standards, and any certifications. Everything there is to know about the product should be available here.

The detailed description should be broken into sections and subsections for readability. Ideally, the benefits of every product attribute should be elaborated upon.

What not to do

Avoid overly technical language. The temptation will be there but you need to remember that the average customer isn’t that well-versed with the jargon of every specific industry. Use simple everyday language. If you have to include jargon, explain what it means. If a customer has to google the meaning of some of the terms you use, the results might just lead them to another site.
Avoid excessive use of marketing copy. According to Baymard, exaggerated language makes customers feel ‘oversold’. It damages your credibility as they will be less likely to believe any factual claims you make about the product; treating them as no more than marketing BS.